JPS5832782B2 - Fixed probe board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixed probe board used for inspection and measurement of semiconductor devices completed on a semiconductor wafer.

BACKGROUND OF THE INVENTION Conventionally, in the extremely wide variety of semiconductor manufacturing processes such as monolithic semiconductor integrated circuits, the blobbing process has tended to exist as an intermediate inspection.

However, when the entire process is roughly divided into the process up to the masked wafer and the process from there to the finished product, the blobbing process is the final check process that is comparable to a sea urchin fly, and it has a significant impact on labor saving 5 rationalization in the subsequent process. Rather than being large, it is a very important position.

In other words, as it has become possible to significantly reduce the defectiveness rate in the post-processes up to the finished product through automation, etc., the accuracy of the checks in the blobbing process has a large impact on product yield. It is from.

Fixed probes and
For example, on page 145 of Electronic Materials (November Extra Issue) published by IT on May 5, 1971, as ``Use of Fixed Probe Cards''
The one disclosed in Japanese Patent No. 354 is known.

This fixed probe board is intended to solve the problem of poor workability for mass-produced products such as adjustment and maintenance of adjustable multi-point blowers, as shown in the above "Electronic Materials."

Its usefulness has been shown.

The details of its structure are disclosed in Japanese Patent Publication No. 54-43354.

This fixed probe board (test probe assembly)
As shown in the main part plan view of FIG. 1 and the cross-sectional view of FIG. 2, probe needles 2 are fixed to a printed circuit board 1 using a support 4 and a fixing layer 5 in a conical radial shape.

However, the shape of the semiconductor chip, which is the object to be measured, is rectangular (square or rectangular), and it is inevitable that the tips 3 of the probe needles be arranged in correspondence with the electrodes (ponding pads) provided on the same side of the semiconductor chip. As mentioned above, it forms a rectangle.

When the probe needles are fixed in a conical radial shape with a specific acute angle with respect to the surface of the printed circuit board, the length of the probe needles from the fixed part to the tip will be different, and the distance of the tip in the vertical direction with respect to the surface of the printed circuit board. will be different.

In other words, let the above specific acute angle be θ, and the difference in length be △
The vertical difference △h when e is △h - △6sin
It is calculated by θ, and when θ is 9°, △IJ 73
Δh changes by 78 μ for each difference in 3 Q and 5 m'R.

Incidentally, there is a difference of 3.times.3.mu. (.DELTA.h) between probe needles of length l=4 and l=6 mm.

The method for assembling the probe board includes using an assembly jig that forms the conical radiation array and has an alignment mask in which a small hole corresponding to the measurement electrode is formed in the center, and the tip of the probe needle is masked. After arranging the probe needles while inserting them into the small holes and fixing the probe needles to the support,
It is attached to a printed circuit board.

The tip of the fixed probe needle has variations in the vertical direction as described above, and the flatness of the tip (dispersion in the plane formed by the tip) is within ±25 μm by manual inspection by visual observation. The disadvantage is that it requires adjustment.

Note that the tip of the probe needle is bent in a substantially vertical direction, so even if there is variation in the vertical direction of the bent portion, the variation can be corrected by adjusting the length from the bent portion to the tip. It is possible to correct it, but
In order to form many types of probe needles, each having a slightly different length from the bent portion to the tip, it is necessary to arrange the probe needles with selection, which is impractical.

Also, even if the tip of the probe needle is aligned to the flatness specified by the above adjustment work.

Due to the difference in the length of the probe needle from the fixed part to the tip, variations occur in the needle pressure when crimping the probe needle to the electrode of the object to be measured.

This variation in stylus pressure means variation in the stress on the probe needle, which causes variation in the flatness of the tip due to different residual strains, which shortens the time period in which flatness needs to be readjusted, reducing durability. The problem is that it lacks sex.

Furthermore, as mentioned above, variations in the flatness of the tips and variations in the probe needle length due to differences in the length of the probe needles cause the crystal structure of the wafer chip to change due to uneven pressure, which changes the semiconductor device characteristics. It has been found that since it has a piezo effect, it has the various drawbacks mentioned above, such as having an adverse effect on the wafer chip that is the object to be measured and causing the problem that the reliability of the test results cannot be maintained.

This invention was made to solve the above problems and to provide a new fixed probe board.

According to the basic features of the invention, the fixed end is electrically conductively fixed to the mounting piece that does not have spring properties with respect to the needle pressure cover and is made of a conductive member, and the tip is positioned in the substantially axial direction of the mounting piece. A plurality of probe needles are used on the fixed probe board, each having a needle extending from the other end and bent to face the measurement electrode.

Hereinafter, this invention will be described in detail along with embodiments.

FIG. 3a shows a side view of an example of the probe needle according to the present invention, and FIG. 3 shows a top view thereof.

A probe needle is composed of a mounting piece 10 made of a conductive thin plate and a needle 2'.

The mounting piece 10 is made of, for example, a thin iron plate or a copper plate, and although not particularly limited, its surface is plated with a highly conductive metal.

The mounting piece 10 has a side A that contacts (opposes) the surface of the wiring board when it is mounted on the wiring board.

On the other hand, the side C opposite to this side A is formed with a specific acute angle so as to widen in the direction in which the needle 2' is attached.

Further, a notch B is provided at the needle attachment end of side C to define the length of the fixed portion of the needle 2'.

f) S, the fixed end of the needle 2' is in contact with the thickness of the notch B of the mounting piece 10 and is fixed with an electrical connection by, for example, solder.

During this fixation, the tip 3, which is the free end of the probe needle 2', is bent so as to be parallel to the surface of the mounting piece 10.

