JPS6148768A - Measuring method of contact resistance - Google Patents

Abstract

PURPOSE:To easily calculate contact resistance by forming plural groups of plural resistors which are nearly equal in shape and contact window (CW) and different in length and resistors which have CWs different in size and length on a semiconductor substrate. CONSTITUTION:Three groups A-C of resistors RA1-RA3, RB1-RB3, and RC1-RC3 having different lengths l1-l3 are formed on the semiconductor substrate; widths of the resistors in the respective groups are W1, W2, and W3 and the widths of CW parts are WCO1, WCO2, and WCO3. Resistance values of those resistors are measured and the lengths l1-l3 of the resistors are expressed as a function, and resistance values of lengths l1-l3 of display lengths are zero are calculated by extrapolation, and contact resistances RW1, RW2, and RW3 are calculated. Characteristic curves as functions of widths WCO1-WCO3 of CWs of contact resistances RW1-RW3 are obtained to easily calculate contact resistance to the width of an optional CW.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for measuring contact resistance of a resistor formed on a semiconductor substrate.

Conventional Structure and Its Problems FIG. 1 shows a simple plan view of a resistor fabricated on a semiconductor substrate. In the figure, 1 is a resistor, 2 and 3 are contact window portions, and 4 is a wiring portion. In FIG. 1, the width of the resistor is W, and the distance between the windows 2 and 3 formed in the resistor 1 is ? 2.
The sheet resistance of the resistor is ρ, and the contact windows 2 and 3
Letting the contact resistance generated at the contact surface between the wiring portion 4 and the wiring portion 4 be RH, the measured resistance value R of the resistor 1 is expressed by the following equation.

R= 2RH+ @ρ ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・(1) Normally, the contact resistance RH is sufficiently small compared to the resistance value of the resistor represented by Wρ, so when designing a mask, the contact resistance RH I often celebrate everything. However, if the resistance value of the resistor itself is small or if the relative ratio accuracy of the resistance becomes a problem, the contact resistance HHH1 cannot be ignored. In other words, if you want to improve the accuracy of circuit design, you will have to consider the contact resistance RH2 in advance, and you will need to calculate the contact resistance in some way. A calculation method was desired.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a measuring method that can extremely easily calculate a contact resistance that is suitable for the actual situation.

Composition of the Invention To summarize, the present invention is characterized in that a plurality of resistors having substantially the same shape and contact window portions and different lengths are formed on a semiconductor substrate, and the resistors have a size different from that of the plurality of resistors. After forming a plurality of sets of resistors having contact windows of the same size and having different lengths, the measured resistance value of the resistor is determined by the length of the resistor in the set of resistors having contact windows of the same size. The resistance value when the length of the resistor is zero is extrapolated using the display line connecting the display points, and the extrapolation point is calculated as the contact resistance value. This is a contact resistance measurement method in which contact resistance is measured in each set of resistors with different contact window sizes and the contact resistance value is detected according to the size of the contact window. According to this method, contact resistance can be measured extremely easily. In addition, the contact resistance when the contact window size is different can be estimated very easily.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows three sets of resistors with different sizes of contact windows formed on a semiconductor substrate according to an embodiment of the present invention, and FIG. 2 A, B, and C show the respective resistors. Body width is Wl
, W2. W, the width of the contact window is Wc01. WcO2
, WcO3. The same numbers are given to parts having the same functions as in FIG. 1. Next, the present invention will be explained. RA11RA2IRA3IRB11RB2IRB3 Three sets of resistors with different widths and different resistor lengths are located close to each other on the same semiconductor substrate and in the same direction.
After forming IRC1, RC2IRc3, their resistance values are measured.

Next, the length Il of the resistor, 1. g. , 23. The relationship between the width of the resistor and the measured value corresponding to the width of the contact window is shown in a graph as shown in FIG. Then, if we extrapolate the total resistance value of the resistor when the length of the resistor is zero for each contact window size, this point becomes the contact resistance value for any contact window size, and the third
In the figure, all Rw1. Rw2. It is called RVV3. Next, the width WcO of the contact window portion and the contact resistance RW1+RVl,! .

The relationship between RW3 is expressed in a graph as shown in Figure 4, f,
flLtba・Wc04(wCOlku”CO4kuWcO2
) If you want to find the contact resistance of , you can estimate it very easily by using Figure 4, and it will be a valuable resource when designing a circuit with high precision. That is, according to the present invention, the contact resistance for any width of the contact window can be determined directly or indirectly very easily.

As explained in the implementation section, the method for measuring contact resistance of the present invention has great utility value because it is extremely easy to calculate the contact resistance in accordance with the gas.

[Brief explanation of drawings]

Figure 1 is a plan view of a resistor built on a semiconductor substrate.
FIG. 2 is a plan view of a resistor solidly formed on a semiconductor substrate according to an embodiment of the present invention, and FIGS.
A graph for calculating the total contact resistance from a plurality of resistors shown in the figure is shown. 1... Resistor, 2, 3... Mountain contact window section, 4... Wiring section. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 3 Figure 4

Claims (1)

[Claims] A plurality of resistors having substantially the same shape and contact windows and different lengths are formed on a semiconductor substrate, and the contact windows have a different size from those of the plurality of resistors, and the lengths thereof After forming a plurality of sets of resistors having different contact windows, the measured resistance values of the resistors are displayed according to their lengths in the sets of resistors having contact windows of the same size, and this display point is Using the connecting display lines, extrapolate the resistance value when the length of the resistor is zero, calculate the extrapolation point as the contact resistance value, and apply the extrapolation method to the resistance value when the length of the resistor is zero. A method for measuring contact resistance, characterized in that the measurement is carried out for each pair, and the contact resistance value is detected according to the size of a contact window.