Manufacture of high precision electronic components with ultra-high purity liquids

Abstract

Semiconductor wafers and other electronic parts which similarly require ultra-high purity manufacturing environments are treated with ultra-high purity liquid cleaning and etching agents prepared at the site of use from gaseous raw materials which have been purified to a level compatible with semiconductor manufacturing standards, combined when appropriate with ultra-pure water.

What is claimed is: 
     
       1. A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of a liquid treatment agent to said workpiece;   (b) means for conveying said workpiece to said workstations in succession along said production line; and   (c) a subunit adjoining said production line at said selected workstation to supply said liquid treatment agent in ultra-high purity form, said subunit supplied by raw materials including a gaseous raw material selected from the group consisting of ammonia, hydrogen fluoride, hydrogen chloride, hydrogen bromide, phosphine, arsine, diborane and sulfur dioxide, and said subunit comprising: (i) means for purifying said gaseous raw material to a purity compatible with semiconductor manufacturing standards . .defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes other than said raw material itself, a particulate content of less than about 150/cm 3  and a particle size of less than 0.2 micron, a microorganism content of less than about 10/cm 3 , and total organic carbon of less than 100 ppb.!.;   (ii) means for combining said gaseous raw material so purified with further raw material of a purity compatible with said semiconductor manufacturing standards, under conditions such that said gaseous raw material and said further raw material are converted to said ultra-high purity liquid treatment agent at a rate approximately equal to that at which said liquid treatment agent will be applied to a workpiece; and   (iii) means for applying said ultra-high purity liquid treatment agent thus formed directly to a workpiece at said workstation;   said production line, said conveying means and said subunit all being contained in an environment maintained free of contamination by said semiconductor manufacturing standards.     
     
     
       2. A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of a liquid treatment agent to said workpiece;   (b) means for conveying said workpiece to said workstations in succession along said production line; and   (c) a subunit adjoining said production line at said selected workstation to supply said liquid treatment agent in ultra-high purity form, said subunit supplied by raw materials including a gaseous raw material and comprising: (i) means for purifying said gaseous raw material to a purity compatible with semiconductor manufacturing standards . .defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes other than said raw material itself, a particulate content of less than about 150/cm 3  and a particle size of less than 0.2 micron, a microorganism content of less than about 10/cm 3 , and total organic carbon of less than 100 ppb,.!..Iadd.; .Iaddend.said means for purifying said gaseous raw material including a filtration membrane removing particles greater than 0.005 micron;   (ii) means for combining said gaseous raw material so purified with further raw material of a purity compatible with said semiconductor manufacturing standards, under conditions such that said gaseous raw material and said further raw material are converted to said ultra-high purity liquid treatment agent at a rate approximately equal to that at which said liquid treatment agent will be applied to a workpiece; and   (iii) means for applying said ultra-high purity liquid treatment agent thus formed directly to a workpiece at said workstation; said production line, said conveying means and said subunit all being contained in an environment maintained free of contamination by said semiconductor manufacturing standards.       
     
     
       3. A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of a liquid treatment agent to said workpiece;   (b) means for conveying said workpiece to said workstations in succession along said production line; and   (c) a subunit adjoining said production line at said selected workstation to supply said liquid treatment agent in ultra-high purity form, said subunit supplied by raw materials including a gaseous raw material and comprising: (i) means for purifying said gaseous raw material to a purity compatible with semiconductor manufacturing standards . .defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes other than said raw material itself, a particulate content of less than about 150/cm 3  and a particle size of less than 0.2 micron, a microorganism content of less than about 10/ cm 3 , and total organic carbon of less than 100 ppb.!.;   (ii) means for combining said gaseous raw material so purified with further raw material of a purity compatible with said semiconductor manufacturing standards, under conditions such that said gaseous raw material and said further raw material are converted to said ultra-high purity liquid treatment agent at a rate approximately equal to that at which said liquid treatment agent will be applied to a workpiece, and such that said ultra-high purity liquid treatment agent is produced at a rate of from about 200 cc/h to about . .2L/h.!. .Iadd.2 1/h.Iaddend.; and   (iii) means for applying said ultra-high purity liquid treatment agent thus formed directly to a workpiece at said workstation; said production line, said conveying means and said subunit all being contained in an environment maintained free of contamination by said semiconductor manufacturing standards.       
     
