JP2802849B2 - Probe card warpage correction mechanism - Google Patents

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 testing 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 electronic circuit patterns 2b of each LSI chip 2 are connected to pad terminals 2a for external wiring. Each LSI chip is divided one by one,
The LSI device is manufactured by connecting the pad terminals 2a to the lead frame. Before the LSI chip 2 is divided,
The characteristics are inspected by the probe card at the stage of being 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 pad terminals 2a around the opening 3a.
Are arranged 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 a method of inspecting 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 rises in 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 probe card 3 becomes high or low temperature under the influence of the temperature, and stress occurs. However, since the outer periphery of the probe card 3 is fixed to the test head 5, only a stress is present at a low temperature, but at a high temperature, the probe card itself expands and warps around the opening 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 indicates a case where the probe card 3 is warped downward, and the probe (a) at the center is in contact with the pad terminal 2a, but is at a higher position than the center. The outer probes (b) and (c) rise by the amount of the warp and incline outward, and do not contact the corresponding pad terminals 2a. On the other hand, when the probe card 3 warps upward as shown by the dotted line, the probes (b) and (c) may be inclined inward and come into contact with the adjacent pad terminal 2a. B) does not touch to rise. The poor contact caused by the warpage is absorbed to some extent by the elasticity of the probe pin 3b. However, recently, in the VLSI with further improved integration, the number of pad terminals 2a has been increased, so that a probe card having a larger diameter, for example, 200 to 250 mm as compared with the conventional one is used. With such a diameter, the generated warpage is several tens of μm.
Reach On the other hand, the allowable limit of the warp is set to 10 μmm or less, and the warp cannot be absorbed by the elasticity of the probe pin. The present invention has been made in view of the above, and an object of the present invention is to provide a mechanism for correcting a warp generated in a probe card 3 due to an increase in an inspection temperature.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a warp correcting mechanism for a probe card, comprising a warp detecting piezoelectric element disposed on the surface of the probe card for detecting a warp generated in the probe card due to an increase in inspection temperature. , This warp detection
Before being installed on the surface of the probe card in parallel with the piezoelectric element
And the warp correction piezoelectric element for correcting giving backward force against warping of serial surface, the detection voltage anti Ri detecting piezoelectric element detects
Bei There is input, a correction voltage generation circuit for supplying a correction voltage of the detection voltage and the opposite phase generated in the warp correction piezoelectric element
It is something.

[0005]

In general, a piezoelectric element generates a distortion (warp) due to an applied external force, and generates a voltage corresponding thereto. That may arise from the warp and pressurize the voltage to the opposite. The voltage generated by the warp I O, voltage generated a warp of the opposite, that is, should be able to correct the warp by applying a voltage of opposite phase. According to this principle, in the above-described warp correcting mechanism, the warp detecting piezoelectric element detects the warp of the probe card caused by the rise of the inspection temperature, and outputs a detection voltage corresponding to the warp. The detected voltage is input to a correction voltage generation circuit, and a correction voltage having a phase opposite to that of the detection voltage is generated and supplied to the warp correction piezoelectric element, so that a force in a reverse 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, they act on the probe card in an equal amount and the warpage is corrected to zero or near this, and the probe of each probe pin corresponds to Good contact with pad terminals.

[0006]

FIG. 1 shows an embodiment of the present invention. The wafer 1 to be inspected is placed on the inspection stage 4 and XYZ (not shown)
It is moved in the X or Y direction by the moving mechanism, and moves up and down in the Z direction. Above the wafer 1, a head 5a and a fixing ring 5b
A test head 5 is provided, and the periphery of the probe card 3 is fixed to a fixing ring 5b using mounting bolts 5c. On both sides of the opening 3a of the probe card 3, the warp detecting piezoelectric elements (A) 61 and (B) 63 and the warp correcting piezoelectric elements (A) 62 and (B) 64 are symmetrically arranged, and the warp is detected. Each piezoelectric element is adhered to the surface of the probe card 3 so that can be detected or corrected without fail. Each piezoelectric element is connected to the correction voltage generation circuit 7. The reason why the piezoelectric elements are arranged symmetrically on both sides of the opening 3a is that the warpage is not always balanced on both sides, so that this is reliably corrected. FIG. 2 shows a schematic configuration of the correction voltage generating circuit 7, in which phase inverters 71 and 73 for inverting the phases of the detection voltages of the warp detecting piezoelectric elements (A) 61 and (B) 63, and the respective output voltages The amplifiers 72 and 74 adjust the levels to appropriate levels, and the outputs of the amplifiers are supplied to the warpage correction piezoelectric elements (A) 62 and (B) 64 as correction voltages, respectively.

A method for correcting the warpage of the probe card 3 and a method for inspecting the LSI chip 2 will be described with reference to FIGS. 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 moved up in Z to bring each pad terminal 2a into contact with the corresponding probe 3c. The warp generated in the probe card 3 due to the influence of the heating on the wafer 1 is detected by the warp detecting piezoelectric elements (A) 61 and (B) 63, respectively. Each detection voltage is input to the correction voltage generation circuit 7, and a correction voltage of an appropriate level is output in the opposite phase to the detection voltage. Or it is corrected close to this. By this correction, each probe 3
c reliably contacts the corresponding pad terminal 2a, and the LSI chip 2 is inspected with reliability.

[0008]

As described above, in the probe card warp correcting mechanism 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 detecting piezoelectric element and detected by the correction voltage generating circuit. Generates a correction voltage in phase opposite to that of the voltage and supplies it to the warpage correction piezoelectric element, corrects the warpage of the probe card, and reliably contacts the probe of each probe pin to the corresponding pad terminal of the LSI chip. There is a big thing which contributes to the inspection of the LSI chip with a possibility.

[Brief description of the 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 illustrating an example of a probe card for LSI inspection, and FIG. 3C is an explanatory diagram of an LSI chip inspection method using a probe card; is there.

FIG. 4 is an explanatory diagram of a contact failure due to a warp of a probe card.

[Explanation of symbols]

DESCRIPTION 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 ... Warpage detecting piezoelectric element (A), 63 warpage detecting piezoelectric element (B), 62 warpage correcting piezoelectric element (A), 64 warpage correcting piezoelectric element (B), 7 correcting voltage generation circuit, 71, 73. Phase inverter, 72,74 ... amplifier.

Claims (1)

(57) [Claims] Respect 1. A LSI chip pad terminals formed on the wafer, carried out by contacting the probe pins of the probe card is used in the inspection of the LSI chip
A warp correction mechanism of the probe card that is disposed on the surface of the flop <br/> probe card before the rise of the test temperature
A warp detector piezoelectric element for detecting a warp occurring in serial probe card, wherein in parallel with the warp detection piezoelectric element Purobuka
And the warp correction piezoelectric element for correcting giving a reverse force to the warp of the surface provided on the surface of the over-de, the detection voltage of the warp detection piezoelectric element is input, the detection voltage and the opposite phase of the correction voltage characterized in that it comprises a correction voltage generation circuit for supplying the previous SL warpage correcting the piezoelectric element to generate a probe card of the warp correction mechanism.