Indian Patents. 257813:SEMICONDUCTOR MODULE

Title of Invention	SEMICONDUCTOR MODULE
Abstract	A semiconductor module has a housing, comprising a power semiconductor, a cooler bearing against the latter and serving for dissipating heat loss, and a spring element, which is supported between housing and cooler, is arranged on the side of the cooler remote from the power semiconductor and prestresses the cooler against the power semiconductor.

Full Text	Description Semiconductor module Power semiconductors are used nowadays in many areas of technology, e.g. industrial automation technology. In order that the corresponding power semiconductors or the circuits realized with them are made manipulable, they are generally integrated into a housing, e.g. composed of plastic. Arrangements of this type are referred to as semiconductor modules and are e.g. contactors, motor starters or the like. During operation, power semiconductors cause heat losses that can lead to their continuous heating and - if the heat that arises is not dissipated - to their destruction. The heat loss is generally dissipated preferably by means of an air cooling system or else by means of a water cooling system which is coupled to the power semiconductor. For heat dissipation, corresponding cooling systems have to be pressed as well as possible on to the power semiconductor or a part that is thermally coupled thereto. One location of this type is generally the carrier layer, e.g. a printed circuit board composed of ceramic (DCB - direct copper bonding). In the case of large quantities of heat to be dissipated, e.g. in converters, it is known for the power semiconductor and the cooler to be screwed to one another. By way of example, the generally quadrangular printed circuit board is screwed by means of a screw at each corner on a heat sink. In this case, as a result of the screws being tightened nonuniformly, a tilting can be brought about between cooler and power semiconductor, which can lead e.g. to fracture of the printed circuit board. Moreover, screws can be forgotten or tightened incorrectly or not at all. A final inspection of a correctly tightened screw during the manufacture of a semiconductor module is extremely costly. As a result of the settling of the screw head on its support, e.g. a plastic housing of a semiconductor module, a loss of prestress can occur over time and the contact pressure between cooler and printed circuit board can become impermissibly low. Moreover, screwing together cooler and power semiconductor necessitates drilling or thread cutting in cooler and printed circuit board. For lower-power semiconductors, e.g. in the case of microprocessors in PCs, it is also known to clamp a cooler on to the semiconductor by means of clamping springs. The corresponding clamping springs may be forgotten during mounting. For the clamping springs to engage, corresponding receptacles at which clamping clips or the like find a hold are generally necessary both on the cooler and on the semiconductor or semiconductor module. This requires an additional manufacturing step during their production. It is an object of the present invention to specify a semiconductor module with improved contact pressing of cooler and power semiconductor. The object is achieved by means of a semiconductor module with a housing, wherein a power semiconductor and a cooler are contained in the housing. The cooler bears against a cooling surface, which is thermally coupled to the power semiconductor, and serves for dissipating the heat loss thereof via the cooling surface. The cooling surface can, of course, also be the power semiconductor itself; it is rarely the case, however, since the power semiconductor - as explained above - is generally arranged on a carrying structure, e.g. a printed circuit board, which then has the cooling surface. According to the invention, in the semiconductor module a spring element is provided which is supported between housing and cooler, is arranged on that side of the cooler which is remote from the cooling surface, and prestresses the cooler against the cooling surface. In the semiconductor module according to the invention, therefore, the pressing of the cooler on to the cooling surface and thus the power part or the power semiconductor is achieved by means of a spring element which is supported alongside the cooler not on the power semiconductor but rather on the housing. In this case, the support of the spring element on the housing or on the cooler does not have to be over the whole area. The cooler is consequently pressed against the cooling surface by means of the housing of the semiconductor module. Consequently, the housing absorbs the prestress force between cooler and power semiconductor. Since the spring element between cooler and housing is generally supported by clamping, mechanical processing of the cooler is not necessary. Coolers are generally produced by the extrusion method and sawn to the corresponding length. That side of the cooler which is remote from the power semiconductor is thus generally planar. Since the spring element is generally supported on this planar side, no further processing is necessary there. The process for assembling the semiconductor module is simplified since no screwing operation or connection by means of spring clips is necessary. Screws or spring clips cannot be forgotten. During the assembly of the semiconductor module, the spring element is generally inserted into the housing and then pressed or clamped in between housing and cooler by assembly of the rest of the housing. This simple assembly results in a low risk of faults. The rapid assembly and the saving of individual parts such as screws or spring clips result in a saving of costs. The assembly of a housing with inserted spring element can generally be effected in translational fashion, thereby avoiding tilting between cooler and power semiconductor. The number of parts in the semiconductor module is reduced and the abovementioned loss of prestress of screws is avoided, particularly if the spring element bears against the housing or cooler over a large area. A simple quality control after assembly of the semiconductor module is possible since it is limited to the presence of the spring element, which, if it has been inserted then, that