nickel silicide process concern in SNF.
mdeal at stanford.edu
Wed Nov 3 09:38:36 PST 2004
At 09:19 AM 11/3/2004, you wrote:
>Great! Thanks! So, are there "official" semiclean B rules now (other
>than the wet bench concerns?) Are they ready enough to post to
>SpecMat? (And are there any plans for plasma etchers? I think this is
>where Jun has concerns...)
Here's what we decided a month or two ago:
>>Here is the current list of materials planned for the SCT:
>> Ni, Co, Pt, Al, Hf, Ta, Mo, W, Ti, Cr, Zr
>>All targets except for Pt, Zr, and Cr, are already here.
>>Al, W, and Ti are currently classified as "semi-clean." The others (Ni,
>>Co, Pt, Hf, Ta, Mo, and Cr, and Zr) are currently being studied and used
>>by our users and by industrial chip manufacturers as gate materials and
>>as silicides. So far, unlike Au, Cu, alkalai metals, etc., no harmful
>>effects have been seen on device performance with these
>>elements. However, we should still be careful with them in case
>>something may arise. In many cases, the users most sensitive to their
>>effects (i.e. those building CMOS devices) are the ones who are now
>>studying and using them. Jim and I are working with several of the
>>students who are using these materials and we will keep a close eye on this.
>>Here's what we propose:
>>1. Deposition of all metals in the SCT will be limited to 100nm (may be
>>increased to 200nm). This will limit the problems (peeling,
>>contamination, etc.) caused by excess deposition of these materials.
>>2. Al, Ti, and W will be classified as "semi-clean-A" and will be treated
>>as before in terms of what equipment wafers deposited with these elements
>>can go into subsequent to their deposition in the SCT. These include LTO
>>(tylanbpsg), tylanfga, wbsolvent, wbgeneral, wbmetal, wbsilicide as well
>>as many of the litho and etch equipment.
>>3. The other elements (Ni, Co, Pt, Hf, Ta, Mo, Cr, and Zr) will be
>>classified as "semi-clean-B." Wafers deposited with these elements in
>>the SCT can go into all the equipment listed in the semi-clean group,
>>EXCEPT for the etching systems. (Most can only be wet-etched anyway.)
>>Before we do this, however, Jim will look into any issues regarding the
>>use of wet benches and any possible cross-contamination that might occur
>>Finally, many of these materials already have some "special processing
>>rules" such as how any etching solution must be disposed of. These rules
>>will be continued.
More information about the specmat