JPH05264590A - Warp correction mechanism for probe card - Google Patents

Abstract

PURPOSE:To obtain a mechanism for correcting a warp generated on a probe card due to the rise of inspection temperature during the inspection of an LSI tip using the probe card. CONSTITUTION:On the probe card 3 surface, warp detection piezoelectric elements 61, 63 and warp correction piezoelectric elements 62, 64 are contacted in parallel. A correction voltage generation circuit 7 is provided to input the detection voltage detected by the warp detection piezoelectric elements and supply the bend correction piezoelectric elements with a generated correction voltage with reverse phase to the detection voltage. Thus, the warp of the probe card is corrected and the probe of the probe pin surely contacts the pad terminals corresponding to the LSI tips, and so reliable LSI tip inspection becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for correcting a warp generated in a probe card for inspecting an LSI formed on a wafer.

[0002]

2. Description of the Related Art In FIG. 3A, a large number of LSI chips 2 are formed on the surface of a wafer 1, and an electronic circuit pattern 2b of each LSI chip 2 is connected to a pad terminal 2a for external wiring. Each LSI chip is divided one by one,
An LSI device is manufactured by connecting the pad terminal 2a to the lead frame. Before the LSI chip 2 is divided,
The characteristics are inspected by the probe card when it is formed on the wafer. FIG. 3 (b) shows an example of a probe card used for inspection. The probe card 3 has an opening 3a at the center of a circular substrate 3 and a pad terminal 2a around the opening 3a.
Is formed by arranging probe pins 3b corresponding to. Each probe pin 3b has elasticity, and a probe 3c is implanted at its tip. FIG. 3C shows an inspection method of the LSI chip 2. The wafer 1 is placed on the inspection stage 4, and the outer periphery of the probe card 3 is fixed to the lower surface of the test head 5. First, the wafer 1 is heated to a high temperature (for example + 60 ° C.) or cooled to a low temperature (for example −50 ° C.). Then, the inspection stage 4 is moved by an XYZ moving mechanism (not shown).
Is moved in the X or Y direction to stop the predetermined LSI chip 2 at the position of the opening 3a, and further raised Z to bring each pad terminal 2a into contact with the corresponding probe 3c for inspection.

[0003]

In the above inspection,
When the wafer 1 is maintained at a high temperature or a low temperature, the temperature of the wafer 1 influences the probe card 3 to a high temperature or a low temperature, causing stress. However, since the outer periphery of the probe card 3 is fixed to the test head 5, stress is only inherent at low temperatures, but at high temperatures, the probe card itself expands and warps occur around the openings 3a. ,
This may cause poor contact between the pad terminal 2a and the probe 3c. FIG. 4 shows a state in which the probe card 3 is warped. The solid line shows the case where the probe card 3 is warped downward, and the probe (a) at the center is in contact with the pad terminal 2a. The outer probes (b) and (c) ascend by the amount of warp and incline outward and do not contact the corresponding pad terminals 2a. On the other hand, as indicated by the dotted line, when the probe card 3 is warped upward, the probes (b) and (c) may incline inward and come into contact with the adjacent pad terminals 2a. B) does not touch because it rises. The poor contact caused by the warp is absorbed to some extent by the elasticity of the probe pin 3b. However, recently, in a VLSI having a higher degree of integration, since the number of pad terminals 2a has increased, a probe card having a diameter larger than that of the conventional one, for example, 200 to 250 mm is used. With such a diameter, the generated warp is several tens of μmm.
Reach On the other hand, the allowable limit of the warp is set to 10 μmm or less, and the warp cannot be absorbed due to the elasticity of the probe pin. The present invention has been made in view of the above, and it is an object of the present invention to provide a mechanism for correcting a warp generated in the probe card 3 due to an increase in inspection temperature.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a warp correction mechanism for a probe card, which includes a warp detection piezoelectric element for detecting a warp generated on the surface of the probe card due to a rise in inspection temperature. A warp correction piezoelectric element that applies a force in the opposite direction to the warp and corrects the warp is bonded in parallel. Further, a correction voltage generating circuit is provided which receives a detection voltage detected by the warp detection piezoelectric element, generates a correction voltage having a phase opposite to the detection voltage and supplies the correction voltage to the warp correction piezoelectric element.

[0005]

In general, a piezoelectric element is distorted (warped) by an applied external force, and a voltage corresponding to this is generated. On the contrary, when a voltage is applied, warpage occurs. Considering the voltage as a reference, the direction of the warp that generates the voltage and the direction of the warp due to the applied voltage are the same. Therefore, with respect to the voltage generated by the warp, the warp should be able to be corrected by giving a voltage that causes the opposite warp, that is, a voltage having an opposite phase. According to this principle, in the above-mentioned warp correction mechanism, the warp detection piezoelectric element detects the warp of the probe card caused by the rise of the inspection temperature, and outputs the detected voltage according to the warp. The detection voltage is input to the correction voltage generation circuit, a correction voltage having a phase opposite to the detection voltage is generated and supplied to the warp correction piezoelectric element, and a force in the opposite direction is applied to the warp of the probe card. Since both piezoelectric elements are arranged in parallel on the surface of the probe card, the same amount of action is applied to the probe card and the warp is corrected to zero or near this, and the probe pin of each probe pin corresponds. Good contact with pad terminals.