     
       4. A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of a liquid treatment agent to said workpiece;   (b) means for conveying said workpiece to said workstations in succession along said production line; and   (c) a subunit adjoining said production line at said selected workstation to supply said liquid treatment agent in ultra-high purity form, said subunit supplied by raw materials including a gaseous raw material and comprising: (i) means for forming said gaseous raw material by electrolysis of a liquid   (ii) means for purifying said gaseous raw material to a purity compatible with semiconductor manufacturing standards . .defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes other than said raw material itself, a particulate content of less than about 150 cm 3  and a particle size of less than 0.2 micron, a microorganism content of less than about 10cm 3 , and total organic carbon of less than 100 ppb.!.;   (iii) means for combining said gaseous raw material so purified with further raw material of a purity compatible with said semiconductor manufacturing standards, under conditions such that said gaseous raw material and said further raw material are converted to said ultra-high purity liquid treatment agent at a rate approximately equal to that at which said liquid treatment agent will be applied to a workpiece; and   (iv) means for applying said ultra-high purity liquid treatment agent thus formed directly to a workpiece at said workstation; said production line, said conveying means and said subunit all being contained in an environment maintained free of contamination by said semiconductor manufacturing standards.       
     
     
       5. A system in accordance with claims 1, 2 or 3 in which said means for purifying said gaseous raw material is a fractional distillation column, a microfiltration or ultrafiltration membrane, or a combination thereof. 
     
     
       6. A system in accordance with claim 1, 2, 3 or 4 in which said further raw material is a member selected from the group consisting of ultra-high purity water, H 2  SO 4 , hydrogen gas and air. 
     
     
       7. A system in accordance with claims 1, 2, 3 or 4 in which said gaseous raw material is defined as a first gaseous raw material, and said further raw material comprises water plus a second gaseous raw material of a purity substantially equal to that of said first gaseous raw material. 
     
     
       8. A system in accordance with claims 1, 2, 3 or 4 in which said means for combining said gaseous raw material and said further raw material are positioned within approximately 30 cm of said means for applying said ultra-high purity liquid treatment agent to said workpiece, along said production line. 
     
     
       9. A system in accordance with claims 1, 2, 3 or 4 in which components (ii) and (iii) of said subunit are arranged for continuous or semicontinuous flow. 
     
     
       10. A system in accordance with claim 1, 2, 3 or 4 in which said further raw material is water having a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes, a particulate content of less than about 150/cm 3 , and a microorganism content of less than about 10/cm 3 . 
     
     
       11. A system in accordance with claims 1, 2, 3 or 4 in which said means for combining said gaseous raw material and said further raw material is a member selected from the group consisting of a mist contactor, a burner and a catalytic reactor. .Iadd. 
     
     
       12.  A system for the manufacture of a high-precision electronic component, said system comprising: a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of a liquid treatment agent to said workpiece;   a subunit connected through piping to at least one said workstation with no intervening exposure to less than ultra-clean environments, to supply said liquid treatment agent in ultra-high purity form, said subunit supplied by gaseous raw material selected from the group consisting of ammonia, hydrogen fluoride, hydrogen chloride, hydrogen bromide, phosphine, arsine, diborane and sulfur dioxide, and said subunit comprising: a first subsystem for purifying said gaseous raw material to a purity compatible with semiconductor manufacturing standards;   a second subsystem for combining said gaseous raw material so purified with further raw material of a purity compatible with said semiconductor manufacturing standards, under conditions such that said gaseous raw material and said further raw material are converted to said ultra-high purity liquid treatment agent at a rate approximately equal to that at which said liquid treatment agent will be applied to a workpiece; and   a connection for applying said ultra-high purity liquid treatment agent thus formed directly to a workpiece at said workstation. .Iaddend..Iadd.13. A system for the manufacture of high-precision electronic components, said system comprising:     a production line containing a plurality of workstations successively arranged for treating workpieces to be formed into said electronic components at least one said workstation applying a liquid treatment agent to said workpieces;   a purification station which generates said liquid treatment agent in ultrapure form, from starting materials which include deionized water and a gaseous component; and   an ultra-clean transfer line connected between said purification station and said one workstation, said transfer line providing a continuous flow path without exposure to less than ultra-clean environments, wherein a chemical withdrawn from said at least one said workstation is not the source of said gaseous component     
     
