Hints, Tips and Solutions

How can I develop my own etch model in Victory Process?

Background: Victory Process is packaged with a wide range of etch models. Victory Process also supports an “Open Modelling Interface” (OMI). The OMI enables users to develop their own models inside Victory Process. Both etch and deposit models can be defined by the user in the OMI.

Example: In this example we are going to demonstrate how to define your own etch model.

Shown in Figure 1 is the starting structure.

The demonstration structure is a simple piece of silicon with uniform geometry in the y direction and simple stepped surface.

The etch model is a CMP style model which will control the etch rate as a function of distance from the surface. As such, the surface high point (left hand side of the structure) will etch at a higher rate than the lower point of the surface (right hand side of the structure).

The C interpreter file / code to create the etch model is shown below

/***********************************
* cmp_physical
* Comment: rate dependent on point’s
* distance to the
* top surface point
**************************************/
int
cmp_physical(double max_z,

double x, double y,
double z,
double r0,
double ratio0,
double* rate)

{

if ( z >= max_z )
{
*rate = r0
}
else
{
*rate = r0 -( max_z – z) *
ratio0;
}
return 0;

}

The first section of the file defines the inputs and output of the file.