[0006]

1 shows an embodiment of the present invention. The wafer 1 to be inspected is placed on the inspection stage 4, and the XYZ (not shown)
The moving mechanism moves in the X or Y direction and moves up and down in the Z direction. Above the wafer 1, a head 5a and a fixing ring 5b are provided.
The test head 5 is provided, and the mounting bolt 5c is used to fix the periphery of the probe card 3 to the fixing ring 5b. The warp detection piezoelectric elements (A) 61 and (B) 63 and the warp correction piezoelectric elements (A) 62 and (B) 64 are symmetrically arranged on both sides of the opening 3a of the probe card 3 to prevent warpage. Each piezoelectric element is bonded to the surface of the probe card 3 so that the above can be detected or corrected reliably. Each piezoelectric element is connected to the correction voltage generation circuit 7. The reason why the piezoelectric elements are symmetrically arranged on both sides of the opening 3a is that the warp is not always balanced on both sides, so that the warp is surely corrected. FIG. 2 shows a schematic configuration of the correction voltage generating circuit 7, which includes phase inverters 71 and 73 for inverting the phases of the detection voltages of the warp detection piezoelectric elements (A) 61 and (B) 63, and the respective output voltages. The amplifiers 72 and 74 are adjusted to various levels, and the output of each amplifier is supplied as a correction voltage to the warp correction piezoelectric elements (A) 62 and (B) 64, respectively.

A warp correction of the probe card 3 and a method of inspecting the LSI chip 2 will be described with reference to FIGS. 1 and 2. XY
The wafer 1 is moved in the X or Y direction by the Z moving mechanism,
The target LSI chip 2 is stopped at the position of the opening 3a, and then Z-lifted to bring each pad terminal 2a into contact with the corresponding probe 3c. The warp generated in the probe card 3 due to the effect of heating the wafer 1 is detected by the warp detection piezoelectric elements (A) 61 and (B) 63, respectively. Each detection voltage is input to the correction voltage generation circuit 7, a correction voltage of an appropriate level is output in a phase opposite to the detection voltage, and the correction voltages are input to the warp correction piezoelectric elements (A) 62 and (B) 64, respectively, and the warp is zero. Or it will be corrected near this. By this correction, each probe 3
The pad terminal 2a corresponding to c is surely brought into contact with the pad terminal 2a, and the LSI chip 2 is inspected with reliability.

[0008]

As described above, in the warp correction mechanism of the probe card according to the present invention, the warp generated in the probe card due to the rise in the inspection temperature is detected by the warp detection piezoelectric element and detected by the correction voltage generation circuit. Generates a correction voltage in the opposite phase to the voltage and supplies it to the warpage correction piezoelectric element to correct the warpage of the probe card and ensure that the probe pin of each probe pin contacts the corresponding pad terminal of the LSI chip. There is a big part that contributes to a proper LSI chip inspection.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows a schematic configuration of a correction voltage generation circuit in FIG.

3A is an explanatory diagram of an LSI chip formed on a wafer, FIG. 3B is a diagram showing an example of a probe card for LSI inspection, and FIG. 3C is an explanatory diagram of an LSI chip inspection method by the probe card. is there.

FIG. 4 is an explanatory diagram of contact failure due to warpage of the probe card.

[Explanation of symbols]

1 ... Wafer, 2 ... LSI chip, 2a ... Pad terminal, 2
b ... Electronic circuit pattern, 3 ... probe card, 3a ... opening, 3b ... probe pin, 3c ... probe, 4 ... inspection stage, 5 ... test head, 5a ... head, 5b ... fixing ring, 5c ... mounting bolt 61 Warp detection piezoelectric element (A), 63 ... Warp detection piezoelectric element (B), 62 ... Warp correction piezoelectric element (A), 64 ... Warp correction piezoelectric element (B), 7 ... Correction voltage generating circuit, 71, 73 ... Phase inverter, 72,74… Amplifier.

Claims (1)

[Claims] 1. In the inspection of an LSI chip, which is performed by bringing a probe pin of a probe card into contact with a pad terminal of an LSI chip formed on a wafer, an increase in inspection temperature with respect to the surface of the probe card. A warp detection piezoelectric element that detects a warp that occurs in the probe card and a warp correction piezoelectric element that corrects by applying a force in the opposite direction to the warp are bonded in parallel, and the warp detection piezoelectric element is detected. A warp correction mechanism for a probe card, comprising a correction voltage generation circuit that receives a voltage, generates a correction voltage having a phase opposite to the detection voltage, and supplies the correction voltage to the warp correction piezoelectric element.