     
        starting material. .Iaddend..Iadd.14.  A method for providing an ultra-high-purity liquid chemical to a semiconductor manufacturing line which includes multiple workstations, comprising the steps of: generating said liquid chemical in ultrapure form, from starting materials which include ultrapure deionized water and a gaseous reagent; and   directly routing said liquid chemical produced by said generating step through an ultra-clean transfer line to one or more of said workstations in said manufacturing line, said transfer line providing a continuous flow path without exposure to less than ultra-clean environments, wherein said gaseous reagent is not obtained by reprocessing a chemical withdrawn from said one or more of said workstations. .Iaddend..Iadd.15. The system of claim 12, wherein said piping comprises stainless steel or high density polyethylene or a fluorinated polymer. .Iaddend..Iadd.16. The system of claim 12, wherein said first subsystem for purifying said gaseous raw material uses one or more of: fractional distillation, microfiltration, ultrafiltration, ion gettering, chromatographic extraction, electrodialysis or ion exchange. .Iaddend..Iadd.17. The system of claim 13, wherein said purification station uses one or more of: fractional distillation, microfiltration, ultrafiltration, ion gettering, chromatographic extraction,     
     
     
        electrodialysis or ion exchange. .Iaddend..Iadd.18.  The system of claim 13, wherein said transfer line comprises stainless steel or high density polyethylene or a fluorinated polymer. .Iaddend..Iadd.19. The system of claim 13, wherein said liquid treatment agent is selected from the group consisting of: aqueous hydrofluoric acid (HF);   aqueous ammonium fluoride (NH 4  F);   aqueous ammonium bifluoride (NH 4  HF 2 );   hydrogen peroxide;   aqueous nitric acid (HNO 3 );   fuming nitric acid (HNO 3 );   aqueous phosphoric acid (H 3  PO 4 );   sulfuric acid (H 2  SO 4 );   aqueous hydrochloric acid (HCl):   buffered oxide etch (BOE) and other aqueous combinations of ammonium fluoride and hydrofluoric acid;   aqueous combinations of hydrofluoric and nitric acids;   aqueous combinations of phosphoric and nitric acids;   aqueous combinations of sulfuric acid and hydrogen peroxide;   aqueous combinations of hydrochloric acid and hydrogen peroxide; and   aqueous combinations of ammonium hydroxide and hydrogen peroxide. .Iaddend..Iadd.20. The method of claim 14, wherein said transfer line comprises stainless steel or high density polyethylene or a fluorinated   
     
     
        polymer. .Iaddend..Iadd.21.  The method of claim 14, wherein said liquid chemical is selected from the group consisting of: aqueous hydrofluoric acid (HF);   aqueous ammonium fluoride (NH 4  F);   aqueous ammonium bifluoride (NH 4  HF 2 );   hydrogen peroxide;   aqueous nitric acid (HNO 3 );   fuming nitric acid (HNO 3 );   aqueous phosphoric acid (H 3  PO 4 );   sulfuric acid (H 2  SO 4 );   aqueous hydrochloric acid (HCl);   buffered oxide etch (BOE) and other aqueous combinations of ammonium fluoride and hydrofluoric acid;   aqueous combinations of hydrofluoric and nitric acids;   aqueous combinations of phosphoric and nitric acids;   aqueous combinations of sulfuric acid and hydrogen peroxide;   aqueous combinations of hydrochloric acid and hydrogen peroxide; and   aqueous combinations of ammonium hydroxide and hydrogen peroxide. .Iaddend..Iadd.22. The method of claim 14, wherein said generating step uses one or more of fractional distillation, microfiltration, ultrafiltration, ion gettering, chromatographic extraction,   
     
     
        electrodialysis or ion exchange. .Iaddend..Iadd.23.  The system of claim 12, further comprising an in-line reservoir connected to said piping. .Iaddend..Iadd.24. The system of claim 13, further comprising an in-line 
     
     
        reservoir connected to said transfer line. .Iaddend..Iadd.25.  A system for the manufacture of high-precision electronic components, said system comprising: a production line containing a plurality of workstations successively arranged for treating workpieces to be formed into said electronic components, at least one said workstation applying a liquid treatment agent to said workpieces;   a purification station which generates said liquid treatment agent in ultrapure form, from starting materials which include deionized water and a gaseous component, wherein the purification system comprises a deionized water introduction line and a gaseous component introduction line; and   an ultra-clean transfer line connected between said purification station and said one workstation,   said transfer line providing a continuous flow path without exposure to   
     
