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 semi-conductor 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, 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; 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. 
     
     
       12. 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 dionized water and a solid 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. 
     
     
       13. The method of  claim 12 , wherein the ultrapure deionized water and the solid reagent are brought into contact with each other. 
     
     
       14. The method of  claim 12 , 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. 
     
     
       15. 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 plurality of gaseous reagents; 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. 
     
     
       16. The method of  claim 15 , wherein said plurality of gaseous reagents are brought into contact with each other and form a reaction product. 
     
     
       17. The method of  claim 15 , further comprising condensing said reaction product. 
     
     
       18. The method of  claim 15 , 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.