JPS63260143A - semiconductor wafer prober - Google Patents

Abstract

PURPOSE:To make theta regulation of a probe board needless by detecting an angle of the X or Y axes of the probe board with the X or Y axes of a stage mechanism for performing transit control of the dynamic X-axis and the Y-axis of the stage mechanism according thereto. CONSTITUTION:In order to detect theta slippage of both axes of a probe board PB to the X and Y axes of a stage mechanism, an image pickup device ITV 1 is provided on a Y-stage YS. After judging the coordinates of the first point PTI in a probe needle by a pattern recognition device PT, the stage mechanism is moved in the arrow direction by a fixed distance L. Then, the coordinates of the second PT 2 are found out so as to calculate the theta slippage by the device RT for supplying a calculation result theta to the stage control device STGC. The STGC forms a dynamic control signal x' of an X stage XS and a dynamic control signal y' of a Y stage YS for performing transit control corresponding to the dynamic axis X' and axis Y' rotated by the angle theta. Thereby, the thetafitting of the probe board is made needless.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor wafer blobber, and relates to a technique that is effective for use in, for example, a device equipped with a high frequency test head.

[Conventional technology]

When the wafer prober is completed, the semiconductor integrated circuits are placed on the semiconductor wafer in the shape of a substrate. Semiconductor integrated circuits completed on semiconductor wafers are used in a blowing process to check whether they satisfy the desired circuit functions, characteristics, etc., before being individually divided and pancaged. is a thick wafer prober. A semiconductor wafer prober applies a probe needle to a bonding pad of a semiconductor integrated circuit completed on the semiconductor wafer, supplies an input signal from a tester, and transmits an output signal from the semiconductor integrated circuit to the tester.

A high frequency test head is provided to measure the semiconductor chip at the high frequency described above. Regarding the technology for connecting such a high frequency test head and a probe board, there is, for example, Japanese Utility Model Application Laid-Open No. 62-14728.

[Problem that the invention seeks to solve]

In a semiconductor wafer prober, when the probe board is loaded, its X and Y axes are aligned with the X and Y axes of the X/Y stage mechanism on which the measurement stage (wafer chuck top) is mounted. It is necessary. because,
The X/Y stage mechanism moves in accordance with the pitch of the semiconductor chips arranged in the pattern of the substrate, so if the axis of the probe board and the axis of the stage mechanism have a rotation angle θ, the This is because a positional shift occurs between the probe needle and the bonding pad as the probe needle moves toward the semiconductor urchin by the X, Y stage mechanism. Above θ
In conventional semiconductor wafer probers for adjustment,
It requires a ring insert and adjustment means as described in the above publication.

For this reason, not only does the mechanism of the equipment to which the probe board is attached become complicated, but also, especially in the case of high-frequency test heads such as those mentioned above, the signal transmission path between the probe board and the probe board becomes substantially long. Deterioration occurs in the signal, and the upper limit frequency that can be tested is made relatively low.

An object of the present invention is to provide a semiconductor wafer prober that does not require θ adjustment of a probe board.

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.

[Means for solving problems]

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

That is, the angle between the X or Y axis of the probe board and the X or Y axis of the stage mechanism on which the measurement stage holding the semiconductor wafer is mounted is detected, and the dynamic X axis of the stage mechanism is adjusted accordingly. Movement control including θ adjustment is performed so that the Y-axis and the Y-axis coincide with the X-axis and Y-axis of the probe board.

[For production]

According to the above means, the movement of the stage mechanism is controlled in accordance with the axis of the probe board, so the mechanism for mounting the probe board is simplified, and the connection path with the high-frequency test head is also simplified accordingly. becomes possible.

〔Example〕

FIG. 1 shows a schematic side view of the main parts of a semiconductor wafer prober according to the present invention.

In this embodiment, although not particularly limited, the X/Y stage is arranged vertically. That is, the X stage moves laterally along the beam vertical plane. For this reason, although not shown in the drawings, the X stage supports relatively heavy devices including the Y stage mechanism and the Z and θ stages in a highly stable manner. Although not particularly limited, the beam on the lower surface of the X stage is parallel to the horizontal plane. It consists of a running linear slide mechanism. The linear slide mechanism (X-task) is moved in the horizontal direction with high precision by a screw pair with a screw shaft (lead screw) rotated by an X-drive pulse motor. Thereby, the X stage XS is moved after highly accurate position movement control according to the rotation angle of the pulse motor and the screw pitch of the screw shaft.