is to say is present, given a suitable configuration - e.g. in plate or disk form - cannot be inserted incorrectly. In this case, in a first embodiment of the invention, the spring element can be formed as a separate component. Suitable spring elements can then be stocked or replaced. The spring element can be a spring, in particular a spiral or leaf spring. Spring elements of this type are available cost- effectively as mass-produced products. The spring element can be an elastomer element. High press-on forces, e.g. comparable with a quadruple screw joint, can be achieved by corresponding selection and configuration of an elastomer part. Moreover, the elasticity of the elastomer makes it possible to compensate for large geometrical tolerances of the semiconductor module in conjunction with, nevertheless, a sufficient contact pressure. The elastomer element can be configured in plate form. As a result, it bears particularly well against cooler or housing. In a second alternative embodiment of the invention, the spring element can also be formed integrally with the housing. In this case, the spring element can e.g. be integrated in the housing by casting in if this is intrinsically a prefabricated separate part, such as e.g. a spring. However, the spring element can also be integrally formed directly on to the housing. The spring element can be an elastic partial structure of the housing. Thus, there may be present e.g. on the housing knobs, protrusions or shaped portions facing toward the inside of said housing, that is to say toward the cooler. The spring property of the spring element or the pressing of the cooler on to the cooling surface can then be provided by the elasticity of the housing material and the e.g. geometrical configuration of the corresponding integrally formed portions. The housing can have a latching device for the assembly of the semiconductor module under prestress of the spring element. The spring element is then e.g. inserted into the housing, the cooler is placed thereon and after, for the assembly of the semiconductor module, the power module or a corresponding second housing part is pressed onto the housing to an extent such that the corresponding prestress arises with compression of the spring element, the latching device latching in place only in the prestressed state. A corresponding latching can be achieved by manual assembly of the housing or pressing by means of a pressing device for higher contact pressures. The latching device can also engage into a partial structure carrying the power semiconductor or a part of the semiconductor module. A partial structure of this type is e.g. a preassembled power part comprising the semiconductor, the printed circuit board and a housing (upper) part. The latching device can also engage into the carrying structure, e.g. printed circuit board, or directly into the power semiconductor. The housing can also have a screw joint for assembly of the semiconductor module with prestress of the spring element. The screw joint then replaces or supplements the abovementioned latching in the same mode of operation. For a further description of the invention, reference is made to the exemplary embodiments in the drawings, in which in each case in a schematic basic diagram: Figure 1 shows a semiconductor module in cross section with an elastomer element as spring element, Figure 2 shows a semiconductor module in accordance with figure 1 in an alternative embodiment with press-on contour integrally formed onto the housing, Figure 3 shows a force-displacement diagram for the elastomer element in figure 1. Figure 1 shows a semiconductor module 2, comprising a power part 4, a cooler 6 and a cooler housing 8. A printed circuit board 10 together with power semiconductors 12 mounted thereon forms the actual power semiconductor circuit 14. The circuit 14 is connected to a housing upper part 16, in the example by means of a snap-action connection (not illustrated), in order together with this to form the power part 4. The cooler 6 comprises a cooler plate 18 and fins 20 integrally formed thereon. By its top side 22, the cooler plate 18 bears against the underside 24 of the printed circuit board 10, which represents the cooling surface for the power semiconductors 12. Thermally conductive paste (not illustrated) is introduced between the two. Heat loss from the semiconductor 12 is therefore conveyed via the printed circuit board 10 to the cooler plate 18 and to the cooling fins 20, through which cooling air flows. Between cooler 6 and cooler housing 8, an elastomer plate 34 is pressed on the base 32 of said housing. The cooler housing 8 essentially has the form of a parallelpiped open toward the top, that is to say toward the power part 4, that is to say is U-shaped in the cross section shown in figure 1. The cooler housing 8 has a plurality of cutouts 26 serving for engagement with latching lugs 28 which are in turn integrally formed on the housing upper part 16. Figure 1 shows the semiconductor module 2 in the finished assembled state. The following procedure is adopted during assembly: Firstly, in the direction of the arrow 30, an elastomer plate 32 is inserted into the as yet empty cooler housing 8 on to the inner side of the base 32. Afterward, the cooler 6 with the cooling fins 20 ahead is inserted into the cooler housing 8 likewise in the direction of the arrow 30. Afterward, the top side 22 is coated with thermally conductive paste and the preassembled housing upper part 16 with the underside 24 of the printed circuit board 10 ahead is placed onto the cooler 6. The elastomer plate 34 is as yet uncompressed and has the thickness d0. In the current situation, the latching lugs 28 cannot yet be brought into engagement with the cutouts 26 since the housing upper part 16 still projects from the cooler housing 8 counter to the direction of the arrow 30. By applying a force in the direction of the arrow 30 onto the housing upper part 16, the power part 4 together with the cooler 6 is then pressed in the direction of the base 32 and the elastomer plate 34 is compressed in the process, such that its thickness decreases from the initial value d0 to the compressed thickness di by a displacement s=do~di. The latching lugs 28 then latch into the cutouts 26. The elastomer part is