From kgc at stanford.edu  Fri Jun  1 10:04:19 2012
From: kgc at stanford.edu (Katie Chang)
Date: Fri, 1 Jun 2012 10:04:19 -0700
Subject: Question: Thickness variations across wafer?
Message-ID: <CAAnEngkOePojWKv_wvMGNojWAQy4b342xdf6vJSQS77FkkT+Ag@mail.gmail.com>

Hello Metalica users,

I have a question for the other users who sputter very thin layers of
metal. I know that, for small amounts of deposited metals, the center of
the wafer gets a slightly thicker layer than the edges, with a roughly
Gaussian thickness profile. Has anyone ever quantified this variation for
very thin layers (<30nm)?

We are trying to put down an extremely thin (5nm) layer of Au, and are
concerned about variations in thickness. We are especially interested in
Au, although any information about thickness profiles might have would
definitely be helpful.

Thanks, everyone! Happy sputtering,

--Katie
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From jimkruger at yahoo.com  Fri Jun  1 10:40:45 2012
From: jimkruger at yahoo.com (jim kruger)
Date: Fri, 1 Jun 2012 10:40:45 -0700 (PDT)
Subject: Question: Thickness variations across wafer?
In-Reply-To: <CAAnEngkOePojWKv_wvMGNojWAQy4b342xdf6vJSQS77FkkT+Ag@mail.gmail.com>
References: <CAAnEngkOePojWKv_wvMGNojWAQy4b342xdf6vJSQS77FkkT+Ag@mail.gmail.com>
Message-ID: <1338572445.60282.YahooMailNeo@web163101.mail.bf1.yahoo.com>

Metallica is not very uniform.? I measure 25 or 30% thickness variation, center thick, edge thin over a 100 mm wafer.
I don't think this number varies much with material or deposited thickness, I have seen it for every material and thickness I have checked.

? ? ? Just as average dep rate varies with the depth of the target erosion, the uniformity may vary some.? The dep rate change with erosion is because the thinner areas on the target have a stronger magnetic field so the plasma is more intense there.

jimkruger



________________________________
 From: Katie Chang <kgc at stanford.edu>
To: metalica at snf.stanford.edu 
Sent: Friday, June 1, 2012 10:04 AM
Subject: Question: Thickness variations across wafer?
 

Hello Metalica users,

I have a question for the other users who sputter very thin layers of metal. I know that, for small amounts of deposited metals, the center of the wafer gets a slightly thicker layer than the edges, with a roughly Gaussian thickness profile.?Has anyone ever quantified this variation for very thin layers (<30nm)??

We are trying to put down an extremely thin (5nm) layer of Au, and are concerned about variations in thickness. We are especially interested in Au, although any information about thickness profiles might have would definitely be helpful.

Thanks, everyone! Happy sputtering,

--Katie
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From sebastian.j.osterfeld at magarray.com  Fri Jun  1 10:41:59 2012
From: sebastian.j.osterfeld at magarray.com (Sebastian Jeremias Osterfeld)
Date: Fri, 1 Jun 2012 10:41:59 -0700 (PDT)
Subject: Question: Thickness variations across wafer?
In-Reply-To: <CAAnEngkOePojWKv_wvMGNojWAQy4b342xdf6vJSQS77FkkT+Ag@mail.gmail.com>
Message-ID: <1130076914.12009353.1338572519333.JavaMail.root@zm06.stanford.edu>

Hi Katie, 

I have done 10nm occasionally and did not perceive any issues with uniformity on Metalica. 

Some people in our lab use an optical density meter to check the (relative) thickness reproducibility of very thin metal layers that were deposited on a glass coupon. So my suggestion would be to deposit a 5nm film of Au on a glass wafer, and assuming that this is still partially transparent, I can show you where to test it for across-wafer uniformity (and run to run reproducibility) with the optical density meter. I think you don't even need to dice the wafer, this meter operates similar to a Dektak with whole wafers. 

If you go this route, it would be great if you could make the uniformity data available to other Metalica users. 

Best regards, 
Sebastian 

----- Original Message -----

> From: "Katie Chang" <kgc at stanford.edu>
> To: metalica at snf.stanford.edu
> Sent: Friday, June 1, 2012 10:04:19 AM
> Subject: Question: Thickness variations across wafer?

> Hello Metalica users,

> I have a question for the other users who sputter very thin layers of
> metal. I know that, for small amounts of deposited metals, the
> center of the wafer gets a slightly thicker layer than the edges,
> with a roughly Gaussian thickness profile. Has anyone ever
> quantified this variation for very thin layers (<30nm)?