Y stage YS is mounted on the above X stage XS,
It consists of a similar slide mechanism that is moved in the vertical direction by a screw pair with a screw shaft whose rotation is controlled by a pulse motor for Y drive similar to the above. Thereby, the position movement of the Y stage YS mounted on the X stage XS is controlled with high precision in the X and Y directions along the vertical plane of the beam.

On the Y stage mechanism, there is provided a Z stage that moves up and down in a direction perpendicular to the surface (vertical plane) of the Y stage mechanism, and a measurement stage that has a θ stage function that rotates about the Z axis. Furthermore, although the measurement mounting table is not particularly limited, by providing a plurality of concentric grooves on its surface and a plurality of vacuum suction holes provided on the bottom of the grooves, the semiconductor wafer WF mounted on the surface of the measurement mounting table is provided. The back side of the paper is vacuum-adsorbed. The basic configuration of each of the stage mechanisms and the measurement platform can be similar to that of the horizontal type semiconductor wafer blower known from the magazine and the like, except for the special structure for making it vertical.

Further, since the semiconductor wafer blowbar is of a vertical type as in the above embodiment, although not particularly limited, the measurement mounting table has a central portion for loading and unloading the semiconductor wafer WF to be measured (not shown). is selectively pushed upward relative to its reference plane.

When loading and unloading the semiconductor wafer to be measured, the central portion is lifted, and the semiconductor wafer to be measured is attracted only by the central portion. Then, loading the semiconductor wafer/
The wafer is attached to a transfer arm that carries out carrying out, and the transfer arm has, for example, a U-shaped suction section that performs vacuum suction on the back surface of the semiconductor wafer to be measured except for the portion corresponding to the central portion. Using this transfer arm, the semiconductor wafer to be measured can be carried in and out of the measurement stage. In addition, in this application,
The above measurement S! The structure of the mounting table transfer arm is not shown because it is not directly related.

The technology related to the loading/unloading of semiconductor wafers and the stage mechanism in such a vertical semiconductor wafer prober is as follows.
This is described in detail in the applicant's earlier application (Japanese Patent Application No. 47913/1982).

In this example, the probe board PB is fixedly mounted. In other words, a conventional rotation adjustment mechanism such as a ring insert is unnecessary. An imaging device ITVI is attached to the Y stage YS to detect the θ deviation of the X and Y axes of the probe board PB (probe needle tip arrangement) with respect to the X and Y axes of the stage mechanism.

By being attached to the stage YS, the imaging device ITVI is moved to a predetermined position on the lower surface side of the probe board PB by movement control of the stage mechanism, and the imaging device ITVI is moved to a predetermined position on the lower surface side of the probe board PB.
B is photographed from the bottom side. In other words, the imaging device (1) TVI faces the tip of the probe needle and photographs it. As a result, firstly, by accurately focusing on the tip of the probe needle, it is possible to obtain a sharp video signal with a sharp tip. In this case, a blurred image of the bending part of the probe needle that is out of focus and the part extending to the support part will appear around the tip image, but only the sharp image of the center (tip part) will be processed. Therefore, the coordinates can be accurately determined by simple binary pattern processing by the pattern recognition device PT.

Then, as shown in FIG. 2, the pattern recognition device PT determines, for example, the coordinates (Xl) of the first point PTI in one (or a plurality of) probe needles.

After determining the position of Yl), move the stage mechanism in the Y (or The coordinates (X2.Y2) of the second point PT2 are determined by moving the second point PT2 by a certain distance.

Two measurement points PT1 at the tip position of the same needle as above. From the relative relationship between both coordinates (Xl, Yl) and (X2.Y2) at PT2, it is possible to calculate the θ deviation between the Y (or X) axis of the probe board and the Y (or Y axis) of the stage mechanism.