now supported between base 32 and cooling fins 20 or the underside 36 thereof and generates respective press-on forces there which also act in each case between cooler 6, printed circuit board 10, housing upper part 16 or latching lugs 28 and cooler housing 8 or cutout 26. By this means, therefore, in particular the cooler plate 18 is prestressed against the printed circuit board 10 on the cooling surface. Figure 3 shows a curve 52 in a force-displacement diagram by way of example for the elastomer plate 34. The compression displacement s, that is to say the difference between do and d1 from figure 1, is plotted on the abscissa and the force F supplied back by the elastomer plate 34 is plotted on the ordinate. The geometrical dimensioning of the semiconductor module 2 is embodied in such a way that in the finished assembled state in accordance with figure 1, the elastomer plate is compressed by s0 with respect to the initial thickness d0. This results in a press-on force of F0 between the cooler plate 18 and the printed circuit board 10, which ensures sufficient thermal conduction. The entire component tolerances in the semiconductor module 2 are designed in such a way that in one extreme case, the elastomer plate 34 is still compressed by Smin proceeding from the thickness d0. The minimum press-on force therefore turns out to be Fmin, in figure 3. In the case of the opposite maximum tolerance situation, a compression of the elastomer plate 34 by smax results, which leads to a press-on force of Fmax. The elastomer plate 34 can therefore compensate for geometrical tolerances As within a wide range of Δs=smax_smin without in the process bringing about an impermissibly low or high contact pressure in the semiconductor module 2. Figure 2 shows an alternative embodiment of a semiconductor module 2 which is otherwise structurally identical to figure 1. Figure 2 shows a section along the line II-II from figure 1, figure 1 showing a section along the line I-I through figure 2. Figure 2 therefore also reveals the mounting structure 72 integrally formed on the cooler housing 8, said mounting structure serving for fixing the semiconductor module 2 e.g. in a switchgear cabinet. The elastomer plate 34 from figure 1 is replaced in figure 2 by protrusions 70 in the base 32 of the cooler housing 8, said protrusions being directed toward the interior of the cooler housing 8. In this case, the protrusions 70 are introduced into the cooler housing 8 by cutting free and deforming the material of the cooler housing 8, e.g. plastic, and are compressively elastic in the direction of the arrow 30. Therefore, the spring element according to the invention is in this case embodied integrally with the cooler housing 8. The protrusions 70 are in each case supported at a plurality of locations over the length of a cooling fin 20. Through corresponding geometrical configuration of the protrusions 70 or a material selection of the cooler housing 8, a force- displacement characteristic curve corresponding to that with regard to the curve 52 from figure 3 can be realized for said protrusions. Figure 2 also reveals that the cooler 6 is cut from an extruded profile extending in the direction of the arrow 74. The top side 22 and underside 36 are therefore planar in the direction of the arrow 74 as early as production. In figure 2, in contrast to figure 1, moreover, the latching comprising latching lugs 28 and cutouts 26 is replaced by a screw joint 76 (not explained in greater detail), which presses the housing upper part 16 down against a cooler housing 8 in the direction of the arrow 30 and thus compresses the protrusions 70 to the thickness d1. WE CLAIM: 1. A semiconductor module (2) with a housing (8, 16), comprising a power semiconductor (12), an integral cooler (6) bearing against a cooling surface (24), which is thermally coupled to the power semiconductor (12), and serving for dissipating heat loss, and a spring element (34, 70), which is supported between housing (8, 16) and cooler (6), is arranged on the side (36) of the cooler (6) remote from the cooling surface (24) and prestresses the cooler (6) against the cooling surface (24), wherein the cooler (6) comprises a cooler plate (18) and fins (20) integrally formed thereon. 2. The semiconductor module (2) as claimed in claim 1, comprising a spring element (34, 70) arranged between housing (8, 16) and cooler (6) and formed as a separate component. 3. The semiconductor module (2) as claimed in claim 1 or 2, wherein the spring element (34, 70) is a spring, in particular a spiral or leaf spring. 4. The semiconductor module (2) as claimed in claim 1 or 2, wherein the spring element (34, 70) is an elastomer element (34). 5. The semiconductor module (2) as claimed in claim 4, wherein the elastomer element (34) is in plate form. 6. The semiconductor module (2) as claimed in any of the preceding claims, comprising a spring element (34, 70) formed integrally with the housing (8,16). 7. The semiconductor module (2) as claimed in claim 6, wherein the spring element (34, 70) is an elastic partial structure (70) of the housing (8,16). 8. The semiconductor module (2) as claimed in claim 7, wherein the spring element (34, 70) is a protrusion (70) of the housing (8, 16) that is directed toward the cooler (6). 9. The semiconductor module (2) as claimed in any of the preceding claims, wherein the housing (8, 16) has a latching device (26, 28) for the assembly of the semiconductor module (2) under prestress of the spring element (34, 70). 10. The semiconductor module (2) as claimed in claim 9, wherein the latching device (26, 28) engages on a part (4) of the semiconductor module (2) that carries the power semiconductor (12). 11. The semiconductor module (2) as claimed in any of the preceding claims, wherein the housing (8,16) has a screw joint (76) for the assembly of the semiconductor module (2) under prestress of the spring element (34, 70). Abstract Semiconductor module A semiconductor module has a housing, comprising a power semiconductor, a cooler bearing against the latter and serving for dissipating heat loss, and a spring element, which is supported between housing and cooler, is arranged on the side of the cooler remote from the power semiconductor and prestresses the cooler against the power semiconductor.

