In this lesson, we will go through the steps of  creating 
Transmission Line Method test patterns.  Our goal to 
eventually create a mask, or have TLM patterns available 
as instance for future designs.

FIGURE 9:  TLM PATTERNS



Begin by opening the layout window for scratch.  Zoom out 
four times. The major and minor grid markings should disappear.

Go to the LSW.  Select nwell.

In the editing window, select create--rectangle. Pick a point 
near the left  side of the window to start your design.  As 
you move the mouse,

look at the column at the top of the window.  You see:

X: ------  Y: ------  (F) Select: 0    dx: -----  dY: ---- 
Dist: ----

When you initiate the rectangle, notice that the dX: and dY: 
jump to 0.0.  As you move the mouse away, these magnitudes 
increase. When dX reads 632, and dY is 390, click so that the 
rectangle is drawn.

Since TLM patterns are used to measure the contact resistance,
we must add contact cuts as well.  Select  cont.
We are going to draw a series of contact pads which are 80x80
microns in dimension. Near the top of the nwell, draw an  80x80 
square of cont.

Select edit--copy (or type "c").  Place the copy so that it 
is 5 microns away from the previous contact.  Make 4 more 
copies, and place each at 10,15,20, and 25 microns from its 
predecessor respectively.

Now, select ALL of the contact pads at the same time.  We are 
going to repeat this pattern 4 times.  Hit "c" for copy, and 
make your reference point the lower left corner of the row.  
Place the copy directly below the original row.  Do this two more
times.

The final step in the design is the addition of a metalization 
region.  Change the layer to metal1, and repeat the process
described for the contact cuts so that each contact square 
is covered by an 80x80 square of metal1.
  
At this point, we would like to save the scratch layout 
we have been working on as "TLM".  Click on Design--Save As.  
When the Save As form appears, type TLM in the cell name.  
Close the scratch window. Take care to NOT save this as scratch.

In the library browser, select TLM layout. Only a version 
0.0 should be present.  Select edit as earlier.   Your 
saved design is on the screen.

Before we update this to a version 0.1, we should move 
the origin out of the window so that it is not in our printouts.  
Select Misc--Move Origin. An outline of the axes follows 
the mouse.  Close to one of the corners, click the left 
buttons to confirm the placement.

Now, close this window.  Agree to saving any changes made.
Return to the Library Browser.  Move the mouse to the word 
tutorial, and click with the middle button.  A drop down 
menu appears. Choose "Show Checkouts".  A form appears 
with all the files you have saved.  Click the box next to 
TLM layout 0.0 (today's date).  Then click  OK.  In the 
library browser, click on TLM--layout.  A version  0.1 is 
now present.

****Whenever you have completed a design you should 
****check it in to an updated version.  Otherwise, 
***you will not be able to use it as an instance.