Such calculation of θ deviation is carried out by the pattern recognition device PT.
This is done by This calculation result θ is supplied to the stage controller 5TGC. When the stage control device 5TGC receives the movement control i signal in the X and Y directions of the stage mechanism from the above calculation result θ, the stage control device 5TGC corrects the above θ and adjusts the dynamic control signal X° of the X stage mechanism and the dynamic control signal X° of the Y stage mechanism. A control signal y'' is generated. As a result, movement control corresponding to the dynamic axes X'' and Y'' that are rotated by the angle θ with respect to the true Y-axis and Y-axis of the stage mechanism is performed. Ru. Note that the microcomputer, etc. included in the pattern recognition device PT is the same as the stage control device 5TGC.
It may also be used to form the control signals X' and yo. That is, from the movement command signal and the angle θ, the control signals X' and y'' that actually determine the amount of movement of the stage mechanism are formed. These control signals X and yo are output as a pulse train (number). 0 For example,
After the rotation angle θ is detected, a movement command in the X-axis direction is issued such that the robot is moved in the X′ direction with the rotation angle θ. This also applies to movement commands in the Y direction.

Note that after the θ correction described above, it is desirable to obtain the coordinates at two measurement points of the same probe needle again in the same manner as described above. If a θ deviation occurs in this result, the above θ correction is performed again based on the calculation result. By repeating this until the θ deviation is eliminated, the stage mechanism can be accurately moved in the Y direction in correspondence with the Y axis of the probe board. This also applies to the X axis.

Further, by accurately knowing the coordinates of the tip of the probe needle, the following functions can be added. That is, in the probe board, the probe needle is repeatedly pressed against the semiconductor chip on the semiconductor wafer to be measured every time the semiconductor chip is measured.

Therefore, the position of the tip of the probe needle shifts due to the stress caused by the repeated pressure bonding.

Therefore, in this embodiment, it is possible to determine whether or not the variation in the tip of each probe needle exceeds the allowable range by determining the distance from the tip of another probe needle using the tip of a certain probe needle as a reference. can. This makes it possible to add a new function of automatically determining whether to replace a defective probe board. By adding such a function, unnecessary tests of semiconductor wafers due to defective probe boards are not performed, so that the test time can be shortened. Furthermore, since the damage caused to the surface of the bonding pad by crimping the defective probe needle can be minimized, bondability in subsequent steps will not be deteriorated.

As a result, product yield can be improved.

Further, as described above, since the imaging device ITVI for photographing the tip of the probe needle is placed on the lower surface side of the probe board PB, a free space can be provided on the upper surface side thereof. This makes it possible to mount a large and heavy high frequency test head HFTH.

In addition, as shown by the dotted line in the same figure, the course alignment stage, in which the stage mechanism is moved and the probe board PB is not provided, has a dynamic An imaging device ITV2 is provided for aligning the axis and the Y axis and for needle alignment.

This imaging device ITV2 is attached so as to photograph the semiconductor wafer from the top side. The imaging device ITV2 sends the video signal to the pattern recognition device PT,
First, alignment is performed by performing pattern iFJ such as a scribe line on the semiconductor wafer. For example, by moving the stage mechanism in the dynamic axis X' direction corresponding to the X and Y axes of the probe board PB (probe needle array) and detecting the scribe line each time, the coordinates are located on the same coordinates. Adjust the θ of the measurement table as follows. After such alignment adjustment, the arrangement of the bonding pads of one semiconductor chip is recognized by the pattern recognition device PT. In this embodiment, the dynamic X' and Y' axes of the stage mechanism are aligned with the X and Y axes of the semiconductor wafer WF in accordance with the axes of the probe board PB. The arrangement of semiconductor chips and probe needles can be precisely aligned. That is, in this embodiment, the θ detection of the probe board PB, the θ adjustment of the semiconductor wafer, and
Highly accurate positioning is possible in which both the Y-axes are aligned substantially by position control by the stage mechanism. If a television camera is not mounted on the stage mechanism, errors between the X and Y axes of the television camera and the X and Y axes of the stage mechanism will directly appear as alignment errors.

For the θ adjustment of the probe hoard PB, the tip coordinates of a predetermined probe needle are determined. In addition, since the stage mechanism described above can control its position with high precision,
The position of the tip coordinate of the probe needle can be calculated from the amount of movement of the X/Y stage up to the course alignment stage. Therefore, automatic needle alignment is made possible by pattern recognition (coordinate recognition) of the bonding pads of the semiconductor chip in the course alignment stage.

In this way, when performing pattern recognition of semiconductor chip circuits and bonding pads in the course alignment stage, the probe needle is not included in the video signal, so
Compared to the conventional case where a semiconductor chip is imaged through an opening in a probe board, pattern recognition processing becomes easier because there is no need to remove the out-of-focus image of the probe needle as described above.

