KR100356823B1 - Probe card - Google Patents

Abstract

The present invention relates to a probe card for use in a wafer level burn-in test apparatus.

A probe card comprising a probe board installed in a wafer burn-in test apparatus for receiving an external test signal and transferring the signal through an internal circuit to a signal transmission means through a signal output terminal. Is a disk-shaped body of elastic material formed with a plurality of through holes; It consists of elastic conductive pins inserted in each through hole, and the upper and lower ends of each elastic conductive pin are in contact with the lower surface of each signal output terminal and the upper surface of the chip pad of the wafer to be tested, so that test signals are transmitted from the probe board to each chip pad of the wafer. It is characterized by being supplied with.

Description

Probe card {PROBE CARD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card used in a wafer level burn-in test apparatus, and more particularly, to a probe card that enables continuous use while effectively performing a wafer level burn-in test.

The probe card consists of a probe board on which a circuit is formed, and an electrical connection means for electrically connecting the pads of the semiconductor chip to be tested and the circuits on the probe board. The probe card electrically connects the tester and the semiconductor chip pad to test whether there is an abnormality of the semiconductor chip. I would have to.

Semiconductor chips are only shipped if they are tested and found to be of good quality before being shipped to the end consumer.

Among them, the burn-in test takes a lot of time under normal use conditions, so the product is tested in an environment where the use conditions are much worse.

In other words, by raising the temperature (above 125 ℃) and applying a voltage higher than the normal operating voltage (5.0V), a product that is likely to cause defects is selected within a predetermined time. The burn-in test is intended to stress the product and to check for the initial failure before shipping, and the general burn-in test was carried out at the package level.

However, in recent years, the burn-in test at the wafer level which can discriminate the defect of a chip | tip early in a wafer processing state is common.

Burn-in testing at the wafer level requires testing of all chips formed on the wafer at one time, so a full contact improves on a probe card with a conventional probe needle structure that could not test the entire chip formed on the wafer. Several probe cards have been developed for full contact, ie to test all the chips on a wafer at once.

The structure of a conventional probe card for wafer 9 level burn-in test will now be described.

1A is a perspective view showing the top surface of the probe board and FIG. 1B is a perspective view showing the bottom surface of the probe board. 2 is a partial perspective view of a contact sheet used in a conventional probe card, FIG. 3A is an exploded sectional view of a conventional probe card, and FIG. 3B is a sectional view showing a conventional probe card mounted in a wafer boat.

The conventional probe card has a conductive board 5 which electrically connects a probe board 1 having a circuit 1-1 and a plurality of chip pads 10 formed on the wafer 9 to be tested with the circuit of the probe board. ) Is formed of a contact sheet 4 formed with an elastic dielectric plate 6 interposed between the contact sheet and the probe board 1 for buffering and vertical conduction.

A plurality of first terminals 2 and second terminals 3 protrude from the bottom surface of the probe board 1.

The first terminal 2 and the second terminal 3 are electrically connected to each other in the probe board 1, and the first terminal 2 is densely formed in the center of the probe board 1.

In addition, the second terminal 3 is circularly distributed around the outside of the first terminal group 2 and grouped and distributed, and is electrically connected to the test signal generator 7 during the test.

The diameter of the probe board 1 is longer than the diameter of the wafer 9 so that the second terminal can contact the test signal generator 7.

The contact sheet 4 is a thin sheet of the size of a wafer 9, in which a plurality of conductive bumps 5 whose surface is plated are protruded upwards and downwards.

An elastic dielectric plate 6 configured to be insulated in the X and Y axial directions and electrically conductive only in the Z-axis direction, that is, the up-down direction, is joined to the upper surface of the conductive ridge 5.

The contact sheet 4 bonded to the elastic dielectric plate 6 is interposed between the probe 9 and the wafer 9 placed on the hot-chuck 8, and the first terminal of the probe board. 2 and the chip pad 10 on the wafer 9 are electrically connected through the conductive bumps 5 and the elastic dielectric plate 6.

In addition, since the first terminal 2 is electrically connected to the second terminal 3 and the second terminal 3 is electrically connected to the test signal generator 7, burn-in test is possible.

