Title of Invention	" A PROCESS FOR PURIFICATION OF COMMERCIAL GRADE HYDROCHLORIC ACID FOR SEMICONDUCTORS'
Abstract	This invention relates to a process for purification of commercial grade hydrochloric acid for semiconductors comprising steps of passing sulphuric acid in Hydrochloric acid contained in a container to generate HCI gas, passing said HCI gas through a liquid containing saturated hydrochloric acid for removal of impurities, passing the pure hydrochloric acid gas through deionized water to obtain hydrochloric acids for semiconductors.

Title of Invention

" A PROCESS FOR PURIFICATION OF COMMERCIAL GRADE HYDROCHLORIC ACID FOR SEMICONDUCTORS'

Abstract

This invention relates to a process for purification of commercial grade hydrochloric acid for semiconductors comprising steps of passing sulphuric acid in Hydrochloric acid contained in a container to generate HCI gas, passing said HCI gas through a liquid containing saturated hydrochloric acid for removal of impurities, passing the pure hydrochloric acid gas through deionized water to obtain hydrochloric acids for semiconductors.

Full Text	FILED OF INVENTION This invention relates to a process for the purification of hydrochloric acid for semiconductors. BACKGROUND OF INVENTION Materials used in electronic industry covers a wide range of materials such as metal, alloys, semiconductors, photoresists, specialty polymers, ceramics, glasses, thick film materials and PCB laminators. In the manufacturing process of the components, cleaning is an important step to avoid the dust and impurity contamination. The contamination source is from atmosphere, from existing process or from any other foreign matter. The soldering flux is used in electronic assembles and residue after soldering needs to clean with the high purity acids. The soldering flux residue contains inorganic impurities and it needs to be clean by specific grade acids, namely semiconductor grade acids. Acid solutions are also capable of removing metal oxides, metal hydroxides and resin smear. Ultra pure i.e. semiconductor grade hydrochloric acid is one of the acids used by electronic industries. Removal of critical impurities from hydrochloric acid is difficult as traces of metallic impurities affect the performance of semiconductor devices. Hydrochloric acid is extensively used for degreasing, cleaning etc. during semiconductor processing in the electronics industry. The purity of HC1 should be very high. The impurity level of trace metal should be less than lppm. The particulate content should meet the specifications of class 0-2 of the semi standard classification i.e. maximum number of particles above 5 micron should be less than 35 per ml. Though the technology for HC1 production is available in the country, the purity is not of required level HC1 production is a well established technology. However, negligible work on such high purity chemicals has been carried out. OBJECTS OF THE INVENTION An object of this invention is to propose an improved process and apparatus for producing hydrochloric acid of high purity for semiconductors. Another object of this invention is to propose an improved process and apparatus for producing hydrochloric acid for semiconductors from cheap raw materials. BRIEF DESCRIPTION OF INVENTION According to this invention there is provided a process for purification of commercial grade hydrochloric acid for semiconductors comprising steps of:- i) passing sulphuric acid in Hydrochloric acid contained in a container to generate HCI gas, ii) passing said HCI gas through a liquid containing saturated hydrochloric acid for removal of impurities, iii) passing the pure hydrochloric acid gas through deionized water to obtain hydrochloric acids for semiconductors. In accordance with this invention HCI is filled in a first container, and H2SO4 is filled in a second container. The H2SO4 container is placed above the HCI container. HSO container has arrangement to control the flow of H2SO4 which is added to commercial HCI. Commercial grade HCI is taken in vessel having outlet for gas and inlet for H2SO4 addition. Commercial grade H2SO4 is taken in H2SO4 container. The addition of H2SO4 is effected and as H2SO4 has high affinity towards water, it absorbs water from HCI and the concentration of HCI increase as the reaction proceeds further. The reaction of water and H2SO4 is exothermic which o increases the temperature around 70-80 C of the solution. The increase in temperature as well as concentration of the mixture generates HCl gas. This gas is passed through a liquid trap which contains saturated HCl where the impurities get trapped and HCl gas was taken for further processing. The following reaction takes place in the gas generation system. (Formula Removed) DISSOLUTION SYSTEM The solution system comprises an arrangement for the pure HCl gas to be bubbled in deionized water. The HCl gas has high solubility in water hence no gas is escaping from this dissolution system. The HCl obtained in this vessel after acquiring required concentration is replaced with fresh deionized water. The dissolution of HCl in water is exothermic reaction hence cooling is necessary during this process. The following reaction takes place in dissolution system. (Formula Removed) Based on the yield of final product it is estimated that 90% of the HC1 gas from commercial grade HC1 is recovered by this process. The final product obtained is filtered. The process for the preparation of hydrochloric acid for semiconductors is described and illustrated in the following examples. Example 1 The 250ml commercial grade HC1 (30%) was taken in HC1 container and 250ml commercial grade H SO (92-94%) was taken H2SO4 container. 110ml deionized water was taken in gas dissolution container and 50ml of commercial HC1 was taken in the trap whidh connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in 30 mins. The volume of final product obtained was 150ml and it was analyzed for its assay i.e. HC1 content (37.5%). The detail tests like Phosphate, Sulphate, Sulphite and Color were carried out. Trace metal impurities were determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 75%. EXAMPLE 2 The 800ml commercial grade HCl (30%) was taken in HCl container and 1000ml commercial grade H2SO4 (92-94%) was taken in H2SO4 container 350ml Deionized water was taken in gas dissolution container and 150ml of commercial HCl was taken in the trap which connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in one hour. The volume of final product obtained was 510ml and it was analyzed for its assay i.e. HCl content (36.5%). The detail tests like Phosphate, Sulphite and Color were carried out. Trace metal impurities were determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 79%. EXAMPLE 3 The 1500ml commercial grade HCl (30%) was taken in HCl container and 1500ml commercial grade H SO (92-94%) was taken in H2SO4 container. 700ml Deionized water was taken in gas dissolution container and 300ml of commercial HCl was taken in the trap which connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in 1 hours. The volume of final product obtained was 1020ml and it was analyzed for its assay i.e. HCl content (38.9%). The detail tests like Phosphate, Sulphate, Sulphite and Color were carried out. Trace metal impurities were determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 88%. WE CLAIM: 1. A process for purification of commercial grade hydrochloric acid for semiconductors comprising steps of:- i) passing sulphuric acid in Hydrochloric acid contained in a container to generate HCI gas, ii) passing said HCI gas through a liquid containing saturated hydrochloric acid for removal of impurities, iii) passing the pure hydrochloric acid gas through deionized water to obtain hydrochloric acids for semiconductors. 2. A process as claimed in claim 1 wherein said pure HCI gas is passed through the deionized water till the pure HCI of the required concentration is obtained. 3. A process for purification of commercial grade hydrochloric acid for semiconductors substantially as herein described.

