JP7374682B2 - Resistivity measuring instrument, semiconductor device manufacturing method, and resistivity measuring method - Google Patents

Description

The present disclosure relates to a resistivity measuring device and a method for manufacturing a semiconductor device.

A semiconductor wafer resistivity measurement device measures the resistivity of a silicon wafer, the resistivity of an epitaxial wafer formed on the wafer surface, and the sheet resistance of a diffusion layer or injection layer when impurities are diffused or implanted from the surface and generated on the surface. This is a device that measures the sheet resistance, etc. of metal films that have been processed, and the measurement results are fed back to the process conditions of each semiconductor manufacturing equipment, making it an important measuring device for maintaining uniform quality of semiconductor devices. Such measuring devices include Patent Document 1 and Patent Document 2.

For example, Patent Document 1 states, ``The probe vertical drive section has a probe mounting bracket, a cam receiver, a stepping motor, and the tip of the cam receiver is always kept in contact with the probe mounting bracket to reduce the weight of the probe mounting bracket onto the axis of the stepping motor. A vertical drive cam supported by the stepping motor is disposed, and the control unit rotates the stepping motor shaft and the vertical drive cam at a speed and angle determined according to desired control information, and controls the vertical position of the four-point probe. "The contact state of the probe is configured to be set to a desired contact state depending on the type of semiconductor wafer." In addition, Patent Document 2 states that ``a plurality of four-point probes are provided in order to contact the upper surface of a semiconductor wafer placed on a measurement stage and measure the resistivity of the semiconductor wafer, and the probe is equipped with a plurality of four-point probes corresponding to the types of semiconductor wafers. The method is configured to operate one of the plurality of probe vertical drive units selected by the method, select an appropriate four-probe probe, and measure the resistivity of the semiconductor wafer using the selected probe. "There is."

Japanese Patent Application Publication No. 2005-311009 Japanese Patent Application Publication No. 2003-163248

However, due to differences in warpage, deflection, thickness, etc. of semiconductor wafers handled in actual manufacturing lines, in-plane measurement is difficult with the desired control information (rotation angle and load control program) stored in advance in memory as in Patent Document 1. Load errors may occur at coordinate positions.

An object of the present disclosure is to provide a technology that can solve the above problems, correct the load error that occurs for each semiconductor wafer film type and each measurement coordinate, and improve the stability and reproducibility of resistivity measurement values. .

According to one aspect of the present disclosure,
A table on which the object to be measured is placed, a probe that brings a plurality of probes into contact with the object to be measured, a horizontal drive section that moves the probe in the horizontal direction, a vertical drive section that moves the probe in the vertical direction, and a A displacement meter measures the amount of push between the probe and the object to be measured, a horizontal drive section moves the probe to the measurement position of the object to be measured, a vertical drive section brings the probe into contact with the object, and a displacement meter moves the probe to the measurement position of the object to be measured. A technique is provided that includes a control unit that actually measures the amount pushed into an object, compares the measured value with an arbitrary set value, and performs control to correct the error if the error is outside a threshold.

According to the present disclosure, it is possible to improve the stability and reproducibility of resistivity measurements.

FIG. 1 is a block diagram showing the configuration of a semiconductor wafer resistivity measuring device according to an embodiment of the present disclosure. FIG. 2 is an external view showing the configuration of a probe vertical drive unit, a four-probe probe, a semiconductor wafer, a measurement stage, and a displacement meter according to an embodiment of the present disclosure. It is a graph showing experimental values showing the relationship between the amount of pushing of the probe, the rotation angle of the vertical drive cam, and the cam stress. 3 is a flowchart showing a measurement operation according to an embodiment of the present disclosure. FIG. 3 is a diagram showing the relationship among a four-probe probe, a constant current source, a voltmeter, and a semiconductor wafer in a four-probe measurement method.

Hereinafter, one embodiment of the present disclosure will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, the semiconductor wafer resistivity measuring instrument 100 includes a measurement stage 1, an operating section 3, a four-point probe 4, a measurement section 5, a probe vertical drive section 6, a probe horizontal drive section 7, a stage rotation drive 8, a power supply section 9, a control section 10, a display section 11, and a displacement meter 12.

The measurement stage 1 has a disk-shaped upper surface, and is a table on which a semiconductor wafer 2 as a measurement target (object to be measured) is placed. The operation unit 3 outputs information specifying the position of a required measurement point on the upper surface of the semiconductor wafer 2 to the control unit 10. The four-point probe 4 is a probe having four probes 4a, 4b, 4c, and 4d that touch the top surface of the semiconductor wafer 2 placed on the measurement stage 1 to measure the resistivity of the semiconductor wafer 2. be. The measurement unit 5 is electrically connected to the four-point probe 4 in order to measure the resistivity of the semiconductor wafer 2.

The probe vertical drive unit 6 is a vertical drive unit that independently moves each of the probes 4a, 4b, 4c, and 4d of the four-probe probe 4 in the vertical direction and brings them into contact with the semiconductor wafer 2. The horizontal probe drive unit 7 is a horizontal drive unit that moves the probe vertical drive unit 6 and the four-probe probe 4 in the radial direction of the measurement stage 1, that is, in the diametrical direction of the semiconductor wafer 2. The stage rotation drive unit 8 rotates the measurement stage 1 and stops it at a predetermined angle. The operation of both the probe horizontal drive section 7 and the stage rotation drive section 8 enables resistivity measurement at a desired position on the semiconductor wafer 2.

The power supply unit 9 supplies power to operate each part of the resistivity measuring device 100. The control unit 10 includes a CPU and a memory that stores a control program executed by the CPU, and drives and controls the stage rotation drive unit 8, the probe horizontal drive unit 7, and the probe vertical drive unit 6 according to control information commanded from the operation unit 3. Then, the four-point probe 4 is controlled so as to come into contact with the designated measurement point position on the upper surface of the semiconductor wafer 2. The display unit 11 displays data such as the measurement point position and the resistivity of the measured results.

The displacement meter 12 is provided near the 4-point probe 4, and the vertical position of the 4-point probe 4 is controlled by the probe vertical drive section 6 according to control information (indentation amount) arbitrarily set from the control section 10. At this time, the actual amount of displacement between the top surface of the semiconductor wafer 2 and the four-point probe 4 is measured, and the actual amount of displacement is fed back to the control unit 10 to check whether it matches arbitrarily set control information (indentation amount). If there is an error, it is corrected so that they match.

In FIG. 1, the operation is such that a four-point probe 4, which is controlled based on control information input from an operation unit 3, contacts the top surface of a semiconductor wafer 2 placed on a measurement stage 1, and the semiconductor wafer 2 is placed on a measurement stage 1. A resistance measurement is made.

Next, the probe vertical drive section 6 will be explained using FIG. 2. The probe vertical drive unit 6 includes a probe mounting bracket 6a, a cam receiver 6h, a weight 6e, a vertical drive cam 6f, and a stepping motor 6g.

A four-probe probe 4 is attached to the probe attachment fitting 6a. The cam receiver 6h receives a probe vertical driving force integrated with the probe mounting bracket 6a. The weight 6e has sufficient mass to apply a vertical static load to the probe vertical drive unit 6. The vertical drive cam 6f is connected to the shaft of the stepping motor 6g, and by always keeping in contact with the tip of the cam receiver 6h, the weight of the probe mounting bracket 6a, including the weight of the weight 6e, is transferred to the stepping motor 6g. Support on the axis. The vertical drive cam 6f has, for example, an eccentric circular cam shape, and can move the cam receiver 6h vertically depending on the rotation angle. The stepping motor 6g has a cam receiver 6h supported by a probe mounting bracket 6a and a vertical drive cam 6f supported by a support member independent of the probe mounting bracket 6a, which are coupled together by a shaft, and are commanded by the control unit 10. It can rotate and stop at any rotation angle according to control information.

With the above configuration, the probe vertical drive unit 6 is controlled according to the control information having the load to be applied to the probe and the probe vertical movement speed appropriate for the type of semiconductor wafer 2, and appropriate contact between the four-probe probe 4 and the semiconductor wafer 2 is achieved. The resistivity of the semiconductor wafer 2 is measured by realizing this.

