SU1226363A1 - Method of process inspection of mis-lsi element parameters - Google Patents

Abstract

The invention can be used to control MDP-LSIs during their production and operation. The purpose of the invention is to simplify control. In MDP-BIS, a ring generator is introduced. The frequency of the self-oscillations of the voltage of the test structure is measured, and the dynamic parameters of the LSI are judged by the frequency of the self-oscillations. Then, the oscillation frequency is lowered and, through the control system, the channel resistance values () and the threshold voltage (and ") are calculated. T Ad + A (/ „+ .Kk in„ + c ,, + b, and „c, where A„, A, A, AZ, B „, B, B, B are coefficients for which test values are selected structures in which U and R are close to their maximum and minimum values. Moreover, for and among the selected ones, and for 1, they are determined from test structures with values of -R., and .R and, R, T max values min. And t. Calculate the coefficients A and B by the known values of T, t, R and. The device, an implementation method, contains invertors 1-4 of the test structure of the MIS-BIS, a capacitor 5 for lowering the oscillation frequency, the meter 6 imp duration pulses and durations of the oscillation period. If the accuracy of measurements is necessary, the order of the equations can be increased to the second or third degree. 2 ill. § tv 1h с О О О .1

Description

This invention relates to a technique for controlling electrical parameters and can be used to control MIS-LSIs during their production and operation.

The purpose of the invention is to simplify control by eliminating the operations of removing and converting electrical signals characterizing static parameters.

The method consists in introducing a ring oscillator into the MDP-BIS, measuring the self-oscillation frequency of the test structure by the frequency of the self-oscillations judges the dynamic parameters of the LSI, reduces the oscillation frequency, calculates the channel resistance (R) and threshold voltage from the control system

T A. + A. P +

 H

1 В „+. B, and „+.„ + .R

to

Where

AT

AT

AT.

D d d d l

about - J 2. 3 about 1 at 3

coefficients found as follows: test structures are selected from which they are close to their maximum and minimum values, test structures are selected from those selected from which R are close to their maximum and minimum values, determined for test structures with Un R values ,

Tt, tt t ,, max k max

and. R, and Rn, and R ..

MiAij max GLSNXGLINCLKS

CALCULATE

min max

T and i values

the coefficients A and B are based on the known values of T, t, R, and u.

FIG. 1 shows a diagram of the device for implementing the method in FIG. 2 - the same, with additional resistors.

The device contains the first 1, second 2, third 3 and fourth 4 inverters of the test structure MDP-BIS, a capacitor 5 for lowering the oscillation frequency, a meter 6 pulse duration and the duration of the oscillation period. Inverters 1 - 3 are connected according to the scheme of the ring generator, inverter A is connected between the output of the ring generator and the meter 6.

The device works as follows.

First, an annular generator containing inverters 1 - 3 of the test structure is turned on, and through the inverter 4 of the test structure, the voltage oscillations of the ring generator are fed to a frequency meter 6.

263632

the measured frequency is judged on the dynamic parameters of inverters 1-3. Then, the oscillation frequency of tens of kilohertz of the ring oscillator is lowered, the capacitor 5 is connected between the input and output of the inverter 3. The period T of the oscillations and the duration i of positive polarity pulses are measured by the meter 6. Channel resistance R and threshold voltage are from the system of equations

ten

T, and "I,

 - about

L IS

15

+ B.U.

+ B, .i

.i „„

The equations are a model of T and V with and и and R. Because the model is difficult to calculate, the values of the coefficients A and B are experimentally determined as follows: measurement 1} in the totality of identical test structures and the selection of such samples in which Up values are close to their maximum and minimum values; measurement of R in the group of preselected samples of test structures and a new selection of such samples from which R values are close to their maximum

and minimum values; inclusion of selected samples of test structures

 so that, in space LU, R, four orthogonal points corresponding to the plan of the full factorial experiment, if necessary, include additional resistors 7-12 (Fig. 2) j measure Tis values at the four extreme parameters R and, calculate, the coefficients A and B of the equations for the known values of T, L, AI,.

If it is necessary to improve the accuracy of measurements, the order of equations can be increased to the second or third degree.

Claims (1)

Invention Formula The method of technological control of the parameters of the MDP-LSI elements, which consists in introducing a test structure in the form of a ring generator into the MDP-LSI, measuring the oscillation frequency of the test structure in the form of a ring generator introduced into the MDP-LSI, according to the oscillation frequency the dynamic parameters of the tested circuit, the static parameters are judged by the magnitude of the channel resistance and the threshold voltage, characterized in that, in order to simplify the control, which consists in reducing the number of operations, reduce the frequency of self-oscillations tens of kilohertz measured period of oscillation (T) and a pulse width (t), calculated by the channel resistance (R) and voltage threshold voltage (U) of the system of equations T, and, and „I I В „+ В, and„, to 26363. , four where L, A, -, A ,. AJ, B, B,, B ,,, B are scale factors, preselect test structures that have and close to their maximum and minimum values, test structures are selected from those that have R close to their maximum and the minimum values determined for the test. 0 structures with values and to „ and „RK UH RK and, R,, -   mitch gchoks tim (cin poppy the values of T and t and calculate the coefficient A and B from known values 1.1 and „„ Compiled V. Gusev Editor N. Yatsola Tehred I. Popovich Proofreader L. Patay   ..-- "- C - .P .-. M11-11D-1-. at, Order 2127/44 Circulation 728 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and psglygraphic enterprise, Uzhgorod, Projecto st., 4