Full Text

FILED OF INVENTION
This invention relates to a process for the purification of hydrochloric acid for semiconductors.
BACKGROUND OF INVENTION
Materials used in electronic industry covers a wide range of materials such as metal, alloys, semiconductors, photoresists, specialty polymers, ceramics, glasses, thick film materials and PCB laminators. In the manufacturing process of the components, cleaning is an important step to avoid the dust and impurity contamination. The contamination source is from atmosphere, from existing process or from any other foreign matter. The soldering flux is used in electronic assembles and residue after soldering needs to clean with the high purity acids. The soldering flux residue contains inorganic impurities and it needs to be clean by specific grade acids, namely semiconductor grade acids. Acid solutions are also capable of removing metal oxides, metal hydroxides and resin smear.
Ultra pure i.e. semiconductor grade hydrochloric acid is one of the acids used by electronic industries. Removal of critical impurities from

hydrochloric acid is difficult as traces of metallic impurities affect the performance of semiconductor devices. Hydrochloric acid is extensively used for degreasing, cleaning etc. during semiconductor processing in the electronics industry. The purity of HC1 should be very high. The impurity level of trace metal should be less than lppm. The particulate content should meet the specifications of class 0-2 of the semi standard classification i.e. maximum number of particles above 5 micron should be less than 35 per ml.
Though the technology for HC1 production is available in the country, the purity is not of required level HC1 production is a well established technology. However, negligible work on such high purity chemicals has been carried out. OBJECTS OF THE INVENTION
An object of this invention is to propose an improved process and apparatus for producing hydrochloric acid of high purity for semiconductors.
Another object of this invention is to propose an improved process and apparatus for producing hydrochloric acid for semiconductors from cheap raw materials.

BRIEF DESCRIPTION OF INVENTION
According to this invention there is provided a process for purification of commercial grade hydrochloric acid for semiconductors comprising steps of:-
i) passing sulphuric acid in Hydrochloric acid contained in a
container to generate HCI gas, ii) passing said HCI gas through a liquid containing
saturated hydrochloric acid for removal of impurities, iii) passing the pure hydrochloric acid gas through deionized
water to obtain hydrochloric acids for semiconductors.
In accordance with this invention HCI is filled in a first container, and H2SO4 is filled in a second container. The H2SO4 container is placed above the HCI container. HSO container has arrangement to control the flow of H2SO4 which is added to commercial HCI. Commercial grade HCI is taken in vessel having outlet for gas and inlet for H2SO4 addition. Commercial grade H2SO4 is taken in H2SO4 container. The addition of H2SO4 is effected and as H2SO4 has high affinity towards water, it absorbs water from HCI and the concentration of HCI increase as the reaction proceeds further. The reaction of water and H2SO4 is exothermic which

o increases the temperature around 70-80 C of the
solution. The increase in temperature as well as
concentration of the mixture generates HCl gas. This
gas is passed through a liquid trap which contains
saturated HCl where the impurities get trapped and HCl
gas was taken for further processing. The following
reaction takes place in the gas generation system.
(Formula Removed)
DISSOLUTION SYSTEM
The solution system comprises an arrangement for the pure HCl gas to be bubbled in deionized water. The HCl gas has high solubility in water hence no gas is escaping from this dissolution system. The HCl obtained in this vessel after acquiring required concentration is replaced with fresh deionized water. The dissolution of HCl in water is exothermic reaction hence cooling is necessary during this process. The following reaction takes place in dissolution system.

