JPS60239037A - Semiconductor wafer prober - Google Patents

Abstract

PURPOSE:To prevent the contamination of a non-defective chip by ink by a method wherein, when the semiconductor wafer for which a measurement has been finished is going to be conveyed from the top of a wafer chuck to a cassette, an inflared ray lamp is provided between them, and the ink applied to the surface of the defective chip is dried up. CONSTITUTION:A fully-automatic semiconductor wafer prober consists of a probing machine part and a wafer coveying part, the cassettes CA1 and CA2 whereon wafers are multistage-stacked are moved vertically by the elevator mechanism provided on the conveying part, the wafers are moved to a round belt conveyor BC, and then they are transferred to a machine part. Also, an X-Y table TB, a Z-table which is not shown in the diagram, and an image pickup device ITV are provided on the machine part and besides, a microscope MS and a CRT (cathode-ray tube) adjoining to the microscope are arranged on the Z- table. Through these procedures, the characteristics of the wafers placed on the Z-table are measured using the prober, and if there is a defective article, ink is applied thereon, and the ink is dried up while the wafer is being conveyed to the cassette using an inflared ray lamp LAP.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor wafer prober, and relates to, for example, a technique effective for use in a fully automatic semiconductor wafer prober.

[Background technology]

Semiconductor wafer probers, which are responsible for the final checking process of semiconductor wafers, have become so-called tweezers-less, in other words, due to the difficulty of manual work using tweezers, sotresses, or other tools, as semiconductor wafers have become larger in diameter. For example, automatic loading and unloading of semiconductor wafers is described in "Electronic Materials J Magazine, November 1978 issue, page 139.
~ page 143. That is, from a storage container (cassette) containing a plurality of semiconductor wafers (for example, 25 wafers), the semiconductor wafers stored there are transferred one by one by a round belt conveyor to a load stage (:
'J-S alignment stage). and,
This semiconductor wafer is transferred to a suction table (yI!I fixed table) of a blobbing machine section using a Bernoulli chuck or the like. Next, the semiconductor wafer for which the measurement has been completed is carried out from the suction table to the unloading stage by blowing air pressure or the like, and is placed in a storage container by a round belt conveyor. As described above, the semiconductor wafer is carried into and out of the blobbing machine section in a completely non-contact state with respect to the surface of the semiconductor wafer.

By the way, if there is a defect in each semiconductor integrated circuit completed on a semiconductor wafer, marking is applied to select it. For example, marking is performed using ink containing a magnetic substance, the semiconductor chips are divided into individual semiconductor chips, and then the defective chips are removed using a magnet. When semiconductor wafers that have been marked with such markings are stored in a cassette, the ink from the defective chip adheres to the surface of the adjacent good chip through the slit into which the end of the semiconductor wafer is inserted. This causes the problem of contaminating the surface. In addition, if ink remains attached to the slit of the cassette, when the cassette is used to store unmeasured semiconductor wafers, the ink powder may adhere to the surface of the unmeasured semiconductor wafer, causing the probe needle and the A problem arises in that this results in poor contact. In other words, when a thin wire probe needle is pressed against the bonding pad of a semiconductor integrated circuit completed on a semiconductor wafer to send and receive signals, if a contact failure occurs, a good semiconductor integrated circuit will become a defective one. A problem arises in that the cost spent in the masked wafer process is wasted, or in other words, the yield of semiconductor integrated circuit devices is deteriorated and the cost I is increased.

[Purpose of the invention]

An object of the present invention is to provide a semiconductor wafer prober that achieves highly reliable measurements.

The above and other objects and novel features of this invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, the semiconductor wafer after measurement is placed in a predetermined position until it is transferred from the wafer chuck top to the cassette.
A heater is provided to dry the ink adhered to the surface of the defective chip.

〔Example〕

FIG. 1 shows an external view of an embodiment of a fully automatic semiconductor wafer prober to which the present invention is applied.

The fully automatic semiconductor wafer prober shown in the figure can be roughly divided into a blowing machine section and a semiconductor wafer transfer section. The semiconductor wafer transfer section includes cassettes CAI and CA that store a plurality of semiconductor wafers in a multi-stage configuration in the vertical direction.
2, and a round belt conveyor BC for transferring the semiconductor wafers between the elevator mechanism and the loading stage and unloading stage for the blowing machine section.

The load stage is provided with means for rotating the semiconductor wafer transferred thereto and detecting its orientation flat, and performs a preliminary operation of positioning the semiconductor wafer in the θ direction.

On the other hand, although the blobbing machine part is not visible from the outside,
It is composed of an X-Y table X-YTB. This X-
A wafer chuck top (semiconductor wafer mounting table) is attached to the Y table X-YTB, which is driven by a pulse motor to perform precise position control. The wafer chuck top has a suction hole for vacuum suctioning the semiconductor wafer, and a blow-off hole for transporting the semiconductor wafer after measurement to the unloading stage (which may also be used in conjunction with the suction hole described below). ) is provided. The wafer desktop is also equipped with a Z stage, which pushes up the semiconductor wafer against the probe needles of the fixed probe board attached to the opening at the top of the X-Y table X-YTH. Electrical contact is made between the bonding pad of the wafer and the contact end of the probe needle.

The B-Q fTh mirror MS is used to ensure alignment (needle alignment) between the contact end of the probe needle and the surface of the semiconductor wafer through the above-mentioned aperture, or to ensure that the automatic alignment described later is not working properly. This is to be used for observing preliminary manual needle alignment at times.

The semiconductor wafer whose orientation flat has been detected on the load stage is transferred to the wafer chuck top, which is moved to the load position by a transfer arm as described in f&. Above this load position, an imaging device ITV consisting of a television camera or the like is provided in order to realize automatic needle adjustment. The digitized circuit pattern signal of the semiconductor wafer formed by the image pickup device ITV is subjected to a pattern recognition operation by an image processing device (not shown), and the position of the bonding pad is identified. The display device CRT mainly displays its monitor screen.

The operation panel PNL is used to input various manual control signals such as starting and stopping the above operations.

FIG. 2 shows a schematic diagram of the main internal mechanisms of the fully automatic semiconductor wafer prober shown in FIG. 1 above. Therefore, the microscope MS, display device CRT and imaging device ITV in FIG. 1 are not shown.

As described above, the blobbing machine section moves the wafer chuck top CT, which suctions and fixes the semiconductor wafer placed on the upper surface thereof, to X, Y by the X-Y table X-YTB.
By moving in the direction or rotating in the θ direction,
It consists of a fixed probe board or the like, and the tips of the probes are aligned with the bonding pads of the wafer chip (semiconductor integrated circuit) with the probe needles arranged in correspondence with the measurement points. In this positioning, although not particularly limited, at the load position LP, the semiconductor wafer is rotated in the θ direction to perform alignment, that is, the alignment of the chips on the semiconductor wafer.
The axis is made to coincide with the X-axis of the above-mentioned X-Y table X-YTB. Furthermore, the position of the bonding pad is detected by the pattern recognition operation. Based on this position detection data, the position of the bonding pad is calculated when the semiconductor integrated circuit (chip) to be measured first on the wafer chuck top CT is moved to the position of the probe needle on the fixed probe board. Automatic needle adjustment is performed. This automatically aligns the tip of the probe needle with the bonding pad of the first wafer chip to be measured. Thereafter, by continuously moving the probe in the X direction or the Y direction at intervals of one chip at a time, the probe is automatically aligned with the bonding pads of other wafer chips. These X-Y tables X-YT
Movement control of B is performed with high precision using a pulse motor. Further, the wafer chuck top CT is moved in two directions (up and down) using air or a pulse motor. That is, the positioning operation by the X-Y table X-YTB is performed with the wafer chuck top CT lowered, and during measurement, the wafer chuck top CT is
With the probe needle pushed up, the probe needle and the bonding pad of the wafer chip are brought into contact with the required contact pressure to establish an electrical connection.

Since such a stage mechanism is well known, a more detailed explanation will be omitted.

The transfer arm TB uses, for example, a Bernoulli chuck that sucks the semiconductor wafer below the surface without contact, and transfers the semiconductor wafer transferred to the load stage LS to the wafer chuck top CT, which has been moved to the load position LP. do. In addition, after the wafer chuck top CT is moved to the unload position UL, the semiconductor wafer after the measurement is transferred to the unload stage US of the transfer section by blowing out air or the like from the suction port of the wafer chuck top CT. It will be transported to

A semiconductor wafer transfer section is provided for such a blobbing machine section equipped with an automatic semiconductor wafer loading/unloading mechanism. The semiconductor wafer transfer section in this embodiment includes four elevator mechanisms E1 to E4 in which storage containers (cassettes) CAI, CA2, etc. as shown in FIG. 1 are installed to store semiconductor wafers, and a course alignment stage. A round belt conveyor BC is provided which connects the load stage LS and the unload stage US, which also operate as a load stage LS and an unload stage US.

In the figure, this round belt conveyor consists of a pair of round belts B1 running vertically in the center of the transfer section, and this round belt B1.
, four pairs of round bells (B2-B5) running perpendicularly on the right side and connecting between the elevator mechanisms E1 to E4, and a round belt B1 running in the center, on the left side thereof. Two pairs of round belts B6. each run at right angles and connect between the load stage LS and unload stage US. It is composed of BT. Each of the round belt conveyors B1 to B7 is provided with a driving pulley and a free pulley at both ends, and a motor (not shown) drives the driving pulley via a similar round belt. A conveyor consisting of a pair of round belts runs, and the semiconductor wafers placed on it are transported. Guides (not shown) are provided on both sides of these pair of round belts. This prevents the semiconductor wafer from falling off the pair of round belts. Additionally, a sensor (shown) is installed at the transfer point (connection point) of semiconductor wafers between the round belt conveyors.
will be established. Although not particularly limited, this sensor is configured by an optical sensor and detects the semiconductor wafer transferred to the top thereof. For example, when a semiconductor wafer to be measured is transferred from top to bottom by the round belt conveyor B1 running in the center, the sensor detects that the semiconductor wafer has been transferred to the position where it is connected to the load stage LS. Then, the transfer operation of the round belt conveyor B1 running in the center is stopped.

When the operation of the round belt conveyor B6 connected to the load stage LS is started, it transfers the semiconductor wafer and transfers it to the load stage LS. The other semiconductor wafer transfer operations are also similar to those described above, so their explanations will be omitted. Further, since the elevator mechanism E1 and the like are well known, for example, from Japanese Patent Application Laid-Open No. 54-48482, a detailed explanation thereof will be omitted.

In this embodiment, in order to dry the marking ink attached to the surface of the semiconductor wafer on the unloading stage US or the round belt conveyor connected thereto, a heater (not shown in the figure) as described below is installed. is provided.

FIG. 3 shows a schematic sectional view of one embodiment of the heater.

Although not particularly limited, in this embodiment, the following heaters 1 and AP are provided above a round belt conveyor B7 consisting of a pulley P and a round belt. That is, the heater LAP is not particularly limited, but an infrared lamp may be used. Further, although not shown, when a sensor detects that the semiconductor wafer W has been carried out to the unload stage US, a drive current is supplied to the heater LAP. Thereby, when the semiconductor wafer W is transferred by the round belt conveyor B7, the marking ink attached to the surface of the semiconductor wafer 2 wafer W is dried at high speed by the radiant heat. In order to ensure this drying, the transfer speed of the round belt conveyor B7 is set to be relatively slow compared to other round belt conveyors, although this is not particularly limited. Then, the semiconductor wafer W is connected to the heater LA.
When it passes under P, a sensor (not shown) detects this and stops supplying the driving current to the heater. This reduces wasteful radio wave consumption.

〔effect〕

(11) Before the semiconductor wafer that has been measured is transferred to the cassette, the marking ink is dried by a heater.This allows the marking ink to be removed from the defective chips when the semiconductor wafer that has been measured is placed in the cassette. This has the effect of preventing adjacent non-defective chips from being contaminated by ink.

(2) Since the marking ink for semiconductor wafers that have been measured is dried, the marking ink will not adhere to the slits of the cassette in which it is stored, so the cassette can be used to store semiconductor wafers that have not yet been measured. During use, it is possible to prevent the residue of the marking ink from adhering to the surface of a semiconductor wafer that has not been measured. This provides the effect that poor contact between the probe needle and the bonding pad due to the ink scum can be prevented during the measurement.

(3) Due to the above (11 and (21), the number of good semiconductor integrated circuits that can be obtained from one semiconductor wafer increases, and the yield of semiconductor integrated circuit devices can be increased, so that the manufacturing cost can be reduced. This effect can be obtained.

(4) When performing automatic needle adjustment based on pattern recognition,
(1) prevents marking ink scum from adhering to the semiconductor wafer surface, so minute ink scum can be used as a circuit pattern! ! The effect is that it is possible to prevent erroneous operations such as weaving or unnecessary operations until searching for the desired pattern.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that this invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, the heater may be configured to blow hot air generated by heating clean gas such as dry nitrogen onto the surface of the semiconductor wafer. Further, these heaters may be provided on the unloading stage.

Furthermore, the alignment of the probe to the semiconductor wafer is
It may be performed manually by visual inspection using a microscope. That is, after the semiconductor wafers that are automatically sent one after another from the transfer section are placed on the wafer chuck top, the first step is to visually measure the position of the bonding band of the semiconductor integrated circuit and the contact end of the probe holder. It may also be possible to perform Furthermore, the means for transferring the semiconductor wafers may be any means other than the nine-belt conveyor described above, such as an F-bearing.

In addition, in order to increase the versatility of the system, it is desirable that the operation control of the operating side of the probing machine section and the transfer of the semiconductor wafer be performed by program control using a microcomputer, etc., but it is not limited to this. Instead, it may be performed by a so-called hard logic circuit.

[Application field]

This invention can be widely used in semiconductor wafer probers.

[Brief explanation of drawings]

FIG. 1 is an external view of a semiconductor wafer prober according to the present invention, FIG. 2 is a schematic plan view of its interior, and FIG. 3 is a sectional view showing an embodiment of the heater. X-YTB...X-Y table, MS...microscope, CR
T...display device, ITV...imaging device, CAI
, CA2...cassette, PNL...operation panel, CT...
・Wafer chuck top, LS...Load stage, U
S...Unload stage, BC, Bl~B7...Round belt conveyor, 6 LAP...Heater, TB...Transfer arm Mitsumasa Mochiku, patent attorney

Claims (1)

[Claims] 1. A heater is provided at a predetermined position before the semiconductor wafer after measurement is transferred from the wafer chuck top to the cassette to dry ink adhered to the surface of the defective chip. Semiconductor wafer prober. 2. The semiconductor wafer prober according to claim 1, wherein the heater is an infrared lamp. 3. Claim 1 or 2, wherein the semiconductor wafer prober is a fully automatic semiconductor wafer prober in which loading/unloading of the semiconductor wafer to be measured into/from the blowing machine section is automatically performed. Semiconductor wafer prober described in Section 1.