Patent US4557948A successfully refreshed from Google Patents.
US5489540A
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Method of making simplified LDD and source/drain formation in advanced CMOS integrated circuits using implantation through well mask
Assignee: Advanced Micro Devices Inc
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Filing: 1995-03-22
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Granted: 1996-02-06
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Expires: 2015-03-22
Abstract
Abstract A novel CMOS fabrication process that eliminates several masks of a conventional process by delaying application of a well mask to a semiconductor structure until after formation of isolation regions and gate structures. Providing for three separate implant steps and selectively implanting dopants through an exposure window of the well mask, through gate structures, and through the well mask allows formation of the well region, and source/drain regions in the well region, and in the region covered by the well mask. When LDD implants are desired, removal of a lateral spacer on the gate overlying the well region and subsequent LDD implant through the mask region introduces the LDD implant. Separate masks for source/drain regions and LDD regions are not required. In an alternate embodiment, the LDD implant is introduced prior to formation of lateral spacers on gate structures and application of the well mask, providing the LDD implant in both channels, and eliminating a requirement for lateral spacer removal.
Inventors
- 👤 Yowjuang W. Liu
- 👤 Kuang-Yeh Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:36
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0191; H10D84/02; H10D84/03; H10D84/038; Y; Y10; Y10S; Y10S438/00; Y10S438/965
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
217 words
A method for forming a complementary metal oxide semiconductor (CMOS) structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter masking said first active region with a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of a first conductivity type through said exposure window and said second gate into said substrate to create a well region of said first conductivity type, said well region having a depth contour; implanting dopants of a second conductivity type through said exposure window to form a source region and a drain region in said second active region that are each latterly disposed away from said gate in said second active region; and implanting dopants of said first conductivity type through said exposure window to shape said depth contour and through said well mask to form a source region and a drain region in said first active region that are each latterly disposed away from said gate in said first active region.
Claim 2
Independent Claim
217 words
A method for forming a complementary metal oxide semiconductor (CMOS) structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter masking said first active region with a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of a first conductivity type through said exposure window and said second gate into said substrate to create a well region of said first conductivity type, said well region having a depth contour; implanting dopants of a second conductivity type through said exposure window to form a source region and a drain region in said second active region that are each latterly disposed away from said gate in said second active region; and implanting dopants of said first conductivity type through said exposure window to shape said depth contour and through said well mask to form a source region and a drain region in said first active region that are each latterly disposed away from said gate in said first active region.
Claim 3
Dependent Claim
66 words
The structure forming method of claim 1 further comprising the steps of: forming a lateral spacer on each gate after said gate forming steps; thereafter removing said lateral spacer on said gate in said second active region after said implanting step; and thereafter forming a lightly doped drain in said second active region by implanting dopants of said second conductivity type into said second active region.
Claim 4
Dependent Claim
22 words
The CMOS forming method of claim 2 wherein said well mask is removed after said step of forming said lightly doped drain.
Claim 5
Dependent Claim
15 words
The structure forming method of claim 1 wherein said substrate is said first conductivity type.
Claim 6
Dependent Claim
14 words
The structure forming method of claim 1 wherein said first conductivity type is p-type.
Claim 7
Dependent Claim
13 words
The structure forming method of claim 5 wherein second conductivity type is n-type.
Claim 8
Dependent Claim
55 words
The structure forming method of claim 1 wherein said well region implanting step comprises the step of implanting boron dopants having a dose in a dose range of about 1×10 12 /cm 2 to about 1×10 14 /cm 2 and a dose energy in an energy range of about 25 keV to about 150 keV.
Claim 9
Dependent Claim
56 words
The structure forming method of claim 1 wherein said first active source/drain implanting step comprises the step of implanting boron dopants having a dose in a dose range of about 5×10 14 /cm 2 to about 5×10 16 /cm 2 and a dose energy in an energy range of about 100 keV to about 300 keV.
Claim 10
Independent Claim
241 words
A method for forming a complementary metal oxide semiconductor structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter forming a lightly doped drain in said second active region by implanting dopants of a first conductivity type into said second active region and said first active region; and thereafter forming a lateral spacer on each of said gates; thereafter masking said first active region to provide a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of a second conductivity type through said exposure window into said substrate to create a well region of said second conductivity type; implanting dopants of said first conductivity type through said exposure window to form a source region and a drain region in said second active region that are each latterly disposed away from said gate in said second active region; and implanting dopants of said second conductivity type through said exposure window and through said well mask to form a source region and a drain region in said first active region that are each latterly disposed away from said gate in said first active region.
Claim 11
Independent Claim
241 words
A method for forming a complementary metal oxide semiconductor structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter forming a lightly doped drain in said second active region by implanting dopants of a first conductivity type into said second active region and said first active region; and thereafter forming a lateral spacer on each of said gates; thereafter masking said first active region to provide a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of a second conductivity type through said exposure window into said substrate to create a well region of said second conductivity type; implanting dopants of said first conductivity type through said exposure window to form a source region and a drain region in said second active region that are each latterly disposed away from said gate in said second active region; and implanting dopants of said second conductivity type through said exposure window and through said well mask to form a source region and a drain region in said first active region that are each latterly disposed away from said gate in said first active region.
Claim 12
Independent Claim
241 words
A method for forming a complementary metal oxide semiconductor structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter forming a lightly doped drain in said first active region by implanting dopants of a first conductivity type into said first active region and said second active region; and thereafter forming a lateral spacer on each of said gates; thereafter masking said first active region to provide a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of said first conductivity type through said exposure window into said substrate to create a well region of said first conductivity type; implanting dopants of a second conductivity type through said exposure window to form a source region and a drain region in said second active region that are each laterally disposed away from said gate in said second active region; and implanting dopants of said first conductivity type through said exposure window and through said well mask to form a source region and a drain region in said first active region that are each laterally disposed away from said gate in said first active region.
Claim 13
Independent Claim
241 words
A method for forming a complementary metal oxide semiconductor structure, comprising the steps of: forming, in a substrate, a first active region and an second active region separated from said first active region by an isolation region; thereafter forming a first gate overlying a portion of said first active region; and forming a second gate overlying a portion of said second active region; and thereafter forming a lightly doped drain in said first active region by implanting dopants of a first conductivity type into said first active region and said second active region; and thereafter forming a lateral spacer on each of said gates; thereafter masking said first active region to provide a well mask having an exposure window to expose said second active region and a portion of said isolation region; thereafter implanting dopants of said first conductivity type through said exposure window into said substrate to create a well region of said first conductivity type; implanting dopants of a second conductivity type through said exposure window to form a source region and a drain region in said second active region that are each laterally disposed away from said gate in said second active region; and implanting dopants of said first conductivity type through said exposure window and through said well mask to form a source region and a drain region in said first active region that are each laterally disposed away from said gate in said first active region.
Claim 14
Dependent Claim
57 words
The structure forming method of claim 10 further comprising the steps of: removing said lateral spacer on said gate in said second active region after said second conductivity type dopant implanting step; and thereafter forming a lightly doped drain in said second active region by implanting dopants of said second conductivity type into said second active region.
References Cited (Backward Citations)
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