(Formula Removed)
Based on the yield of final product it is estimated that
90% of the HC1 gas from commercial grade HC1 is
recovered by this process. The final product obtained
is filtered.
The process for the preparation of hydrochloric acid for semiconductors is described and illustrated in the following examples.
Example 1
The 250ml commercial grade HC1 (30%) was taken in HC1 container and 250ml commercial grade H SO (92-94%) was taken H2SO4 container. 110ml deionized water was taken in gas dissolution container and 50ml of commercial HC1 was taken in the trap whidh connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in 30 mins. The volume of final product obtained was 150ml and it was analyzed for its assay i.e. HC1 content (37.5%). The detail tests like Phosphate, Sulphate, Sulphite and Color were carried out. Trace metal impurities were

determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 75%.
EXAMPLE 2
The 800ml commercial grade HCl (30%) was taken in HCl container and 1000ml commercial grade H2SO4
(92-94%) was taken in H2SO4 container 350ml Deionized water was taken in gas dissolution container and 150ml of commercial HCl was taken in the trap which connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in one hour. The volume of final product obtained was 510ml and it was analyzed for its assay i.e. HCl content
(36.5%). The detail tests like Phosphate, Sulphite and Color were carried out. Trace metal impurities were determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 79%.
EXAMPLE 3
The 1500ml commercial grade HCl (30%) was
taken in HCl container and 1500ml commercial grade H SO
(92-94%) was taken in H2SO4 container. 700ml Deionized
water was taken in gas dissolution container and 300ml

of commercial HCl was taken in the trap which connected in between the gas generation unit and dissolution unit. The reaction has been started and completed in 1 hours. The volume of final product obtained was 1020ml and it was analyzed for its assay i.e. HCl content (38.9%). The detail tests like Phosphate, Sulphate, Sulphite and Color were carried out. Trace metal impurities were determined by using ICP-OES. The total yield on the basis of HCl concentration was observed 88%.

WE CLAIM:
1. A process for purification of commercial grade
hydrochloric acid for semiconductors comprising steps
of:-
i) passing sulphuric acid in Hydrochloric acid contained in a
container to generate HCI gas, ii) passing said HCI gas through a liquid containing
saturated hydrochloric acid for removal of impurities, iii) passing the pure hydrochloric acid gas through deionized
water to obtain hydrochloric acids for semiconductors.
2. A process as claimed in claim 1 wherein said pure HCI gas is passed through the deionized water till the pure HCI of the required concentration is obtained.
3. A process for purification of commercial grade hydrochloric acid for semiconductors substantially as herein described.

Documents:

861-del-1999-abstract.pdf

861-del-1999-claims.pdf

861-del-1999-complete specification (granted).pdf

861-del-1999-correspondence-others.pdf

861-del-1999-correspondence-po.pdf

861-del-1999-description (complete).pdf

861-del-1999-description (provisional).pdf

861-del-1999-form-1.pdf

861-del-1999-form-19.pdf

861-del-1999-form-2.pdf

861-del-1999-form-26.pdf

861-del-1999-form-5.pdf

861-del-1999-petition-138.pdf

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Patent Number

242916

Indian Patent Application Number

861/DEL/1999

PG Journal Number

39/2010

Publication Date

24-Sep-2010

Grant Date

18-Sep-2010

Date of Filing

10-Jun-1999

Name of Patentee

SECRETARY,DEPARTMENT OF ELECTRONICS, GOVERMENT OF INDIA,

Applicant Address

ELECTRONICS NIKETAN,(GROUND FLOOR),6, C.G.O. COMPLEX, LODHI ROAD,NEW DELHI-110 003, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	S.K.APTE	CENTRE FOR MATERIALS FOR ELECTRONICS TECHNOLOGY, DEPARTMENT OF ELECTRONICS, GOVERNMENT OF INDIA,PANCHWATI OFF PASHAN ROAD, PUNE-411 008, MAHARASHTRA, INDIA.
2	U. RAMBABU	CENTRE FOR MATERIALS FOR ELECTRONICS TECHNOLOGY, DEPARTMENT OF ELECTRONICS, GOVERNMENT OF INDIA,PANCHWATI OFF PASHAN ROAD, PUNE-411 008, MAHARASHTRA, INDIA.
3	R.S. SONAWANE	CENTRE FOR MATERIALS FOR ELECTRONICS TECHNOLOGY, DEPARTMENT OF ELECTRONICS, GOVERNMENT OF INDIA,PANCHWATI OFF PASHAN ROAD, PUNE-411 008, MAHARASHTRA, INDIA.
4	B.B.KALE	CENTRE FOR MATERIALS FOR ELECTRONICS TECHNOLOGY, DEPARTMENT OF ELECTRONICS, GOVERNMENT OF INDIA,PANCHWATI OFF PASHAN ROAD, PUNE-411 008, MAHARASHTRA, INDIA.

PCT International Classification Number

B08B 03/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA