Probe device and probe method

1. A probe device for inspecting electrical characteristics of an object W to be inspected, comprising:

a mounting table for mounting thereon the object to be inspected, the mounting table being movable in X, Y, Z and θ directions;

a probe card disposed above the mounting table and provided with a plurality of probes; and

a contact load monitoring device including at least one displacement sensor and a control device and monitoring a contact load exerted on the mounting table by the probes during an overdriving stage,

wherein the displacement sensor is disposed in a space below the mounting table and measures, as an amount of sinking, a displacement of a reference surface at a bottom side of the mounting table caused by the contact load exerted on the mounting table by the probes during the overdriving stage;

wherein the control device is provided with a correlation table for amounts of sinking of the reference surface of the mounting table and contact loads and estimates a contact load by using the displacement measured by the displacement sensor and the correlation table; and

wherein the control device adjusts the contact load to be identical with a designed contact load by further elevating the mounting table in case the contact load is less than the designed contact load.

2. The probe device of claim 1 , wherein the displacement sensor is one of an analog and a digital output displacement sensor.

3. The probe device of claim 1 , wherein the displacement sensor is one of a capacitive displacement sensor and an eddy current displacement sensor.

4. The probe device of claim 1 , wherein the displacement sensor is disposed on at least one of a center of the mounting table and a plural locations therearound.

5. A method for inspecting electrical characteristics of an object to be inspected by using the probe device of claim 1 , comprising the steps of:

(a) setting a designed overdriving amount and a designed contact load corresponding to the object W to be inspected in the control device;

(b) bringing the object to be inspected into contact with the probes by elevating the mounting table on which the object to be inspected is mounted;

(c) overdriving the mounting table based on the designed overdriving amount;

(d) monitoring whether the contact load exerted on the mounting table is identical with the designed contact load by using the contact load monitoring device, wherein the monitoring step (d) includes the steps of:

(d1) measuring the displacement of the reference surface at a bottom side of a support member as the amount of sinking of the mounting table and outputting the measured displacement to the control device by the displacement sensor disposed in a space below the mounting table;

(d2) estimating the contact load corresponding to the displacement based on the correlation table and comparing the estimated contact load with the designed contact load by the control device;

(d3) further elevating the main chuck in case the contact load estimated based on the displacement measured by the displacement sensor is less than the designed contact load; and

(d4) repeating the steps (d1) through (d3) and stopping the elevation of the main chuck when the contact load based on the displacement measured by the displacement sensor reaches the designed contact load; and

(e) inspecting the electrical characteristics of the object W to be inspected.

6. A probe device for inspecting electrical characteristics of an object to be inspected, said probe device comprising:

a movable mounting table configured to mount thereon the object to be inspected;

a probe card disposed above said movable mounting table and provided with a plurality of probes; and

a contact load monitoring device including a displacement sensor and a control device, said contact load monitoring device being configured to monitor a contact load exerted on said mounting table by said plurality of probes during an overdriving stage,

wherein said displacement sensor is disposed underneath said mounting table, said displacement sensor being configured to measure a displacement of a reference surface at a bottom side of said mounting table during the overdriving stage,

wherein said control device is provided with a correlation table for estimating the contact load based on the displacement of said reference surface, and

wherein said control device is configured to adjust the contact load to be equal to a designed contact load by moving said mounting table to achieve a displacement of said reference surface that correlates to the designed contact load based on the correlation table.

7. The probe device of claim 6 , wherein said displacement sensor is one of an analog displacement sensor and a digital output displacement sensor.

8. The probe device of claim 6 , wherein said displacement sensor is one of a capacitive displacement sensor and an eddy current displacement sensor.

9. The probe device of claim 6 , wherein said displacement sensor is disposed on at least one of a center of said mounting table and plural locations therearound.

10. A method for inspecting electrical characteristics of an object to be inspected using a probe device including a movable mounting table, a probe card provided with a plurality of probes, and a contact load monitoring device including a displacement sensor and a control device, said method comprising the steps of:

(a) setting a designed overdriving amount and a designed contact load corresponding to the object to be inspected in the control device;

(b) bringing the object to be inspected into contact with the probes by elevating the mounting table on which the object to be inspected is mounted;

(c) overdriving the mounting table based on the designed overdriving amount;

(d) monitoring whether the contact load exerted on the mounting table is identical with the designed contact load by using the contact load monitoring device, wherein the monitoring step (d) includes the steps of:

(d1) measuring a displacement of a reference surface at a bottom side of the mounting table as an amount of sinking and outputting the measured displacement to the control device, using the displacement sensor disposed underneath the mounting table;

(d2) estimating the contact load corresponding to the displacement based on a correlation table in the control device and comparing the estimated contact load with the designed contact load;

(d3) further elevating the main chuck in case the contact load estimated based on the displacement measured by the displacement sensor is less than the designed contact load; and

(d4) repeating the steps (d1) through (d3) and stopping the elevation of the main chuck when the contact load based on the displacement measured by the displacement sensor reaches the designed contact load; and

(e) inspecting the electrical characteristics of the object to be inspected.