Production Mode BSIM3v3 Data Collection and Parameter Extraction

Introduction

BSIM3v3 is well suited for automatic measurement using auto probers and automatic parameter extraction. A number of customers are already using this capability in UTMOST to extract well over 50 high quality models per week. Automation is good because it insures that all models are obtained using the same measurement criteria and the same extraction sequence! This uniformity of extractions of a large quantity of models that can be obtained weekly is good news for modeling engineers wishing to obtain high quality model corners.

Environment Setup for Measurement and Extraction

The intention of this article is to describe how to create a setup and overcome some difficulties that arise from test die layouts.

Different device geometries are quite often layed out in different groups on the same test die. This gives rise to difficulties of inner die probing and proper logging of measured data.

All devices can be arbitrarily distributed throughout 12 groups, but each device must have a unique number less than 19. This means that inner die probing scheme using BSIM3 extraction routine followed by ALL_DC routines cannot measure more than 18 different geometries (not a limitation in BSIM3, when typically 12 to 14 geometries are really recommended). Lets consider a typical example:

 

Group 1Group 2 Group 3Group 4
Dev
1x
2x
3x
4 x
5 x
6
7 x

x=activated device

Inner die probing can be used only when the prober is setup in AUTO mode. The probing will be done automatically and the resulting log file and the MODEL STRATEGY screen will look like:

Group 1Group 2 Group 3Group 4
Dev
1 x
2 x
3 x
4 x
5 x
6
7 x
8
*
*
*
18 x
19 x
20 x
21 x
22 x
23 x
24
25 x

x=activated device

Notice that all devices from group1, group2 and group3 have moved to the last measured group4. Do not activate devices in group1, group2 and group3. If you do, UTMOST will wrongly attempt to measure them. Local optimization setup, SPAYN interface setup, global optimization setup, etc., is prepared by the user as if all devices were in group4 and measured from group4. Do not create measurement setups as they will be created automatically by copying them from the BSIM3 routine.
 


Figure 1. Model strategy setups for group1, group2,
and group3 as described in this article example.