Full Text

Description
Semiconductor module
Power semiconductors are used nowadays in many areas of
technology, e.g. industrial automation technology. In order
that the corresponding power semiconductors or the circuits
realized with them are made manipulable, they are generally
integrated into a housing, e.g. composed of plastic.
Arrangements of this type are referred to as semiconductor
modules and are e.g. contactors, motor starters or the like.
During operation, power semiconductors cause heat losses that
can lead to their continuous heating and - if the heat that
arises is not dissipated - to their destruction. The heat loss
is generally dissipated preferably by means of an air cooling
system or else by means of a water cooling system which is
coupled to the power semiconductor. For heat dissipation,
corresponding cooling systems have to be pressed as well as
possible on to the power semiconductor or a part that is
thermally coupled thereto. One location of this type is
generally the carrier layer, e.g. a printed circuit board
composed of ceramic (DCB - direct copper bonding).
In the case of large quantities of heat to be dissipated, e.g.
in converters, it is known for the power semiconductor and the
cooler to be screwed to one another. By way of example, the
generally quadrangular printed circuit board is screwed by
means of a screw at each corner on a heat sink. In this case,
as a result of the screws being tightened nonuniformly, a
tilting can be brought about between cooler and power
semiconductor, which can lead e.g. to fracture of the printed
circuit board. Moreover, screws can be forgotten or tightened
incorrectly or not at all. A final inspection of a correctly
tightened screw during the manufacture of a semiconductor
module is extremely costly. As a result of the settling of the
screw head on its support, e.g. a plastic housing of a
semiconductor module, a loss of prestress can occur over time