Here, FIG. 3 shows experimental values showing the relationship between the pushing amount of the probes 4a to 4d, the rotation angle of the vertical drive cam 6f, and the spring stress acting as a load on the semiconductor wafer 2. Furthermore, the relationship between the pushing amount, the rotation angle of the vertical drive cam 6f, and the load as shown in the graph of FIG. 3 is stored in advance in the storage device of the control unit 10 as a control program. In this way, the control unit 10 adjusts the rotation angle of the vertical drive cam 6f and stops the four-probe probe 4 at an arbitrary position (pushing amount) shown in FIG. 3, so that the probes 4a to 4d are The load to be applied to the semiconductor wafer 2 can be set, and the contact pressure can be arbitrarily controlled to match the surface material of the semiconductor wafer 2.

Next, a method for measuring resistivity of a semiconductor wafer using the resistivity measuring device 100 will be described using FIG. 4.

(Step S1)
The control unit 10 causes a probe horizontal drive unit 7 to move the probe vertical drive unit 6 and the four-probe probe 4 in the diametrical direction, and a stage rotation drive unit 8 to rotate the measurement stage 1 on which the semiconductor wafer 2 is placed. and move the four-point probe 4 to a desired position on the semiconductor wafer 2.

(Step S2)
The control unit 10 lowers the four-probe probe 4 by setting an arbitrary push-in amount using the probe vertical drive unit 6 to bring the probes 4a to 4d into contact with the semiconductor wafer 2.

(Step S3)
As shown in FIG. 5, the contact reference position (the position at which the pushing amount is 0.00 mm) is determined by the control unit 10 measuring the voltage between the probes 4b and 4c of the four-probe probe 4 using a voltmeter 14. to determine whether the voltage is within 0 mV±threshold value.

(Step S4)
The control unit 10 sets the timing when the voltage between the probe 4b and the probe 4c becomes 0 mV in step S3 as a contact reference position (position where the pushing amount is 0.00 mm).

(Step S5)
The control unit 10 causes the four-point probe 4 to rise using the probe vertical drive unit 6.

(Step S6)
The control unit 10 lowers the four-probe probe 4 by setting an arbitrary push-in amount using the probe vertical drive unit 6 to bring it into contact with the semiconductor wafer 2 .

(Step S7)
The control unit 10 determines whether the error between the arbitrary push amount set value and the actual push amount (displacement amount) measured by the displacement meter 12 is within a threshold value.

(Step S8)
If the error between the arbitrary push amount set value and the actual push amount (displacement measurement) measured by the displacement meter 12 is not within the threshold value, the control unit 10 corrects the error and moves to step S5 to re-execute. Note that even if the four-probe probe 4 is re-executed a predetermined number of times, the control unit 10 stops the resistivity measurement if the voltage value between the probe 4b and the probe 4c is outside the threshold value. . In this case, the control section 10 displays an alarm on the display section 11 indicating the stop of resistivity measurement.

(Step S9)
If the error is within the threshold, the control unit 10 measures the resistivity.

According to this embodiment, the operation is performed according to the control information (indentation amount) arbitrarily set by the control unit 10, when the four-point probe 4 is vertically controlled by the probe vertical drive unit 6, the displacement is Total 12 measures the actual displacement between the top surface of the semiconductor wafer 2 and the four-point probe 4, feeds back the actual displacement to the control unit 10, and checks whether it matches arbitrarily set control information (indentation amount). If there is an error, it is automatically corrected to match.

With the above configuration, the probe vertical drive unit 6 is controlled according to the control information having the load to be applied to the probe and the probe vertical movement speed appropriate for the type of semiconductor wafer 2, and appropriate contact between the four-probe probe 4 and the semiconductor wafer 2 is achieved. It is possible to realize this and measure the resistivity of the semiconductor wafer 2.

In this embodiment, the resistivity of a silicon wafer, the resistivity of an epitaxial wafer formed on the wafer surface, the sheet resistance of a diffusion layer or an injection layer when impurities are diffused or implanted from the surface, the sheet resistance of a metal film formed on the surface, etc. The resistivity of semiconductor wafers is measured using a resistivity measuring instrument, and the measurement results are fed back to the process conditions of each semiconductor manufacturing equipment.In other words, the process conditions are set in the semiconductor manufacturing equipment based on the measurement results, and the semiconductor manufacturing equipment By processing semiconductor wafers, it becomes possible to improve the uniformity of the quality of semiconductor devices.

<Preferred embodiments of the present disclosure>
Preferred embodiments of the present disclosure will be additionally described below.

(Additional note 1)
According to one aspect of the present disclosure,
A table on which the object to be measured is placed;
a probe that brings a plurality of probes into contact with the object to be measured;
a horizontal drive unit that moves the probe horizontally;
a vertical drive unit that moves the probe in the vertical direction;
a displacement meter that measures the amount of push between the object to be measured and the probe;
The probe is moved to a measurement position of the object to be measured by the horizontal drive section, the probe is brought into contact with the object to be measured by the vertical drive section, and the amount by which the probe is pushed into the object to be measured by the displacement meter. a control unit that measures the actual value, compares the measured value with an arbitrary set value, and controls the error to be corrected if the error is outside the threshold;
A resistivity measuring instrument is provided.

(Additional note 2)
According to other aspects of the disclosure:
A table on which an object to be measured is placed, a probe that brings a plurality of probes into contact with the object to be measured, a horizontal drive section that moves the probe horizontally, and a vertical drive section that moves the probe up and down. a displacement meter that measures the amount of pushing of the probe into the object to be measured; the horizontal drive section moves the probe to the measurement position of the object to be measured; and the vertical drive section moves the probe to the object to be measured. The probe is brought into contact with the object to be measured, and the displacement meter actually measures the amount by which the probe is pushed into the object to be measured, and this measured value is compared with an arbitrary set value, and if the error is outside the threshold, the error is corrected. A resistivity measuring device comprising a control unit for controlling the resistivity of the silicon wafer, the resistivity of the epitaxial wafer formed on the wafer surface, and the sheet resistance or surface of the diffusion layer or injection layer when impurities are diffused or implanted from the surface. a step of measuring the sheet resistance of the metal film produced;
setting process conditions for a semiconductor manufacturing device based on the measured resistivity or sheet resistance;
processing a semiconductor wafer based on set process conditions;
A method for manufacturing a semiconductor device comprising:

(Additional note 3)
In the resistivity measuring device according to Supplementary Note 1, preferably,
The control unit determines whether the measurement position is a reference according to a voltage value between a first probe of the plurality of probes and a second probe of the other one of the plurality of probes. It is configured to determine whether the location is

(Additional note 4)
In the resistivity measuring device according to appendix 3, preferably,
The control unit is configured to set the measurement position to a reference position if a voltage value between the first probe and the second probe is within a threshold value.

(Appendix 5)
In the resistivity measuring device according to appendix 3, preferably,
The control unit is configured to re-execute the lowering of the probe if the voltage value between the first probe and the second probe is outside a threshold value.

(Appendix 6)
In the resistivity measuring device according to appendix 4, preferably,
The control unit is configured to stop resistivity measurement if the voltage value between the probes is outside a threshold even if the probe is re-executed a predetermined number of times. There is.

(Appendix 7)
In the resistivity measuring device according to Supplementary Note 1, preferably,
The control section is configured to raise and lower the vertical drive section to adjust the amount of pushing.

(Appendix 8)
In the resistivity measuring device according to appendix 7, preferably,
The vertical drive section includes at least a probe mounting section having a predetermined weight, a motor section (stepping motor), a vertical drive cam section, and a cam receiving section.

(Appendix 9)
In the resistivity measuring device according to appendix 8, preferably,
The control section is configured to adjust the rotation angle of the vertical drive cam section.

(Appendix 10)
In the resistivity measuring device according to Supplementary Note 1, preferably,
Furthermore, it has a display section,
The control section is configured to display an alarm on the display section indicating the stop of resistivity measurement.