> We are trying to put down an extremely thin (5nm) layer of Au, and
> are concerned about variations in thickness. We are especially
> interested in Au, although any information about thickness profiles
> might have would definitely be helpful.

> Thanks, everyone! Happy sputtering,

> --Katie
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From jperez at snf.stanford.edu  Fri Jun  1 14:52:17 2012
From: jperez at snf.stanford.edu (Jeannie Perez)
Date: Fri, 01 Jun 2012 14:52:17 -0700
Subject: Question: Thickness variations across wafer?
In-Reply-To: <1338572445.60282.YahooMailNeo@web163101.mail.bf1.yahoo.com>
References: <CAAnEngkOePojWKv_wvMGNojWAQy4b342xdf6vJSQS77FkkT+Ag@mail.gmail.com> <1338572445.60282.YahooMailNeo@web163101.mail.bf1.yahoo.com>
Message-ID: <4FC93991.3020604@snf.stanford.edu>

I have six data points, three for Target A and three for Target B _for 
this yea_r.  I use the same Aluminum targets each time on the same 
source guns. Measurements off Alpha step after
lift off is in the range of 20 to 25 %. My measurements may be slightly 
better, is due to that I am the only user of the targets and the erosion 
isn't to far off from the last time I used them.
My thickness is targeted for 1000A.
Jeannie
On 6/1/2012 10:40 AM, jim kruger wrote:
> Metallica is not very uniform.  I measure 25 or 30% thickness 
> variation, center thick, edge thin over a 100 mm wafer.
> I don't think this number varies much with material or deposited 
> thickness, I have seen it for every material and thickness I have checked.
>       Just as average dep rate varies with the depth of the target 
> erosion, the uniformity may vary some.  The dep rate change with 
> erosion is because the thinner areas on the target have a stronger 
> magnetic field so the plasma is more intense there.
>
> jimkruger
>
> ------------------------------------------------------------------------
> *From:* Katie Chang <kgc at stanford.edu>
> *To:* metalica at snf.stanford.edu
> *Sent:* Friday, June 1, 2012 10:04 AM
> *Subject:* Question: Thickness variations across wafer?
>
> Hello Metalica users,
>
> I have a question for the other users who sputter very thin layers of 
> metal. I know that, for small amounts of deposited metals, the center 
> of the wafer gets a slightly thicker layer than the edges, with a 
> roughly Gaussian thickness profile. Has anyone ever quantified this 
> variation for very thin layers (<30nm)?
>
> We are trying to put down an extremely thin (5nm) layer of Au, and are 
> concerned about variations in thickness. We are especially interested 
> in Au, although any information about thickness profiles might have 
> would definitely be helpful.
>
> Thanks, everyone! Happy sputtering,
>
> --Katie
>
>

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From ytcheng at stanford.edu  Tue Jun  5 18:49:30 2012
From: ytcheng at stanford.edu (Yao-Te Cheng)
Date: Tue, 5 Jun 2012 18:49:30 -0700
Subject: metalica free 6:30-9:30AM tomorrow
Message-ID: <000301cd4386$9dc82270$d9586750$@stanford.edu>

 

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From ytcheng at stanford.edu  Thu Jun  7 19:19:36 2012
From: ytcheng at stanford.edu (Yao-Te Cheng)
Date: Thu, 7 Jun 2012 19:19:36 -0700
Subject: metalica free 12-3pm tomorrow
Message-ID: <001e01cd451d$27099540$751cbfc0$@stanford.edu>

 

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From chen0622 at yahoo.com  Mon Jun 11 17:09:16 2012
From: chen0622 at yahoo.com (Chih-Chang Chen)
Date: Mon, 11 Jun 2012 17:09:16 -0700 (PDT)
Subject: metalica reservation released tomorrow from 9:30 AM to 1:00 PM
Message-ID: <1339459756.49189.YahooMailNeo@web161604.mail.bf1.yahoo.com>

Sample not ready.?
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From snf at purkl.net  Fri Jun 15 21:41:34 2012
From: snf at purkl.net (Fabian Purkl)
Date: Fri, 15 Jun 2012 21:41:34 -0700
Subject: metalica reservation released tomorrow Sun 8am-10am eom
Message-ID: <294a5e430365284b7453757fe23885fb-EhVcXlhARwtdRw8RGDpQCEFddQZLVF5dQUNBBjBTUF5bVkYBW0F3AFI6XFxcSE0AXlxQRA==-webmailer2@server03.webmailer.hosteurope.de>