Knocking Out Openings in our Mask

The Unit Cell Design

The Wafer/Die Settings

Matching Existing Die

Generating the Array
with GDS-SR

Plating on RDL/UBM

Clip to a Round Boundary

Knocking Out Openings

Dropping in the FIDS

Solder Stencil Issues

Knocking Out Openings in Our Mask

There are several places in our array of RDL circuits where we have to open up the mask so that underlying identification and alignment targets are visible. Normally the mask designer gets a list of window locations and sizes. HExtract can automate this process also to avoid hand editing.

We have a total of 6 openings to create:

NAME      LLX         LLY          URX         URY
WAFER_ID  3100.000,   92520.000,   16750.000,  95650.000
FID1     -9870.000,   94060.000,   -7700.000,  95670.000
FID2       7700.000, -95670.000,    9870.000, -94060.000
ALIGN1   -82695.390,  50150.000,  -81195.390,  51650.000
ALIGN2   -82695.390, -51650.000,  -81195.390, -50150.000
ALIGN3    81195.390,  50150.000,   82695.390,  51650.000

Again we will have HEXtract clip them smoothly so that the RDL and UBM layer do not suffer to much metal density variations.

HEXtract Command Line Syntax

We'll create a simple batch file that calls HEXtract 5 times -- once for each layer. However because there are so many cutouts, we will use an include file to list the cutouts.

Here is the contents of the include file, cutouts.txt

  # MASK CUTOUTS
  # LLX        LLY          URX         URY
  # WAFER_ID
  3100.000,    92520.000,   16750.000,  95650.000
  # FID1
  -10320.000,   93410.000,   -8150.000,  95020.000
  # FID2
 8150.000,    -95020.000,    10320.000, -93410.000
  # ALIGN1
  -82695.390,  50150.000,  -81195.390,  51650.000
  # ALIGN2
  -82695.390, -51650.000,  -81195.390, -50150.000
  # ALIGN3
  81195.390,   50150.000,    82695.390, 51650.000

Here is an annotated command line for one mask

   c:\wcad\hextract\hxtractor32.exe      <- launches the hextract program

      via1_after_clip.gds                <- the input file

        via1_bf_targets.gds               <- the output file

          -layers:1                      <- only process layer 1 (ourVIA1)

            -complement                  <- forces the cutout option

               -windows@cutouts.txt      <- gets cutout list from file ...

We'll repeat the same command line changing the file names and layers each time. The only difference will be on the solder mask layer. For that layer we will use the additional option -drop_partial_poly.

hxtractor32.exe   via1_after_clip.gds   via1_bf_targets.gds   -layers:1 
-complement -windows@cutouts.txt

hxtractor32.exe   rdl_after_clip.gds    rdl_bf_targets.gds    -layers:2 
-complement -windows@cutouts.txt

hxtractor32.exe   via2_after_clip.gds   via2_bf_targets.gds    -layers:3 
-complement -windows@cutouts.txt

hxtractor32.exe   ubm_after_clip.gds    ubm_bf_targets.gds     -layers:4 
-complement -windows@cutouts.txt

hxtractor32.exe   solder_after_clip.gds solder_bf_targets.gds  -layers:5 
-complement -windows@cutouts.txt -drop_partial_poly

Here is what the RDL layer looks like after knockouts generated by HExtract:

top section of wafer ...

zoomed in ...

zoomed in again ...

If you'd like to examine the GDSII files after the
target and fid windows have been knocked out,
click on the file below:

masks_bf_targets.zip GDSII Stream Zipped (4 MB)

NEXT Dropping in FIDS and Targets with GDSFILT ...