In addition, in the semiconductor wafer prober of this example,
By arranging the stage mechanism vertically, the control unit can be coupled in a vertical stacking manner to the stages 11 (X/Y) on which the wafer chuck is mounted. Therefore, when each unit is stacked as in this embodiment, the stroke in the Z direction is only 1 m to 30 m or less, so the width can be narrowed when it is vertical, and the stage mechanism can be As the size increases and functionality expands, the vertical dimension increases, making it possible to significantly reduce floor space. If the floor space can be reduced in this way, a large number of semiconductor wafer probers can be installed on a small floor, and it is also possible to perform parallel tests using a large number of semiconductor wafer probers.
As a result of being able to shorten the distance to the C tester (computer), the length of the signal transmission cable can be shortened, making high-speed testing easier.

In addition, when performing high-frequency tests, horizontally move the heavy high-frequency test head HFTH, which connects the high-frequency probes with spring properties to the electrodes of the probe board loaded on the semiconductor wafer prober. can be combined by Therefore, even if the high frequency test head HFTH is heavy, it can be easily coupled to the semiconductor wafer prober with a relatively small force.

FIG. 3 shows the probe board adapter into which the probe board PB is loaded and the high frequency test head HFTH.
A schematic cross-sectional view showing the connection with is shown.

The probe board PB is fixedly loaded by inserting a pin P electrically connected to a probe needle via printed wiring into a connector of a probe board adapter (board holder) PAD. The above probe board adapter PAD is the base BS of the semiconductor wafer prober.
It is fixedly attached to the by this,
The probe board PB is fixedly loaded in a non-rotatable state.

As described above, the probe board adapter PAD has a printed circuit board similar to the probe board PD, and the printed wiring PC electrically connected to the pins P is formed on the upper surface side of the printed circuit board. This printed wiring PC extends radially, and contact electrodes are formed on the outer periphery of the adapter PAD. As a result, it is possible to obtain electrodes that are arranged at relatively large intervals with respect to the connection pins of the probe board that are formed at high density. By widening the spacing between the electrodes, it is possible to arrange a large number of relatively large Pokopins with good transmission characteristics, as described below.

The high frequency test head HFTT (high frequency test head HFTT) is attached to the base via a support post HA, and a Bocobin PP corresponding to the electrode of the adapter PAD is provided. A transmission cable consisting of an internal coaxial cable etc. is connected from this Pokopin PP via a lead gL. A coaxial cable may also be used for the lead wire.

A guide hole for positioning is provided in the base of the high frequency test head HFTH on which the boko pin PP is provided. Corresponding to this guide hole, a guide pin CP for positioning is provided on the base BS of the semiconductor wafer blobber. As mentioned above, the adapter PAD is base B
Since it is fixedly attached to S, it becomes possible to accurately align the Boko pin PP and the electrode of the adapter PAD using the guide pin GP and the guide hole.

In this embodiment, by replacing the probe board PB loaded in the adapter PAD, measurement of semiconductor wafers can be easily performed on semiconductor wafers of different types, in other words, on which semiconductor chips with different electrode arrangements are formed.

As mentioned above, since the probe board is fixedly attached together with the adapter, compatibility with high-frequency test heads becomes easy. That is, since rotational adjustment for adjusting θ of the probe board PB is not necessary, the transmission path between the probe board PB and the high frequency test head can be made simple and short. This makes it possible to reduce transmission loss at high frequencies, thereby increasing the upper limit frequency that can be tested.

The effects obtained from the above examples are as follows.

<11 Detect the angle between the X or Y axis of the probe board and the X or Y axis of the stage mechanism on which the measurement stage holding the semiconductor wafer is mounted, and adjust the dynamic X axis of the test mechanism accordingly. By controlling the movement so that the and Y axes coincide with the X and Y axes of the probe board, the θ adjustment means of the probe board is no longer required, so the mechanism for mounting the probe board can be simplified. is obtained.

(2) With (1) above, there is no need to rotate the probe board, the connection path with the high frequency test head can be simplified, and highly reliable high frequency tests can be performed. The effect is that the upper limit frequency can be increased.

