by the way .
I 'm not sure if it 's just really laggy or what 's going on there .
You 're not seeing the title slide ?
Now I 'm seeing the title slide .
I 'm going to go ahead and unmute myself .
Yeah , I don 't know if there 's anything we do about that either .
That 's got to be like a Zoom or potentially an Internet thing .
Well , let 's go ahead and do this
and then if I see that things look really janky ,
I might be messaging you .
But I think for the most part ,
if you just maybe take a quick pause between slides ,
we 'll be okay .
I 'll go ahead and mute ,
and then you can go ahead and get started , Tom .
I 'm really glad to be here today and presenting to you .
I 'll be discussing Chemical Mechanical Planarization or CMP .
This is an integral step in the semiconductor manufacturing process
that I will give a little bit of background on
as I move through my slides .
Let 's go to the first slide of the presentation .
Quick overview of CMP .
Once again , that stands for Chemical Mechanical Planarization ,
and that describes the two processes involved
with planarizing certain layers of circuits in the semiconductor field .
It 's crucial to planarize each layer of circuits
so that the one that goes on top of the preceding layer
will not have any shorts or opens or short circuits .
The chemical part of chemical mechanical planarization
is when we introduce a liquid
to react with the top atomic layer of the material that we are planarizing .
That reaction softens the layer ,
whether it 's a metal or an oxide , whatever the case may be ,
we choose that chemical so that it will soften the top atomic layer .
Then the mechanical part comes
with the abrasives that are carefully selected for that polishing slurry .
These abrasives then remove that softened top layer ,
exposing the next atomic layer to be softened by the chemical reaction .
This process is repeated atomic layer after atomic layer
until the desired level of planarization is reached .
Like I was saying ,
this planarization is crucial to do in between each layer of circuitry
to ensure that we have solid electrical isolation
without any shorts or opens .
This process enables us to pile many layers on top of one another
and reduce the footprint of whatever chip we 're making .
When we do the CMP processes ,
many of them consist of a two polish table process to enable maximum throughput .
Typically , the first table consists of a bulk polish
where most of a substance is planarized and removed ,
and then a final polish or second polish table
where we do the final touch -ups
and ensure that we have good electrical isolation between the circuits .
Each polish table has a polish pad
where we press the wafer containing the chips against ,
and this enables the polish process to occur
and it enables the slurry to be pressed against the wafer that contains the chips .
The polish pad , unfortunately ,
it wears down as each wafer is polished on it ,
which inhibits the transport of this chemical slurry to the wafer surface .
Typically , as the polish pad wears , we see a reduction in polish rate ,
which causes longer and longer polish times .
If we don 't take that wear factor into account
and we 're setting up the two -table process ,
then we will have one polish table begin to predominate ,
and it can actually develop such a long polish time
that it will become a limiting factor in our throughput .
For my presentation today ,
I 'm explaining a process whereby we can take into account the pad wear rate
and still ensure that we have optimized throughput .
Approach and the results .
I gathered and analyzed data in JMP
to show the polish time versus polish pad life relationship
for tables 1 and 2 for a CMP two -table process
at one of Texas Instruments Fabrication Facilities .
I then used JMP scripting language ,
the built -in integration function to calculate the area
under the polish time versus pad life curve for both tables .
Then , finally , I used the system of equations
to solve for a Table 1 polish time starting point
that enabled equal polish time versus polish pad life integrated areas
for tables 1 and 2 .
This ensured that we had achieved a maximized tool output
for the CMP process .
Conclusions are that we can use JMP
to develop , first of all , polish time versus polish pad life curves .
Then , second , we can use JMP scripting languages , built -in integrator .
We can use this combination
as an efficient way to optimize CMP two table processes for throughput .
Let 's go to the next slide .
This curve that we 're looking at is what we get when we plot the polish time
on the first table versus the polish pad life of that first table .
As we can see , the polish time as the pad wears
and we polish more and more wafers on this polish pad ,
we start to see polish times increase quite dramatically .
Using JMP , we can fit a line to this data
and develop a simple Y equals Mx plus b slope intercept function to fit this data .
I 'm using a first order here ,
but if the data justified it , we could use a second or third order .
But in this case , a first order is sufficient .
We developed the equation for polish time versus pad count ,
and then we use the JSL integrator to integrate the area under this line .
That 's for the Polish Table 1 .
Then I 'll talk a little bit more about the equations needed to solve
for the optimal settings .
But first of all , we 'll jump to Polish Table 2 .
Polish Table 2 is the final , it 's the finishing table
where we finish removing whatever the bulk material is
we 're using to isolate or form these circuits , electrical circuits .
The same thing for Polish Table 2 ,
we developed the curve from historical data
of polish time in seconds versus the polish pad life .
Typically , for the polishing plat , for the final plat or final table ,
the trend with polish pad life is not as pronounced as it is
for the bulk for Table 1 .
Before discussing a little bit more about these equations ,
just to make sure everyone 's on the same page ,
I wanted to show what physically this looks like on the wafer surface
for doing this two -table polish process .
Before we start to polish anything ,
we have a wafer with pattern circuits on it .
Then , on top of that wafer ,
we 've deposited a large amount , relatively speaking ,
of whether it 's isolator or electrically conductive material ,
whatever is needed to form the circuits that we 've etched here .
After Polish Table 1 , also known as the bulk polish table ,
we 've removed a significant amount of this bulk material
and we 've planarized it , made it very flat .
Then after Polish Table 2 ,
which is also called the clear or the finish table ,
we 've removed all of this bulk material
except where it 's actually needed in the pattern circuits .
Physically , that 's what 's happening in this two polish table process .
Let 's go back quickly to the equations .
We integrate the area under Table 1 , which is on the preceding slide .
That 's the bulk polish time versus Table 1 polish pad count .
Then we also integrate the area under this curve ,
which is the final or finish table .
Same thing , integrate the area under the polish time versus pad count line .
Then we solve the linear system of equations to find which Y -intercept ,
in this case , it 's b1 , and that 's for the Table 1 .
We solve for that b1 that will create an equal integrated area
under the Table 1 and the Table 2 curves .
Just as a reminder ,
the JMP scripting language has a handy function
for enabling quick integration
and determining the areas under these two curves .
Then based on a few other properties
that we know based on historical or baseline analysis ,
then we 're able to set up a system of equations
with four unknowns , four equations ,
and then we solve for that intercept on the first curve
that enables maximum throughput in equal area under these curves .
With that ,
almost the entire process can be done in JMP ,
with the exception of solving a system of equations
that can indirectly be done in JMP , or you can write a script .
But I 've found it easier just to solve the system of equations manually ,
but it could easily be set up to be done in JMP as well .
When you finish this process ,
then you 're able to optimize this two -table CMP system
and you can maximize the throughput
and so minimize the number of polish tools required ,
which saves a lot of money and saves a lot of time .
That is the end of my presentation .
Thank you .