and the contact pressure between cooler and printed circuit
board can become impermissibly low. Moreover, screwing together
cooler and power semiconductor necessitates drilling or thread
cutting in cooler and printed circuit board.
For lower-power semiconductors, e.g. in the case of
microprocessors in PCs, it is also known to clamp a cooler on
to the semiconductor by means of clamping springs. The
corresponding clamping springs may be forgotten during
mounting. For the clamping springs to engage, corresponding
receptacles at which clamping clips or the like find a hold are
generally necessary both on the cooler and on the semiconductor
or semiconductor module. This requires an additional
manufacturing step during their production.
It is an object of the present invention to specify a
semiconductor module with improved contact pressing of cooler
and power semiconductor.
The object is achieved by means of a semiconductor module with
a housing, wherein a power semiconductor and a cooler are
contained in the housing. The cooler bears against a cooling
surface, which is thermally coupled to the power semiconductor,
and serves for dissipating the heat loss thereof via the
cooling surface. The cooling surface can, of course, also be
the power semiconductor itself; it is rarely the case, however,
since the power semiconductor - as explained above - is
generally arranged on a carrying structure, e.g. a printed
circuit board, which then has the cooling surface.
According to the invention, in the semiconductor module a
spring element is provided which is supported between housing
and cooler, is arranged on that side of the cooler which is
remote from the cooling surface, and prestresses the cooler
against the cooling surface.

In the semiconductor module according to the invention,
therefore, the pressing of the cooler on to the cooling surface
and thus the power part or the power semiconductor is achieved
by means of a spring element which is supported alongside the
cooler not on the power semiconductor but rather on the
housing. In this case, the support of the spring element on the
housing or on the cooler does not have to be over the whole
area. The cooler is consequently pressed against the cooling
surface by means of the housing of the semiconductor module.
Consequently, the housing absorbs the prestress force between
cooler and power semiconductor. Since the spring element
between cooler and housing is generally supported by clamping,
mechanical processing of the cooler is not necessary. Coolers
are generally produced by the extrusion method and sawn to the
corresponding length. That side of the cooler which is remote
from the power semiconductor is thus generally planar. Since
the spring element is generally supported on this planar side,
no further processing is necessary there.
The process for assembling the semiconductor module is
simplified since no screwing operation or connection by means
of spring clips is necessary. Screws or spring clips cannot be
forgotten.
During the assembly of the semiconductor module, the spring
element is generally inserted into the housing and then pressed
or clamped in between housing and cooler by assembly of the
rest of the housing. This simple assembly results in a low risk
of faults. The rapid assembly and the saving of individual
parts such as screws or spring clips result in a saving of
costs. The assembly of a housing with inserted spring element
can generally be effected in translational fashion, thereby
avoiding tilting between cooler and power semiconductor.
The number of parts in the semiconductor module is reduced and
the abovementioned loss of prestress of screws is avoided,
particularly if the spring element bears against the housing or

cooler over a large area. A simple quality control after
assembly of the semiconductor module is possible since it is
limited to the presence of the spring element, which, if it has
been inserted then, that is to say is present, given a suitable
configuration - e.g. in plate or disk form - cannot be inserted
incorrectly.
In this case, in a first embodiment of the invention, the
spring element can be formed as a separate component. Suitable
spring elements can then be stocked or replaced.
The spring element can be a spring, in particular a spiral or
leaf spring. Spring elements of this type are available cost-
effectively as mass-produced products.
The spring element can be an elastomer element. High press-on
forces, e.g. comparable with a quadruple screw joint, can be
achieved by corresponding selection and configuration of an
elastomer part. Moreover, the elasticity of the elastomer makes
it possible to compensate for large geometrical tolerances of
the semiconductor module in conjunction with, nevertheless, a
sufficient contact pressure.
The elastomer element can be configured in plate form. As a
result, it bears particularly well against cooler or housing.
In a second alternative embodiment of the invention, the spring
element can also be formed integrally with the housing. In this
case, the spring element can e.g. be integrated in the housing
by casting in if this is intrinsically a prefabricated separate
part, such as e.g. a spring. However, the spring element can
also be integrally formed directly on to the housing.
The spring element can be an elastic partial structure of the
housing. Thus, there may be present e.g. on the housing knobs,
protrusions or shaped portions facing toward the inside of said
housing, that is to say toward the cooler. The spring property

