JPH0336746A - Wafer probe - Google Patents

Abstract

PURPOSE:To prevent the time for deciding whether or not the shape and position of a probe needle is satisfactory from overlapping with the time for measuring and testing a semiconductor device by providing a mechanism for recognizing the shape and position of the probe needle and conducting a composition and judgement with a normal shape and position. CONSTITUTION:The shape and position of a normal state probe needle 12 are stored using a camera 1 and an image processing circuit 8. For decision of whether or not the probe needle 123 is satisfactory, the shape and position of the probe needle 12 are again incorporated at that time and compared with image data at the normal state of the same. The result is fed to a body control circuit through a control circuit 9. For timing for performing a needle check, the incorporation of the normal state is done at a time when a probe card 4 is exchanged or before the measurement and testing of the semiconductor device, and for decision of whether or not the probe needle is satisfactory, it can be done at arbitrary timing in the measurement and test of the semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a wafer prober for measuring and testing the electrical characteristics and functions of semiconductor devices formed on a wafer.

[Prior Art] Conventionally, there has been no prober equipped with a needle check mechanism. Instead, the reliability of the measurements and tests was guaranteed by checking the course on the pad using image processing technology after the measurements and tests.

[Problem to be solved by the invention] However, with conventional technology.

(1) Since it is impossible to judge whether the probe is good or bad without actually making a needle mark, if the probe needle is already deformed, there is a risk of fatal scratches on the wafer.

(2) The first check before measurement or testing or after wafer exchange uses a predetermined semiconductor device for checking, which wastes time.

There was a problem.

In order to solve these conventional problems, the present invention has the following objectives: (1) Before bringing the probe needle into contact with the wafer, it is determined whether the shape and position of the probe needle are good or bad.

(2) The time for (1) should not be added to the time for measuring and testing semiconductor devices.

The purpose is to

[Means for Solving the Problems] The wafer prober of the present invention includes: (1) a mechanism that recognizes the shape and position of the probe needle and compares and judges the shape and position with the normal shape and position (hereinafter referred to as "needle checking mechanism"); has been established.

(2) The needle check mechanism is equipped with an image capturing camera, lighting, and an image processing circuit.

(3) A plurality of the image capturing cameras were provided at different positions.

(4) The image capturing camera is provided at two locations, one vertically downward and the other horizontally relative to the probe needle attachment position.

[Function] Since the present invention has the above-described mechanism, the needle check mechanism eliminates the need to test needle marks, eliminates wasted time for measuring and testing semiconductor devices, and prevents deformation. This prevents the wafer from being scratched by the probe needle.

[Example] Figure 1 is a cross-sectional view of the wafer prober of the present invention, and Figure 2 is a cross-sectional view of the wafer prober of the present invention.
The figure is a cross-sectional view of the wafer prober of the present invention, and FIG. 3 is a block diagram of the control system of the wafer prober of the present invention. Examples will be described below with reference to the drawings. The control circuit 9 is connected to the main body control circuit 11 and controls the needle check operation. As a needle check method, (1) The shape and position of the probe needle 12 in a normal state are memorized by the camera l and the image processing circuit 8. At that time, the lighting 2 is turned on so that the image can be captured clearly.

(2) To judge whether the probe needle 12 is good or bad, at that point, the shape and position of the probe needle 12 are taken in again in the same manner as in (1), and compared with normal image data to judge whether the probe needle is good or bad.

(3) The result of (2) is transmitted to the main body control circuit through the control circuit 9.

The timing of the needle check is to capture the normal state when the probe card 4 is replaced or before the measurement or test of the semiconductor device, and to determine the pass/fail condition at any time during the measurement or test of the semiconductor device. The main body control circuit 11 controls the control circuit 9 to enable one or more timings. Then, depending on the pass/fail result from the control circuit 9, processing such as stopping the measurement or test or generating an alarm is performed.

Next, the mounting position of the camera 1 will be described. Cases where an abnormality in the shape of the probe needle 12 becomes a problem include (1) when the positional relationship between the test pad of the semiconductor device and the probe needle 12 is out of order;

(2) When the probe needle 12 is deformed in the height direction.

There are two ways to do this, and in either case, the semiconductor device may be damaged or electrical contact may not be established, making it impossible to perform accurate measurements or tests.Therefore, in this embodiment, camera 1 is As shown in the figure and FIG. 2, the probe needle 12 is attached vertically downward and horizontally so that the position and height can be checked. In this case, during the measurement and testing of the semiconductor device, the stage 6 is moved below the probe card 3, so it blocks the camera 1-a, making it impossible to capture the shape and position of the probe needle 12. Regarding this point, the problem can be solved by moving the stage 6 to the position shown in FIGS. 1 and 2 (a position that does not block the field of view of the camera l) by the main body control circuit 11 at the timing of the needle check. In addition, in actual operation, if the timing of the needle check is as shown below, the time loss due to the above stage movement can be kept to a minimum.

(1) This is performed when the stage 6 moves to the loader/unloader 7 side during wafer exchange.

(2) Perform every certain number of semiconductor devices during measurement and testing.

(3) Instead of (2), perform this only if a certain number of defects occur in succession.

[Effect of the invention 1 As described above, according to the present invention, the needle check mechanism lO
By providing this, the shape and position of the probe needle 12 can be determined in advance without contacting the semiconductor device with the probe needle 12, thereby (1) reducing the risk of damaging the wafer; and (2) reducing the risk of damaging the semiconductor device. It has a great effect on improving the reliability of measurements and tests.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the wafer prober of the present invention. FIG. 2 is a longitudinal sectional view of the wafer prober of the present invention. FIG. 3 is a block diagram of the control system of the wafer prober of the present invention.・Camera・P3 light・Interface with test system・Probe card・Stage drive shaft・Stage・Rogue/unloader・Image processing circuit・Control circuit・Needle check mechanism・Main body control circuit

Claims (4)

[Claims] (1) In a wafer prober that measures and evaluates the electrical characteristics and functions of a semiconductor device by bringing the probe needle into contact with a test pad of a semiconductor device formed on a wafer, the shape and position of the probe needle are recognized. A wafer prober characterized in that it is provided with a mechanism (hereinafter referred to as a "needle checking mechanism") for comparing and determining the shape and position of the wafer with a normal shape and position. (2) The wafer prober according to claim 1, wherein the needle check mechanism includes an image capturing camera, illumination, and an image processing circuit. (3) The wafer prober according to claim 2, wherein a plurality of said image capturing cameras are provided at different positions. (4) The wafer prober according to claim 3, wherein the image capturing camera is provided at two locations, one vertically downward and the other horizontally relative to the attachment position of the probe needle.