JPH07151800A - Resistivity measuring instrument - Google Patents

Abstract

PURPOSE:To improve the resistivity measuring efficiency of a resistivity measuring instrument without lowering the measurement accuracy of the instrument. CONSTITUTION:In a resistivity measuring device which measures the resistivity at a measuring point by lifting and lowering a measuring head 3, a motor 7 which lifts and lowers the head 3 and main control section 12 which controls the rotating speed of the motor 7 are provided and the impact to an object to be measured is reduced and the breakage of the object is prevented, and the lifting/lowering time of the head 3 is shortened while an improvement in the measurement accuracy is secured by reducing the acceleration of the head 3 at least immediately before the head 3 is stopped from a descending state and avoiding an abrupt reduction in speed. Therefore, the measuring efficiency of the measuring instrument can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistivity measuring device for measuring the resistivity of a semiconductor wafer in the process of manufacturing a semiconductor device.

[0002]

2. Description of the Related Art A conventional resistivity measuring device will be described with reference to FIG.

In the figure, 1 is a stage for receiving a wafer 2 and moving it in two horizontal directions, 3 is a specific resistance measuring head,
The specific resistance measuring head 3 is fixed to the tip of the elevating arm 4. The base end of the lifting arm 4 is a lifting slider 5
The lift slider 5 is mounted on a column 6 so as to be lifted and lowered. A cam 8 is fixed to a rotation shaft of a lifting motor 7 attached to the column 6, the cam 8 contacts a cam driven plate 9 of the lifting slider 5, and the cam driven plate 9 lifts the rotation of the cam 8. It is converted into a motion and transmitted to the elevating slider 5.

By rotating the cam 8 by the elevating motor 7, the specific resistance measuring head 3 moves up and down via the elevating slider 5 and the elevating arm 4. 3 shows the elevated state of the resistivity measuring head 3, and as shown in FIG. 4, the probe 10 of the resistivity measuring head 3 is moved by lowering the resistivity measuring head 3 by the lifting motor 7. The wafer 2 is brought into contact with the wafer 2 and the measurement of the specific resistance at one point is started. When the measurement of the resistivity at one point is completed, the lift motor 7 raises the resistivity measuring head 3, and the stage 1 moves the wafer 2 by a required amount.
Further, the specific resistance measuring head 3 is lowered to measure the specific resistance at the following points.

Moreover, the measurement of the specific resistance is performed at several tens to several hundreds of points on one wafer.

[0006]

As described above, the resistivity measurement is carried out at several tens to several hundreds of spots on one wafer. Therefore, the length of one measurement time is the efficiency of the resistivity measurement. Greatly affect the.

In the conventional resistivity measuring apparatus, the motor speed is not controlled, and the motor is rotated at a constant speed. Therefore, in order to shorten the measurement time at one point, the motor rotation speed must be increased. However, as the speed increases, the probe 1
The shock when 0 contacts the wafer 2 becomes large, and the damage on the surface of the wafer 2 becomes large. Damage to the surface of the wafer 2 leads to a decrease in the resistivity measurement accuracy, and there is a restriction that the rotation speed of the motor must be lower than a predetermined speed in order to ensure the measurement accuracy, which is a major limitation for improving the efficiency of the resistivity measurement. It was.

In view of the above situation, the present invention aims to shorten the measurement time at one point while preventing damage to the wafer surface, and improve the efficiency of resistivity measurement.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a resistivity measuring apparatus for raising and lowering a measuring head with respect to a measuring point to measure a specific resistance, a motor for raising and lowering the measuring head, and an increase or decrease of the motor speed. It is characterized in that it comprises a main control unit for controlling speed, and is configured to reduce at least deceleration acceleration before stopping to descend.

[0010]

[Function] At least the deceleration acceleration before descending and stopping is reduced to avoid a rapid decrease in speed, reduce the impact on the object to be measured, prevent damage to the object to be measured, and improve the measurement accuracy. The time required to move the measuring head up and down is shortened and the measurement efficiency is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an essential part of an embodiment according to the present invention. In FIG. 1, the same parts as those shown in FIG. 3 are designated by the same reference numerals. In the figure, 11 is the cam follower plate 9
Is a cam driven piece corresponding to.

The main controller 12 controls the motor controller 1
3. The elevating motor 7 can be driven through the motor driver 14, and the operation unit 15 is connected to the main control unit 12.

Information on the thickness of the wafer is input to the main controller 12 from the operation unit 15 and, as shown in FIGS.
Input the motor speed control information shown in.

Therefore, the descending position of the resistivity measuring head 3 is determined by the information on the thickness of the wafer, and regarding the motor speed control, the descending position of the resistivity measuring head 3 depends on the motor speed control of FIG. 2 (A). Information, and the rise of the specific resistance measuring head 3 is controlled by the information of the motor speed control of FIG. 2 (B).

When the specific resistance measuring head 3 is lowered by the motor speed control shown in FIG. 2A, the acceleration is increased at the start of the descent to shorten the time until the constant velocity state is reached and before stopping (probe). (Before 10 contacts the wafer 2), the speed is gradually reduced to reduce the impact when the probe 10 contacts the wafer 2.

Next, when the resistivity measuring head 3 is raised, there is no risk of damaging the wafer 2 by the probe 10, so the acceleration is increased at the start and before the stop to shorten the acceleration / deceleration time. Since only the speed of the probe 10 that influences the measurement before contacting the wafer 2 is reduced, the time required for moving the resistivity measuring head 3 up and down can be shortened.

Needless to say, the information on the motor speed control can be changed in various ways, and further, the information on the motor speed control is determined according to the shape of the cam. In the mode of deceleration at the time of descending, first, the speed may be rapidly reduced to a predetermined speed and then gradually decreased. Furthermore, although the above-described embodiments have been described with respect to the contact-type resistivity measuring device, it is needless to say that the non-contact-type resistivity measuring device can be similarly implemented.

[0019]

As described above, according to the present invention, it is possible to improve the measurement accuracy without increasing damage to the wafer, shorten the measurement time, and improve the efficiency of resistivity measurement. Becomes

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

2A and 2B are diagrams showing an example of motor speed control information.

FIG. 3 is an explanatory diagram showing a conventional specific resistance measuring device.

FIG. 4 is an explanatory diagram showing a conventional resistivity measuring device.

[Explanation of symbols]

 2 Wafer 3 Resistivity measuring head 7 Lifting arm 8 Cam 12 Main controller

Claims (1)

[Claims] 1. In a resistivity measuring device for raising and lowering a measuring head with respect to a measuring point to measure a specific resistance, a motor for raising and lowering the measuring head and a main control unit for controlling acceleration and deceleration of the motor speed. A resistivity measuring device comprising: