JP2545648B2 - Prober - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a prober.

[0002]

2. Description of the Related Art Generally, in a semiconductor device manufacturing process, in order to efficiently test electrical characteristics of electronic circuits (chips) such as ICs and LSIs formed on a semiconductor wafer, each chip A prober is a device that makes it possible to automatically contact each electrode with a contactor and perform an electrical test of each chip by an external tester connected to the contactor, and also to identify the chip judged to be defective by the tester. in use. This prober has a probe card in which a needle such as tungsten is fixed using a ceramic guide on a base formed by laminating copper foil on epoxy or polyimide etc., and this tungsten contact is inspected. By making contact with the electrode pad of the IC, the I
It is designed to inspect C. By the way, as a screening test of a semi-finished semiconductor device, in addition to conducting an electrical test of the semiconductor device using the prober at room temperature to room temperature, a temperature stress or a voltage stress is applied to the semiconductor device at a high temperature. Burn-in is being carried out except for devices with inherent defects and latent defects.

To carry out this burn-in, the semiconductor wafer is warmed in a burn-in chamber and then taken out of the chamber, and only one chip in the semiconductor wafer is probed, and this is repeated many times. I was trying to test all the chips. Further, in order to improve the test efficiency, a probe has been developed in which the size of the probe card is increased so that a large number of chips can be simultaneously contacted at once.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In a prober that contacts one chip at a time, the inspection time as a whole becomes very long, which is not efficient. Also, in the case of a probe that can simultaneously contact a relatively large number of chips at the same time, the inspection efficiency is certainly improved, but the size of the contact portion of the probe card is limited due to the restriction due to thermal expansion, There was a limit to the number of chips that could be contacted at once. For example, if the minimum size of the electrode pad of the IC to be measured is 100 μmφ and the allowable dimensional error is about 30 μm, then one side of the probe needle in consideration of the temperature difference during burn-in at 125 ° C. Length is 4
Within 5 mm square. If multiple chips of VLSI (memory of IM or more) are to be simultaneously measured under this condition, the number of chips that can be collectively measured will be controlled by the length of one side. That is, in a probe card made of resin or the like, in particular, in a high temperature test such as burn-in in which the measurement condition temperature has a large difference from room temperature, expansion and contraction determined by the linear expansion coefficient occurs. In a VLSI device or the like in which the distance is narrow, the distance between the probe needles changes greatly, and in the worst case, it is predicted that the probe needles cannot contact the pads of the IC to be measured. For example, the distance between the two points of the semiconductor wafer is set to 130 mm, and the temperature measurement conditions for the wafer-scale probing are from room temperature 25 ° C. to 150 ° C.
When it is considered that the probe needle is heated to 0 ° C., the thermal expansion between these two points becomes 100 μm, and if the size of the pad is 200 μmφ or less, the probe needle may not be in contact.

[0006] Recently, the electrode array length of one side of a single object to be inspected is 100 mm like an LCD (liquid crystal display) substrate.
Some have exceeded the limit, and such long wafers or substrates cannot be collectively contacted. Further, when a cold probe needle at room temperature comes into contact with a semiconductor wafer that has been heated to a high temperature of 150 ° C., for example, the rigidity of the probe needle changes, so the contact condition also changes, which affects the measurement results. Therefore, there is also a problem that in order to avoid this effect, the measurement must be refrained from becoming stable. The present invention
It was devised to pay attention to the above problems and effectively solve them. An object of the present invention is to provide a prober capable of compensating the dimension between electrodes of a device under test and the dimension between contacts of a prober even at high temperature.

[0007]

In order to solve the above-mentioned problems, the present invention has a large number of contacts held by a holding member and makes contact with a plurality of electrodes of a device under test in a high temperature state. In a prober for electrically testing an object to be inspected by contacting a child indirectly or directly, heating means provided in the holding member, and first temperature detecting means for detecting the temperature of the holding member, By controlling the heating means based on the second temperature detecting means for detecting the temperature of the inspection object, and the output value of the first temperature detecting means and the output value of the second temperature detecting means. A temperature control means for controlling the temperature of the holding member is provided.

[0008]

Since the present invention is configured as described above, the temperature of the object to be inspected, which is maintained at a high temperature for burn-in, is detected by the second temperature detecting means, and the value is input to the temperature control means. In this temperature control means, in consideration of the coefficient of linear expansion of, for example, the linear expansion coefficient of the object to be inspected and the coefficient of linear expansion of the contact, for example, the distance between the contacts can be set to the distance between the electrodes of the object to be inspected. The temperatures of the holding members at which the intervals are matched are stored in a table, for example. Therefore, the temperature control means obtains a value corresponding to the input value from the table, and operates the heating means provided on the holding member so that the value becomes the value. The temperature of the holding member is the first
It is monitored by the temperature detection means and fed back to the temperature control means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the prober according to the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the prober 2 has a printed circuit board (PCB) 4 as a holding member formed by laminating, for example, a copper foil on a resin such as epoxy or polyimide. A pattern 8 made of, for example, copper having good conductivity is formed on the lower surface of the via a flexible printed circuit (FPC) 6 having flexibility. On this copper pattern 8, a plurality of chips 12 formed on a semiconductor wafer 10 as an object to be inspected, and a plurality of convex electrodes 14 such as bumps, respectively, are provided so as to be opposed to each other.
Many 6 are formed, for example, several thousand. Further, the lower surface of the copper pattern 8 is filled with contact particles all over the surface, and a conductive rubber connector 18 is provided over the entire surface so that when a predetermined pressing force is applied, only the pressed portion is electrically connected in the pressure direction. By pressing the conductive rubber connector 18 between the contactor 16 and the convex electrode 14 at the time of inspection, they can be indirectly contacted with each other to bring this portion into a conductive state. Also, the FPC6 is
It is connected to a tester (not shown) by a lead wire 20 and the like, and is configured to perform an electrical test of the chip 12.

The semiconductor wafer 10 is attached to a chuck plate 22 such as a hot chuck for fixing the semiconductor wafer by suction or the like. The chuck plate 22 has a semiconductor for burn-in test. A heater 24 for heating the wafer and a second temperature detecting means 26 for detecting the temperature of the semiconductor wafer at that time are provided. On the other hand, the holding member 4 is provided with heating means 28 for heating the holding member 4. The heating means 28 is composed of a block 32 having a certain heat capacity in which a heater 30 is embedded, and the first temperature detecting means 25 is embedded in the block 32 so as to measure the temperature of the holding member 4. ing. And
The output values of the first and second temperature detecting means 25 and 26 are
It is input to the temperature control means 34 side, and the heating means 28 is driven based on these input values to control the temperature of the holding member 14. Specifically, the temperature control unit 34 includes a variable voltage source 36, a PID control unit 38 including, for example, a microcomputer, a pulse width modulator 40 connected to the control unit 38, and the modulator 40. Is mainly configured by a driver 42 that actually drives the heater 30 by the output of the above.

Here, the microcomputer or the like of the control unit 38 takes into account the thermal expansion coefficient or linear expansion coefficient of the semiconductor wafer and the thermal expansion coefficient or linear expansion coefficient of the FPC 6 or the holding member 4 holding the contactor 16. Then, the temperature of the holding member 4 is determined in advance so that the position of the electrode 14 of the chip 12 and the position of the contact 16 of the prober 2 with respect to the semiconductor wafer temperature at the time of burn-in match each other. have. For example, 12 burn-in tests
When performing at 5 ° C and 150 ° C, find the bump position for each temperature and use the prober 2 at this bump position.
The temperatures on the side of the holding member 4 when the contacts of the above are coincident, for example, 125 ° C. and 170 ° C. are obtained in advance and the correlation of these temperatures is stored in the ROM. The burn-in test temperature is 2 above.
Of course, the number of types is not limited and may be increased. Also,
When the burn-in test temperature is set in a range where both linear expansion coefficients are linear, the temperature on the side of the holding member 4 where the bump position and the contactor position match can be obtained by, for example, calculation taking the linear expansion coefficient into consideration. Therefore, the calculation function may be built in the control unit 38. Usually, the linear expansion coefficient of the holding member 4 side with respect to the semiconductor wafer 10 is ten times as large as that of the semiconductor wafer 10, so that it can be applied to any burn-in test temperature.
At the burn-in temperature of 0 ° C., it is preferable to initialize the prober side so that the contact member and the bump can be aligned in position by heating the holding member 4 side to the same temperature.

Next, the operation of this embodiment configured as described above will be described. First, when the burn-in temperature is set to, for example, 150 ° C., the heater 24 provided on the chuck plate 22 is operated to move the semiconductor wafer 10 to 150 ° C.
Heat to ° C. The temperature at this time is the second temperature detecting means 26.
Is detected by and is automatically input to the control unit 38 of the temperature control means 34. On the other hand, the controller 3 that receives the temperature input
8 is a pulse width modulator 40 prior to the burn-in test.
And the driver 42 is driven to operate the heater 30 of the heating means 28 to preheat the block 32, the holding member 4, the FPC 6 and the copper pattern 8 to a predetermined temperature. The heating temperature at this time is obtained from a table stored in advance in the ROM or the like in the control unit 38, and the holding member 4 is heated to 170 ° C., for example. At this time, the temperature on the holding member 4 side is monitored by the first temperature detection means 25 and is input as a feedback signal to the control unit 38, so that the set temperature of 170 ° C. is always maintained.

Therefore, the position of the contactor 16 of the prober 2, that is, the pitch width, is determined by utilizing the thermal expansion of the holding member 4 side.
The positions of the bumps 14 of the semiconductor wafer 10 at the time of burn-in or the pitch intervals are adjusted to match.
At this time, although the influence of thermal expansion of the conductive rubber connector 18 may be considered, no problem occurs because a grid-free connection is obtained with the chip side. Actually, the copper pattern 8
The FPC 6 and the holding member (PCB) 2 have a larger linear expansion coefficient, but the copper pattern 8 is stretched in accordance with the expansion, so that no problem occurs. In this way, it is possible to compensate for the pitch displacement of the bumps 14 on the chip during the burn-in test of the semiconductor wafer so that the pitch intervals of the contactors 14 on the prober 2 side match.

Therefore, it is possible to perform collective probing on an LCD substrate or a wafer scale having a long electrode array on one side by using a prober in which contacts are arranged over a length of, for example, 50 mm or more. In the above embodiment,
Although the convex portion formed on the copper pattern 8 is used as the contactor 16 of the prober 2, the present invention is not limited to this, and a probe needle 50 made of tungsten as shown in FIG. 3, for example, may be used.

Further, when the probe needle 50 is used, the temperature of the holding member 4 side may be controlled by the control unit 38 to be the same as the burn-in test temperature, or with a slight temperature difference. If the initial settings are made so that the pitch intervals of the prober needles 50 can be compensated, the temperatures of the semiconductor wafer 10 and the probe needles 10 become substantially the same before they come into direct contact with each other, so that there is almost no heat transfer after the contact. It is possible to prevent the rigidity of the prober needle from changing, and it is possible to secure a stable contact when the automatic drive S is applied. Further, in the above embodiment, the detected temperature of the semiconductor wafer 10 is automatically input to the control unit 38, but this is manually input to the control unit 38.
It may be configured to input to. Furthermore, it is needless to say that the present invention can be applied to the case where pads are used instead of the convex bumps 14 as electrodes.

[0016]

As described above, according to the present invention, the following excellent operational effects can be exhibited. It is possible to match the pitch interval of the contact on the prober side with the pitch interval of the electrodes of the device under test even at a high temperature such as burn-in. Therefore, it is possible to perform batch probing of an object to be inspected having a large size, that is, batch probing of multiple chips and batch probing of a single item having a large size per side such as an LCD device, and the inspection time can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a prober according to the present invention.

FIG. 2 is an enlarged view of a main part of the present invention.

FIG. 3 is an explanatory diagram when a prober needle is used as a contactor.

[Explanation of symbols]

 2 prober 4 holding member (PCB) 6 flexible printed circuit (FPC) 10 semiconductor wafer (inspection object) 12 chip 14 electrode (bump) 16 contactor 24 heating heater 25 first temperature detecting means 26 second temperature detecting means 28 heating Means 30 Heater 34 Temperature control means 36 Control unit 50 Probe needle

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G05D 23/24 G05D 23/24 N

Claims (1)

(57) [Claims] 1. An electrical test of an object to be inspected, comprising a plurality of contacts held by a holding member, the electrodes being indirectly or directly contacted with a plurality of electrodes of the object to be inspected in a high temperature state. In the prober for performing the above, a heating means provided on the holding member, a first temperature detecting means for detecting the temperature of the holding member, and a second temperature detecting means for detecting the temperature of the inspection object. A temperature control means for controlling the temperature of the holding member by controlling the heating means based on the output value of the first temperature detection means and the output value of the second temperature detection means. Characterized prober.