of the spring element or the pressing of the cooler on to the
cooling surface can then be provided by the elasticity of the
housing material and the e.g. geometrical configuration of the
corresponding integrally formed portions.
The housing can have a latching device for the assembly of the
semiconductor module under prestress of the spring element. The
spring element is then e.g. inserted into the housing, the
cooler is placed thereon and after, for the assembly of the
semiconductor module, the power module or a corresponding
second housing part is pressed onto the housing to an extent
such that the corresponding prestress arises with compression
of the spring element, the latching device latching in place
only in the prestressed state.
A corresponding latching can be achieved by manual assembly of
the housing or pressing by means of a pressing device for
higher contact pressures.
The latching device can also engage into a partial structure
carrying the power semiconductor or a part of the semiconductor
module. A partial structure of this type is e.g. a preassembled
power part comprising the semiconductor, the printed circuit
board and a housing (upper) part. The latching device can also
engage into the carrying structure, e.g. printed circuit board,
or directly into the power semiconductor.
The housing can also have a screw joint for assembly of the
semiconductor module with prestress of the spring element. The
screw joint then replaces or supplements the abovementioned
latching in the same mode of operation.
For a further description of the invention, reference is made
to the exemplary embodiments in the drawings, in which in each
case in a schematic basic diagram:

Figure 1 shows a semiconductor module in cross section with an
elastomer element as spring element,
Figure 2 shows a semiconductor module in accordance with
figure 1 in an alternative embodiment with press-on
contour integrally formed onto the housing,
Figure 3 shows a force-displacement diagram for the elastomer
element in figure 1.
Figure 1 shows a semiconductor module 2, comprising a power
part 4, a cooler 6 and a cooler housing 8. A printed circuit
board 10 together with power semiconductors 12 mounted thereon
forms the actual power semiconductor circuit 14. The circuit 14
is connected to a housing upper part 16, in the example by
means of a snap-action connection (not illustrated), in order
together with this to form the power part 4.
The cooler 6 comprises a cooler plate 18 and fins 20 integrally
formed thereon. By its top side 22, the cooler plate 18 bears
against the underside 24 of the printed circuit board 10, which
represents the cooling surface for the power semiconductors 12.
Thermally conductive paste (not illustrated) is introduced
between the two. Heat loss from the semiconductor 12 is
therefore conveyed via the printed circuit board 10 to the
cooler plate 18 and to the cooling fins 20, through which
cooling air flows. Between cooler 6 and cooler housing 8, an
elastomer plate 34 is pressed on the base 32 of said housing.
The cooler housing 8 essentially has the form of a
parallelpiped open toward the top, that is to say toward the
power part 4, that is to say is U-shaped in the cross section
shown in figure 1. The cooler housing 8 has a plurality of
cutouts 26 serving for engagement with latching lugs 28 which
are in turn integrally formed on the housing upper part 16.
Figure 1 shows the semiconductor module 2 in the finished
assembled state. The following procedure is adopted during
assembly: Firstly, in the direction of the arrow 30, an

elastomer plate 32 is inserted into the as yet empty cooler
housing 8 on to the inner side of the base 32. Afterward, the
cooler 6 with the cooling fins 20 ahead is inserted into the
cooler housing 8 likewise in the direction of the arrow 30.
Afterward, the top side 22 is coated with thermally conductive
paste and the preassembled housing upper part 16 with the
underside 24 of the printed circuit board 10 ahead is placed
onto the cooler 6. The elastomer plate 34 is as yet
uncompressed and has the thickness d0. In the current
situation, the latching lugs 28 cannot yet be brought into
engagement with the cutouts 26 since the housing upper part 16
still projects from the cooler housing 8 counter to the
direction of the arrow 30. By applying a force in the direction
of the arrow 30 onto the housing upper part 16, the power part
4 together with the cooler 6 is then pressed in the direction
of the base 32 and the elastomer plate 34 is compressed in the
process, such that its thickness decreases from the initial
value d0 to the compressed thickness di by a displacement
s=do~di. The latching lugs 28 then latch into the cutouts 26.
The elastomer part is now supported between base 32 and cooling
fins 20 or the underside 36 thereof and generates respective
press-on forces there which also act in each case between
cooler 6, printed circuit board 10, housing upper part 16 or
latching lugs 28 and cooler housing 8 or cutout 26. By this
means, therefore, in particular the cooler plate 18 is
prestressed against the printed circuit board 10 on the cooling
surface.
Figure 3 shows a curve 52 in a force-displacement diagram by
way of example for the elastomer plate 34. The compression
displacement s, that is to say the difference between do and d1
from figure 1, is plotted on the abscissa and the force F
supplied back by the elastomer plate 34 is plotted on the
ordinate.