     
        less than ultra-clean environments. .Iaddend..Iadd.26.  The system of claim 25, wherein said purification station uses one or more of: fractional distillation, microfiltration, ultrafiltration, ion gettering, chromatographic extraction, electrodialysis or ion exchange. .Iaddend..Iadd.27. The system of claim 25, wherein, said transfer line comprises stainless steel or high density polyethylene or a fluorinated polymer. .Iaddend..Iadd.28. The system of claim 25, wherein said liquid treatment agent is selected from the group consisting of: aqueous hydrofluoric acid (HF);   aqueous ammonium fluoride (NH 4  F);   aqueous ammonium bifluoride (NH 4  H 2 );   hydrogen peroxide;   aqueous nitric acid (HNO 3 );   fuming nitric acid (HNO 3 );   aqueous phosphoric acid (H 3  PO 4 );   sulfuric acid (H 2  SO 4 );   aqueous hydrochloric acid (HCl);   buffered oxide etch (BOE) and other aqueous combinations of ammonium fluoride and hydrofluoric acid;   aqueous combinations of hydrofluoric and nitric acids;   aqueous combinations of phosphoric and nitric acids;   aqueous combinations of sulfuric acid and hydrogen peroxide;   aqueous combinations of hydrochloric acid and hydrogen aqueous combinations of ammonium hydroxide and hydrogen peroxide. .Iaddend..Iadd.29. The system of claim 25, further comprising an in-line reservoir connected to said   
     
     
        piping. .Iaddend..Iadd.30.  A method for providing an ultra-high-purity liquid chemical to a semiconductor manufacturing line which includes multiple workstations, comprising the steps of: generating said liquid chemical in ultrapure form, from starting materials which include ultrapure deionized water and a gaseous reagent, wherein the ultrapure deionized water and the gaseous reagent or the gaseous reagent after purification are brought into contact with each other; and   directly routing said liquid chemical produced by said generating step through an ultra-clean transfer line to one or more of said workstations in said manufacturing line,   said transfer line providing a continuous flow path without exposure to less than ultra-clean environments. .Iaddend..Iadd.31. The method of claim 30, wherein said transfer line comprises stainless steel or high density polyethylene or a fluorinated polymer. .Iaddend..Iadd.32. The method of claim 30, wherein said liquid chemical is selected from the g consisting of:   aqueous hydrofluoric acid (HF);   aqueous ammonium fluoride (NH 4  F);   aqueous ammonium bifluoride (N 4  HF 2 );   hydrogen peroxide;   aqueous nitric acid (HNO 3 );   fuming nitric acid (HNO 3 );   aqueous phosphoric acid (H 3  PO 4 );   sulfuric acid (H 2  SO 4 );   aqueous hydrochloric acid (HCl);   buffered oxide etch (BOE) and other aqueous combinations of ammonium fluoride and hydrofluoric acid;   aqueous combinations of hydrofluoric and nitric acids;   aqueous combinations of phosphoric and nitric acids;   aqueous combinations of sulfuric acid and hydrogen peroxide;   aqueous combinations of hydrochloric acid and hydrogen peroxide; and   aqueous combinations of ammonium hydroxide and hydrogen peroxide.   
     
     
        .Iaddend..Iadd.33.  The method of claim 30, wherein said generating step uses one or more of fractional distillation, microfiltration, ultrafiltration, ion gettering, chromatographic extraction, 
     
     
        electrodialysis or ion exchange. .Iaddend..Iadd.34.  A method for providing an ultra-high-purity liquid chemical to a semiconductor manufacturing line which includes multiple workstations, comprising the steps of: generating said liquid chemical in ultrapure form, from starting materials which include a liquid reagent and a gaseous reagent, wherein the gaseous reagent or the gaseous reagent after purification and the liquid reagent or the liquid reagent after purification are brought into contact with each other; and   directly routing said liquid chemical produced by said generating step through an ultra-clean transfer line to one or more of said workstations in said manufacturing line,   said transfer line providing a continuous flow path without exposure to less than ultra-clean environments. .Iaddend..Iadd.35. The method of claim 34, wherein said liquid chemical is selected from the group consisting of:   aqueous hydrofluoric acid (HF);   aqueous ammonium fluoride (NH 4  F);   aqueous ammonium bifluoride (NH 4  HF 2 );   hydrogen peroxide;   aqueous nitric acid (HNO 3 );   fuming nitric acid (HNO 3 );   aqueous phosphoric acid (H 3  PO 4 );   sulfuric acid (H 2  SO 4 ); aqueous hydrochloric acid (HCl);   buffered oxide etch (BOE) and other aqueous combinations of ammonium fluoride and hydrofluoric acid;   aqueous combinations of hydrofluoric and nitric acids;   aqueous combinations of phosphoric and nitric acids;   aqueous combinations of sulfuric acid and hydrogen peroxide;   aqueous combinations of hydrochloric acid and hydrogen peroxide; and   aqueous combinations of ammonium hydroxide and hydrogen peroxide. .Iaddend.