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SKW 7-2 Metrology Guideline
General Guideline for Optical Measurement Sites
There are several different sampling plans to effectively characterize the CMP process at hand with varying degrees of quality and efficiency.

Generally, we recommend that first sampling plan with three dies to any customer who performs the measurements manually (e.g. Nanospec Manual Optical Measurement tool).

For those using automated tools (e.g. Thermawave Opti-Probe or KLA/Tencor UV1250, P-Series), we recommend the second sampling plan (medium quality) with eight sites in the up and down regions measured on five dies.

We have found that this plan provides the best trade-off between quality and efficiency (time and cost) to our customers. The remaining plan is largely for those interested in very detailed measurements of the wafers.
Manual Measurement Plan - 3 Up and 3 Down Sites on 3 Dies
Automated Medium Quality Plan
- 9 Up Sites and 8 Down Sites on 5 Dies
Automated High Quality Plan
- 22 Up Sites and 22 Down Sites on 5 Dies
PL Dedicated Plan - 12 Up Sites and 12 Down Sites on 5 Dies
Up / Down site (Cross Sectional View)
Manual Measurement Sampling Plan top
Site Information for Manual Measurement Plan
Site # Up Area Down Area Site
Density
(%)
Pitch
(um)
X (um) Y (um) X (um) Y (um)
1 2005 2000 2055 2000 10 -
2 14045 6000 14095 6000 90 -
3 14013 14000 14038 14000 50 50
* X, Y coordinates are relavant to lower left corner of each die.
* Site numbers proceed from left to right and down to up sturctures.
Automated Medium Quality Measurement Sampling Plan top
Locations for Medium Quality Measurement Plan
Site # Up Area Down Area Site
Density
(%)
Pitch
(um)
X (um) Y (um) X (um) Y (um)
1 2005 2000 2055 2000 10 -
2 10020 2000 10070 2000 40 -
3 14030 2000 14080 2000 60 -
4 14045 6000 14095 6000 90 -
5 10015 10000 10065 10000 30 -
6 14035 10000 14085 10000 70 -
7 14013 14000 14038 14000 50 50
8 18125 18000 18375 18000 50 500
9 18000 6000     100 -
* X, Y coordinates are relavant to lower left corner of each die.
* Site numbers proceed from left to right and down to up sturctures.
* Site 9 has 100% persent density, so there is only up area.
Automated High Quality Measurement Sampling Plan top
Locations for High Quality Measurement Plan
Site # Up Area Down Area Site
Density
(%)
Pitch
(um)
X (um) Y (um) X (um) Y (um)
1 2005 2000 2055 2000 10 -
2 6010 2000 6060 2000 20 -
3 10020 2000 10070 2000 40 -
4 14030 2000 14080 2000 60 -
5 18040 2000 18090 2000 80 -
6 3015 7000 3065 7000 30 -
7 7025 7000 7075 7000 50 -
8 11035 7000 11085 7000 70 -
9 14045 6000 14095 6000 90 -
10 2005 10000 2055 10000 10 -
11 6045 10000 6095 10000 90 -
12 10015 10000 10065 10000 30 -
13 14035 10000 10065 10000 70 -
14 18025 10000 18075 10000 50 -
15 10002.5 14000 10007.5 14000 50 10
16 14012.5 14000 14037.5 14000 50 50
17 18025 14000 18075 14000 50 100
18 2005 18000 2015 18000 50 20
19 6020 18000 6060 18000 50 80
20 10007.5 18000 10022.5 18000 50 30
21 14050 18000 14150 18000 50 200
22 18125 18000 18375 18000 50 500
PL(Planarization Length) Dedicated Plan top
Site # Up Area Down Area Site
Density
(%)
Pitch
(um)
X (um) Y (um) X (um) Y (um)
1 2005 2000 2055 2000 10 -
2 10020 2000 10070 2000 40 -
3 14030 2000 14080 2000 60 -
4 14045 6000 14095 6000 90 -
5 8515 10000 8565 10000 30 -
6 10015 10000 10065 10000 30 -
7 11515 10000 11565 10000 30 -
8 12535 10000 12585 10000 70 -
9 14035 10000 14085 10000 70 -
10 15535 10000 15585 10000 70 -
11 14013 14000 14038 14000 50 50
12 18125 18000 18375 18000 50 500
 
General Guide for Step Height Measurement top
Step height measurements are taken at the locations shown in the figure below.

Because of the low throughput and significant manual effort involved, step height measurements need only be taken at two die: one in the center and one near the outside.

The variation in step height across the wafer is typically the largest source of variation. Our specification for this is 5% or less.

For each of these die, the step height measurement is taken at four density locations: 10%, 50%, 70% and 90% density locations.

SKW has verified via SEM measurements on many lots that the variation in step height within a single die is less than 2%.

 
 

SKW Associates, Inc.