The geometrical dimensioning of the semiconductor module 2 is
embodied in such a way that in the finished assembled state in
accordance with figure 1, the elastomer plate is compressed by
s0 with respect to the initial thickness d0. This results in a
press-on force of F0 between the cooler plate 18 and the
printed circuit board 10, which ensures sufficient thermal
conduction. The entire component tolerances in the
semiconductor module 2 are designed in such a way that in one
extreme case, the elastomer plate 34 is still compressed by Smin
proceeding from the thickness d0. The minimum press-on force
therefore turns out to be Fmin, in figure 3. In the case of the
opposite maximum tolerance situation, a compression of the
elastomer plate 34 by smax results, which leads to a press-on
force of Fmax. The elastomer plate 34 can therefore compensate
for geometrical tolerances As within a wide range of
Δs=smax_smin without in the process bringing about an
impermissibly low or high contact pressure in the semiconductor
module 2.
Figure 2 shows an alternative embodiment of a semiconductor
module 2 which is otherwise structurally identical to figure 1.
Figure 2 shows a section along the line II-II from figure 1,
figure 1 showing a section along the line I-I through figure 2.
Figure 2 therefore also reveals the mounting structure 72
integrally formed on the cooler housing 8, said mounting
structure serving for fixing the semiconductor module 2 e.g. in
a switchgear cabinet. The elastomer plate 34 from figure 1 is
replaced in figure 2 by protrusions 70 in the base 32 of the
cooler housing 8, said protrusions being directed toward the
interior of the cooler housing 8. In this case, the protrusions
70 are introduced into the cooler housing 8 by cutting free and
deforming the material of the cooler housing 8, e.g. plastic,
and are compressively elastic in the direction of the arrow 30.
Therefore, the spring element according to the invention is in
this case embodied integrally with the cooler housing 8.

The protrusions 70 are in each case supported at a plurality of
locations over the length of a cooling fin 20. Through
corresponding geometrical configuration of the protrusions 70
or a material selection of the cooler housing 8, a force-
displacement characteristic curve corresponding to that with
regard to the curve 52 from figure 3 can be realized for said
protrusions. Figure 2 also reveals that the cooler 6 is cut
from an extruded profile extending in the direction of the
arrow 74. The top side 22 and underside 36 are therefore planar
in the direction of the arrow 74 as early as production.
In figure 2, in contrast to figure 1, moreover, the latching
comprising latching lugs 28 and cutouts 26 is replaced by a
screw joint 76 (not explained in greater detail), which presses
the housing upper part 16 down against a cooler housing 8 in
the direction of the arrow 30 and thus compresses the
protrusions 70 to the thickness d1.

WE CLAIM:
1. A semiconductor module (2) with a housing (8, 16), comprising a power
semiconductor (12), an integral cooler (6) bearing against a cooling
surface (24), which is thermally coupled to the power semiconductor (12),
and serving for dissipating heat loss, and a spring element (34, 70), which
is supported between housing (8, 16) and cooler (6), is arranged on the
side (36) of the cooler (6) remote from the cooling surface (24) and
prestresses the cooler (6) against the cooling surface (24), wherein the
cooler (6) comprises a cooler plate (18) and fins (20) integrally formed
thereon.
2. The semiconductor module (2) as claimed in claim 1, comprising a spring
element (34, 70) arranged between housing (8, 16) and cooler (6) and
formed as a separate component.
3. The semiconductor module (2) as claimed in claim 1 or 2, wherein the
spring element (34, 70) is a spring, in particular a spiral or leaf spring.
4. The semiconductor module (2) as claimed in claim 1 or 2, wherein the
spring element (34, 70) is an elastomer element (34).
5. The semiconductor module (2) as claimed in claim 4, wherein the
elastomer element (34) is in plate form.
6. The semiconductor module (2) as claimed in any of the preceding claims,
comprising a spring element (34, 70) formed integrally with the housing
(8,16).