(3) As a means for detecting the angle of the probe board (probe needle), the probe needle is photographed from the side where the semiconductor wafer to be measured is placed on the X/Y stage mechanism that moves the measurement mounting table that suction-fixes the semiconductor wafer to be measured. By attaching an imaging device and detecting the above angle based on the video signal of this imaging device, a sharp video signal focused on the tip of the probe needle can be obtained, making it possible to accurately recognize the tip position. In addition, by moving the imaging device in the X or Y direction by moving the X/Y stage, an accurate θ shift can be determined from the detection of the same needle tip position.

This enables highly accurate θ detection of the probe board without being affected by the arrangement of the probe needles, so the dynamic X-axis and Y-axis of the stage mechanism can be adjusted to the X-axis and Y-axis of the probe board. The effect is that the precision can be matched.

(4) By installing an imaging device on the coarse alignment stage to recognize the pattern from the surface of the semiconductor wafer, dynamic alignment of the stage mechanism based on the X-axis or Y-axis can be performed. ,
This has the effect of automating needle alignment.

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 means for detecting the relative rotation angle between the X or Y axis of the probe board and the X or Y axis of the stage mechanism is to detect the tip of the probe needle from the opening of the probe board and the semiconductor located below. The rotation angle may be calculated by photographing the surface of the wafer using an imaging device and performing pattern recognition from the video signal. In this case, it can be configured with only one imaging device. However, in order to enable attachment of the high frequency test head as described above, the imaging device needs to be attached movably.

Furthermore, aligning the semiconductor wafer may be performed by aligning the true X-axis or Y-axis of the stage mechanism with the X-axis or Y-axis of the semiconductor wafer. In this case, when measuring the semiconductor chip, the stage mechanism is dynamically controlled to move along the X" and Y" axes in accordance with the axes of the probe board.In other words, after the alignment is completed, the stage mechanism is mounted for measurement. The table is rotated by the angle θ, and movement control is performed according to the dynamic X′ axis and Y° axis.

The X/Y stage mechanism constituting the semiconductor wafer prober is not limited to the above-mentioned vertical type, but may be of the horizontal type as in the past.

This invention can be widely used as a semiconductor wafer prober.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows. In other words, measurements that hold the semiconductor wafer with the X or Y axis of the probe board! 3! Detecting the angle with the X or Y axis of the stage mechanism on which the device is mounted, and matching the dynamic Y-axis and Y-axis of the stage mechanism with the Y-axis and Y-axis of the probe board accordingly. By controlling the movement in this manner, the probe board's θ adjustment means is no longer required, which simplifies the installation of the probe board, and also simplifies the connection path with the high-frequency test head, resulting in high reliability. High frequency testing can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of the main parts of the semiconductor wafer prober according to the present invention, FIG. 2 is a diagram for explaining a method for detecting θ deviation of the probe board, and FIG. 3 is a diagram showing the probe board and the high frequency FIG. 2 is a schematic cross-sectional view showing an example of a connection part with a test head. BS...Base, XS...X stage, YS...Y stage, Z...X stage, θ...θ stage, WF-...
Semiconductor wafer, ITVI, ITV2...imaging equipment, PT
・・Pattern recognition device, 5TGC・・Stage control device, PB・・Probe board, HFTH・・High frequency test head, PAD・・Probe board adapter, HA・
・Post, P...Pin, PC...Printed wiring, PP...
Bocopin, L...Lead wire, CP...Positioning guide pin

Claims (1)

[Scope of Claims] 1. An X or Y axis of a stage mechanism in which a probe board having a plurality of probe needles fixedly mounted thereon is mounted, and a measurement stage for holding a semiconductor wafer is mounted thereon. or a controller that controls the movement of the stage mechanism so as to match the dynamic X-axis and Y-axis of the stage mechanism with the X-axis and Y-axis of the probe board according to the relative angle with the Y-axis. Semiconductor wafer prober. 2. The angle is detected by an imaging device that is attached to the stage mechanism and that photographs the probe needle from the side where the semiconductor wafer to be measured is placed, and a pattern recognition device that receives the video signal formed by this imaging device. Claim 1, characterized in that the method is calculated from two-point coordinate information of a specific probe needle tip when the stage mechanism is moved by a certain distance in the X or Y direction using means. The semiconductor wafer prober described. 3. The semiconductor wafer prober according to claim 2, wherein the fixed probe board is fixedly attached to the high frequency test head.