The burn-in test involves placing a wafer 9 to be tested on a hot chuck 8 formed in a wafer boat 15 in a wafer burn-in apparatus (not shown), then aligning and placing electrical contact positions between the respective components, and then placing a wafer boat ( The press jig 18 for pressurizing the upper surface of the probe board 1 to a predetermined pressure to maintain contact.

The thermal expansion coefficient of the probe board 1 is the same as the thermal expansion coefficient of the wafer 9.

However, the plurality of conductive bumps 5 formed on the contact sheet 4 used in the above-described conventional probe card are plated and cannot be used continuously because they melt after one use due to high heat and contact pressure. Replace and discard used products. Thus, there was a significant cost loss.

In addition, when heat is applied, deformation occurs in the wafer 9. In particular, the bumps of the chip pad 10 and the contact sheet 4 on the wafer 9 which are in contact with each other due to the deformation in the z-axis direction are separated from each other. There was a problem that it is difficult to carry out accurate testing.

Accordingly, it is an object of the present invention to provide a probe card which can be used repeatedly during the wafer level burn-in test without replacement of the contact sheet and which enables a continuous electrical connection between the probe board and the wafer chip pad during the test.

The technical means of the present invention for achieving the above object is a probe board installed in the wafer burn-in test apparatus for receiving an external test signal and transferring the signal via the internal circuit to the signal transmission means through a signal output terminal; A probe card comprising: a signal transmission means comprising: a disc-shaped body of elastic material having a plurality of through holes; It consists of elastic conductive pins inserted in each through hole, and the upper and lower ends of each elastic conductive pin are in contact with the lower surface of each signal output terminal and the upper surface of the chip pad of the wafer to be tested, so that test signals are transmitted from the probe board to each chip pad of the wafer. It is characterized by being supplied with.

In addition, the disk-shaped body is characterized in that the coefficient of thermal expansion is the same as the wafer and using the pogo pin as the elastic conductive pin.

1A and 1B are top and bottom perspective views of the probe board, respectively

2 is a partial perspective view of a contact sheet used in a conventional probe card

Figure 3a is an exploded cross-sectional view of a conventional probe card

3B is a cross-sectional view of a conventional probe card mounted in a wafer boat.

4A to 4C show a contact disc of a probe card according to the present invention;

5A is an exploded cross-sectional view of a probe card according to the present invention.

Fig. 5B is a sectional view of a probe card according to the present invention mounted in a wafer boat.

<Description of the symbols for the main parts of the drawings>

1: probe board 2: first terminal 3: second terminal

24: contact disc 25: elastic conductive pin 26: upper conductive pin

27: lower conductive pin 28: hot chuck 29: test signal generator

30: wafer 31: chip pad 32: spring

33: through hole 35: wafer boat 38: pressing jig

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4A to 4C show a contact disc of a probe card according to the present invention, FIG. 5A is an exploded cross-sectional view of the probe card according to the present invention, and FIG. 5B shows a probe card according to the present invention mounted in a wafer boat. It is a cross section.

The probe card of the present invention is installed in a burn-in test apparatus and used to test whether a plurality of chips formed on a wafer are defective.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated.

The probe card of the present invention has an elasticity that electrically connects a probe board 1 having a circuit formed therebetween, and a chip 31 on the wafer to be tested and a circuit formed on the board interposed between the wafer 30 to be tested and the board 1 to be tested. It consists of a contact disc 24 including a conductive pin 25.

The wafer 30 to be tested is placed on a hot-chuck (HOT-CHUCK) 28 in the wafer burn-in test apparatus 35.

Each chip formed on the upper surface of the wafer 30 has a pad 31 for electrical connection with the outside.

The probe board 1 is a flat board composed of a circuit, and a plurality of electrical terminals 2 and 3 are formed on the bottom surface.

The plurality of electrical terminals 2 and 3 formed on the probe board 1 include a first terminal 2 electrically connected to a circuit formed in the probe board, and a test signal generator of the wafer burn-in test apparatus 35. 29) in contact with the second terminal (3).

The first terminal 2 is formed to protrude in the center of the lower surface of the probe board 1.

In addition, the second terminal 3 is formed outside the center portion in which the first terminal 2 on the lower surface of the probe board 1 is formed.

The first terminal 2 is electrically connected to a circuit formed in the probe board 1, and the first terminal 2 and the second terminal 3 are electrically connected to each other in the probe board 1.

In addition, the second terminal 3 is in contact with the test signal generator 29 and electrically connected.

A contact disc 24 is interposed between the wafer 30 and the probe board 1 placed on the hot chuck 28.

The contact disc 24 is a disc about the size of the wafer 30 to be tested.

A plurality of upper and lower through holes 33 are formed in the disc, and a POGO PIN (registered trade name) 25 is inserted into each through hole.

The pogo pin 25 inserts a spring 32 between the upper and lower conductive pins 26 and 27 connected to each other to impart elastic force to the pin.

In addition, as the material of the disc, the thermal expansion coefficient is the same as the thermal expansion coefficient of the wafer, and the rubber material is used to have elasticity.

This is to maintain a continuous adhesive state even if deformation occurs in the wafer due to heat during the burn-in test process.

Each lower conductive pin 27 is in contact with each chip pad 31 on the wafer and each upper conductive pin 26 is in contact with the first terminal 1 of the probe board 1.

Hereinafter, the operation of the wafer burn-in apparatus of the present invention will be described.

The wafer 30 to be burned-in test is placed on the wafer hot chuck (HOT-CHUCK) 28 installed in the wafer burn-in test apparatus 35.

A plurality of chip pads 31 are formed on the upper surface of the wafer 30.

Each pogo pin 25 of the contact disc 24 contacts the wafer 30 so as to correspond to each pad 31 of the wafer 30 to be tested.

At this time, each pad 31 on the wafer contacts the lower pin 27 of each pogo pin 25.

Then, the upper pin 26 of each pogo pin 25 in the contact disc 24 and the first terminal 2 of the probe board 1 come into contact with each other.

Subsequently, the upper surface of the probe board 1 is pressurized using a pressure jig 38 of the wafer burn-in test apparatus at a predetermined pressure to firmly contact each contact portion, and the terminal of the test signal generator 29 and the probe board 1 Contact the second terminal (3).

The test signal generator 29 generates a signal and transmits the signal to each chip in the wafer through the second terminal 3, and at the same time, the test is performed while the hot chuck 28 applies heat to the wafer.

Looking at the electrical connection path of each chip in the wafer 30 and the test signal generator 29 as follows.

The electrical signal generated by the test signal generator 29 is transmitted to the first terminal 2 through the second terminal 3 of the probe board 1. The first terminal is connected to a circuit (not shown) formed on the probe board 1 and is in contact with the upper pin 26 of the pogo pin 25 protruding to the upper surface of the contact disc 24.

The electrical signal transmitted through the upper pin 26 to the lower pin 27 is transmitted to each chip on the wafer 30 through the chip pad 31 in contact with the lower pin.

In addition, the thermal expansion coefficient of not only the probe board 1 but also the contact disk 24 is the same as the thermal expansion coefficient of the wafer 30, so that the same deformation as the thermal deformation of the wafer 30 occurs with respect to the applied heat. 24) is made of an elastic material, and the pogo pin 25 also has elasticity, so it absorbs the impact caused by pressure, and even if a z-axis deformation occurs during the test, the contact state can be maintained until the end of the test.

As described above, the present invention replaces the conventional contact sheet and the elastic dielectric plate used in the wafer burn-in test with a contact disk in which pogo pins are inserted into an elastic disk, thereby bringing enormous cost savings. .

In addition, since elastic pins, in particular, pogo pins, are used as the means for electrically connecting the terminals of the probe board and the chip pads on the wafer, respectively, the elasticity is maintained even when vertical deformation occurs due to thermal deformation during testing. It maintains the contact state by using it, which has the effect of enabling more accurate testing.

Claims (3)

A probe card installed in a wafer burn-in test apparatus, the probe card comprising a probe board receiving an external test signal and transferring the signal through an internal circuit to a signal transmission means through a signal output terminal. The signal transmission means includes a disk-shaped body of elastic material having a plurality of through holes; It is made of an elastic conductive pin inserted in each through hole, The upper and lower ends of the elastic conductive pins respectively contact the lower surface of each signal output terminal and the upper surface of the chip pad of the wafer to be tested to supply the test signal from the probe board to each chip pad of the wafer. Card. The method according to claim 1, And said disc-shaped body has the same coefficient of thermal expansion as a wafer. The method according to claim 1, Probe card, characterized in that using the pogo pin as the elastic conductive pin