1...Measurement stage (stand)
2...Semiconductor wafer (object to be measured)
4...4-point probe (probe)
4a to 4d... Probe 6... Probe vertical drive section (vertical drive section)
7... Probe horizontal drive section (horizontal drive section)
10...Control unit 12...Displacement meter 100...Resistivity measuring device

Claims (12)

A table on which the object to be measured is placed;
a probe that brings a plurality of probes into contact with the object to be measured;
a horizontal drive unit that moves the probe horizontally;
a vertical drive unit that moves the probe in the vertical direction;
a displacement meter that measures the amount of push between the object to be measured and the probe;
The horizontal drive section moves the probe to the measurement position of the object to be measured, the vertical drive section brings the probe into contact with the object to be measured, and the amount by which the probe is pushed into the object by the displacement meter. a control unit that measures the actual value, compares the measured value with an arbitrary set value, and controls the error to be corrected if the error is outside the threshold;
Equipped with
The control unit brings the probe into contact with the object to be measured, and controls between a first probe of one of the plurality of probes and a second probe of another one of the plurality of probes. A resistivity measuring instrument configured to determine a reference position according to a voltage value of . The control unit is configured to set a contact position of the probe with the object to be measured as a reference position if a voltage value between the first probe and the second probe is within a threshold value. The resistivity measuring device according to claim 1 . The resistivity measurement according to claim 1 , wherein the control unit is configured to re-execute the lowering of the probe if the voltage value between the first probe and the second probe is outside a threshold value. vessel. The control unit is configured to stop resistivity measurement if the voltage value between the probes is outside a threshold even if the probe is re-executed a predetermined number of times. 4. The resistivity measuring device according to claim 3 . 2. The resistivity measuring instrument according to claim 1, wherein the control section is configured to adjust the pushing amount by raising and lowering the vertical drive section. 2. The resistivity measuring instrument according to claim 1, wherein the vertical drive section includes at least a probe mounting section having a predetermined weight, a motor section, a vertical drive cam section, and a cam receiving section. 7. The resistivity measuring instrument according to claim 6 , wherein the control section is configured to adjust the rotation angle of the vertical drive cam section. Furthermore, it includes a display section,
7. The resistivity measuring instrument according to claim 6 , wherein the control section is configured to adjust the rotation angle of the vertical drive cam section. 2. The resistivity measuring instrument according to claim 1, wherein the object to be measured is a wafer including a silicon wafer. The control unit controls the resistivity of the silicon wafer, the resistivity of the epitaxial wafer formed on the wafer surface, the sheet resistance of a diffusion layer or injection layer when impurities are diffused or implanted from the surface, or the sheet resistance of a metal film formed on the surface. The resistivity measuring device according to claim 1, wherein the resistivity measuring device is configured to be able to measure at least one of the following. A table on which an object to be measured is placed, a probe that brings a plurality of probes into contact with the object to be measured, a horizontal drive section that moves the probe horizontally, and a vertical drive section that moves the probe up and down. a displacement meter that measures the amount of pushing of the probe into the object to be measured; the horizontal drive section moves the probe to the measurement position of the object to be measured; and the vertical drive section moves the probe to the object to be measured. The probe is brought into contact with the object to be measured, and the displacement meter actually measures the amount by which the probe is pushed into the object to be measured, and this measured value is compared with an arbitrary set value, and if the error is outside the threshold, the error is corrected. A control unit for controlling the
The control unit brings the probe into contact with the object to be measured, and controls between a first probe of one of the plurality of probes and a second probe of another one of the plurality of probes. measuring the resistivity or sheet resistance of the object to be measured using a resistivity measuring device configured to determine a reference position according to a voltage value ;
setting process conditions for a semiconductor manufacturing device based on the measured resistivity or sheet resistance;
processing a semiconductor wafer based on set process conditions;
A method for manufacturing a semiconductor device comprising: A table on which an object to be measured is placed, a probe that brings a plurality of probes into contact with the object to be measured, a horizontal drive section that moves the probe horizontally, and a vertical drive section that moves the probe up and down. a displacement meter that measures the amount of pushing of the probe into the object to be measured; the horizontal drive section moves the probe to the measurement position of the object to be measured; and the vertical drive section moves the probe to the object to be measured. The probe is brought into contact with the object to be measured, and the displacement meter actually measures the amount by which the probe is pushed into the object to be measured, and this measured value is compared with an arbitrary set value, and if the error is outside the threshold, the error is corrected. A control unit for controlling the
The control unit brings the probe into contact with the object to be measured, and controls between a first probe of one of the plurality of probes and a second probe of another one of the plurality of probes. A resistivity measuring method comprising the step of measuring the resistivity or sheet resistance of the object to be measured using a resistivity measuring device configured to determine a reference position according to a voltage value of the object.

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