7. The semiconductor module (2) as claimed in claim 6, wherein the spring
element (34, 70) is an elastic partial structure (70) of the housing (8,16).
8. The semiconductor module (2) as claimed in claim 7, wherein the spring
element (34, 70) is a protrusion (70) of the housing (8, 16) that is
directed toward the cooler (6).
9. The semiconductor module (2) as claimed in any of the preceding claims,
wherein the housing (8, 16) has a latching device (26, 28) for the
assembly of the semiconductor module (2) under prestress of the spring
element (34, 70).
10. The semiconductor module (2) as claimed in claim 9, wherein the latching
device (26, 28) engages on a part (4) of the semiconductor module (2)
that carries the power semiconductor (12).
11. The semiconductor module (2) as claimed in any of the preceding claims,
wherein the housing (8,16) has a screw joint (76) for the assembly of the
semiconductor module (2) under prestress of the spring element (34, 70).

Abstract

Semiconductor module
A semiconductor module has a housing, comprising a power
semiconductor, a cooler bearing against the latter and serving
for dissipating heat loss, and a spring element, which is
supported between housing and cooler, is arranged on the side
of the cooler remote from the power semiconductor and
prestresses the cooler against the power semiconductor.

Documents:

00609-kol-2008-abstract.pdf

00609-kol-2008-claims.pdf

00609-kol-2008-correspondence others.pdf

00609-kol-2008-description complete.pdf

00609-kol-2008-drawings.pdf

00609-kol-2008-form 1.pdf

00609-kol-2008-form 2.pdf

00609-kol-2008-form 3.pdf

00609-kol-2008-form 5.pdf

00609-kol-2008-gpa.pdf

00609-kol-2008-priority document.pdf

00609-kol-2008-translated copy of priority document.pdf

609-KOL-2008-(26-12-2012)-ABSTRACT.pdf

609-KOL-2008-(26-12-2012)-CLAIMS.pdf

609-KOL-2008-(26-12-2012)-CORRESPONDENCE.pdf

609-KOL-2008-(26-12-2012)-DESCRIPTION (COMPLETE).pdf

609-KOL-2008-(26-12-2012)-FORM 1.pdf

609-KOL-2008-(26-12-2012)-FORM 2.pdf

609-KOL-2008-(26-12-2012)-FORM 3.pdf

609-KOL-2008-(26-12-2012)-OTHERS.pdf

609-KOL-2008-(26-12-2012)-PETITION UNDER RULE 137-1.pdf

609-KOL-2008-(26-12-2012)-PETITION UNDER RULE 137.pdf

609-KOL-2008-CANCELLED PAGES.pdf

609-KOL-2008-CORRESPONDENCE.pdf

609-KOL-2008-EXAMINATION REPORT.pdf

609-KOL-2008-FORM 18-1.1.pdf

609-kol-2008-form 18.pdf

609-KOL-2008-GPA.pdf

609-KOL-2008-GRANTED-ABSTRACT.pdf

609-KOL-2008-GRANTED-CLAIMS.pdf

609-KOL-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

609-KOL-2008-GRANTED-DRAWINGS.pdf

609-KOL-2008-GRANTED-FORM 1.pdf

609-KOL-2008-GRANTED-FORM 2.pdf

609-KOL-2008-GRANTED-FORM 3.pdf

609-KOL-2008-GRANTED-FORM 5.pdf

609-KOL-2008-GRANTED-SPECIFICATION-COMPLETE.pdf

609-KOL-2008-PETITION UNDER RULE 137.pdf

609-KOL-2008-PRIORITY DOCUMENT.pdf

609-KOL-2008-REPLY TO EXAMINATION REPORT.pdf

609-KOL-2008-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

abstract-00609-kol-2008.jpg

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Patent Number

257813

Indian Patent Application Number

609/KOL/2008

PG Journal Number

45/2013

Publication Date

08-Nov-2013

Grant Date

06-Nov-2013

Date of Filing

26-Mar-2008

Name of Patentee

SIEMENS AKTIENGESELLSCHAFT

Applicant Address

WITTELSBACHERPLATZ 2, 80333 MUNCHEN

Inventors:

#	Inventor's Name	Inventor's Address
1	MARKUS MEIER	BLUMENTHALSTR. 27 92286 RIEDEN

PCT International Classification Number

H01L29/739; H01L21/331

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	EP07007557	2007-04-12	EPO