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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Petz who wrote (34902)	7/21/1998 1:38:00 PM
From: MikeyB	Respond to of 1573310

Well, I couldn't find the picture either but ... "LI is shown like a W plug" - AMD's local interconnect uses a process similar to their tungsten (W) plug process. "CMP along with SOG..." - AMD uses a combination of these two processes to planarize the hell outa each layer.

To: Petz who wrote (34902)	7/21/1998 1:46:00 PM
From: Time Traveler	Respond to of 1573310

>>LI is shown like a W plug<< Local interconnects are not actual metal layers but something similar to tungsten plugs (connection joints between poly and metal or metal to metal). >>CMP along with SOG...<< SOG, spin on glass, is added to the chip to even out the bumps caused by metal traces. After SOG and a layer of metal interconnects are laid down, you cover the layer with some insulation material, termed ILD. You would still find bumps on top of the newly created layer. Then you use CMP, chemical mechanical polishing, to sand down the bumps to create a very even surface. So the next layer would go down easily just like the previous one, also to eliminate mechanical stressing of the metal traces. Of course, you cannot find the picture because it costs $50 (duh!!!), about three shares of your precious AMD stock. Why don't you send that company a check? Then, they will stuff your e-mail box with this JPEG file. You would know what Mickey and I are talking about. You're welcome, Time Traveler

To: Petz who wrote (34902)	7/21/1998 10:10:00 PM
From: Yousef	Read Replies (1) \| Respond to of 1573310

John, Re: "Explain the phrases "LI is shown like a W plug" There are two ways of "doing" Local Interconnect (LI) ... 1) Enlarge the contacts so that they cover from Poly to Source/Drain. Then when tungsten fill is done, the poly line is connected to the S/D ... 2) Put in two additional masking steps to pattern a dielectric and conductor layers. This has the advantage that LI can pass over a poly line and allow two S/D's to be connected without "shorting" to poly. This method is obviously much more complex and looks like a Metal 0 option. The issue with the first approach is that now you have contacts of different sizes (without LI, all contacts are the same size) ... contacts of different size etch at different effective rates (smaller contacts etch slower). Thus control of the contact etch can be an issue. Hope this helps. Make It So, Yousef