In the probe needle configured as described above, when needles of the same length are attached to attachment pieces of the same shape as described above, the length L2 from the attachment piece part a to the tip, which is the length of the free end of the needle, and the side A
The vertical length Ll is the same for all probe needles.

This length Ll is the same for all probe needles by setting it perpendicular to the surface of the mounting piece 10 with the side A in contact with the probe needle mounting surface of the wiring board, as described later. The flatness of the surface formed by the tip of the probe needle can be made extremely high.

When the probe needles are fixed to the wiring board in the above state, by using the attachment piece 10, the free end length L2 of the needles 2' can be made constant among all the probe needles.

Although not particularly limited, the thickness of the mounting piece 10 is 0.
It is about 251 m, and the length of the 5 sides A is g, about 5 mm.

Such a mounting piece 10 is formed with highly accurate dimensions, for example, by selectively etching a thin plate of the above thickness using a photoresist film.

FIG. 4 shows a plan view of an embodiment of the fixed probe board according to the present invention.

In this embodiment, the probe needle mounting surface side of the printed circuit board 1 is shown.

In a rectangular opening 9 provided in the center of the printed circuit board 1, the tips of the needles 2' of a large number of probe needles are arranged radially, each aligned with the electrode of the semiconductor chip that is the object to be measured. .

The other end of the attachment piece 10 of the probe needle is electrically connected to the connection end of the wiring pattern 6 of the board 1 by, for example, solder.

In addition, at a predetermined position of the mounting piece 10, the surfaces of each mounting piece are parallel to each other, and the surface formed by the side A of each mounting piece constitutes one plane. In other words, each mounting piece The printed circuit board 1 and each probe needle are integrally fixed by a ring-shaped fixing body 11 made of an insulating fixing material so that the surface thereof is perpendicular to the mounting surface of the printed circuit board 1.

In forming such a fixed probe board, although not particularly limited, the probe needles are first fixed together.

For example, it has an alignment mask in which a small hole corresponding to the measurement electrode is formed, - the side A of the mounting piece 10 of each probe needle is held in one plane, and the side surface of the mounting piece 10 with respect to this holding surface is The probe needles are arranged radially using a vertical assembly jig, and the fixed body 11 is formed with an insulating adhesive.

After this adhesive hardens, it adheres to the wiring board,
The connection end of the wiring pattern 6 and the other end of the mounting piece 10 are soldered with force 3.

A fixed probe board formed in this way:
The shape formed by the fixed end a of the needle 2' in each probe needle is as shown by the dotted line in the figure.

This shape is independent of the shape of the fixed body 11, and the measurement electrode (
The shape corresponds to the shape of the needle tip).

That is, as described above, needle 2 in the probe needle
' is formed such that the free end length L263 is constant.

FIG. 5 shows a cross-sectional view of the fixed probe board in the plane direction of the mounting piece 10.

The lower surface (probe needle mounting surface) of the substrate 1 is in contact with the side AfJ3 of the mounting piece 10, and is fixed to the substrate 1 with a fixing member 11 such that the surface of the mounting piece 10 is perpendicular to the lower surface.

A needle 2' and 3 are attached to the notch part of the mounting piece 10 facing the opening 9 side of the substrate 1, and the free end tip 3 of the needle 2' is connected to the measurement electrode surface (a surface parallel to the surface of the substrate 1).
It is bent to face the

Further, the other end of the mounting piece 10 is electrically connected to the connection end of the wiring pattern 6 of the board 1 by solder 7 or the like.

Further, FIG. 6 shows a cross-sectional view of the fixed body 11 in a direction perpendicular to the surface direction of the mounting piece 10.

From the figure, it will be understood that the surface of the mounting piece 10 is held perpendicularly to the lower surface of the substrate 1 by the fixed body 11.

It is also understood that the needle 2' is fixed to the thick part of the mounting piece 10. In the fixed probe board according to this embodiment described above, the needle 2' is fixed to the thick part of the mounting piece 10. The free end length L2 of 2' and the length Ll with respect to the mounting surface of the substrate can be made substantially the same regardless of the shape of the electrode pattern.

Therefore, unlike conventional fixed probe boards, the troublesome adjustment work by visual observation of setting the flatness of the tip within a predetermined range can be omitted, and moreover, the flatness can be improved.

Furthermore, since the length L2 from the fixed end a to the pointed end can be made the same for each needle 2', the needle pressure of each needle 2' can be made uniform, which prevents the piezo effect on the semiconductor chip and prevents the blowing process. The causes of defects can be prevented, and the reliability of the test results can be improved, and as a result, the manufacturing yield of semiconductor chips can be improved.

Furthermore, since the stress on each needle 2' becomes uniform, the residual strain at the free end of the needle 2' due to repeated crimping also occurs in the same way for each needle 2', so the change in the flatness of the needle tip becomes small. , durability can be improved.

Furthermore, since the free end length L2 of the needle 2' is constant, the amount of movement of the tip on the electrode surface due to the amount of biting when the needle 2' is crimped onto the electrode surface becomes uniform for each needle 2'. Therefore, alignment to the electrode becomes simple.

In other words, if the amount of movement of the point on the electrode surface differs depending on the amount of penetration of the needle 2', consideration must be given to the tips of all needles so that the tip does not come off the electrode part due to the amount of movement, and the amount of penetration must be This is because it is not possible to obtain a large value.

Further, the needle 2' is made of a material with relatively high electrical resistance, such as tungsten, in order to obtain good springiness.

In this embodiment, the probe needle is composed of the above-mentioned needle and a mounting piece, and the advantage is that by selecting a small electrical resistance of the mounting piece, the electrical resistance of the probe needle as a whole can be reduced f) 3 be.

Furthermore, since the mounting piece is plate-shaped, it can have a shielding effect to prevent signal crosstalk.

That is, in the cross-sectional view of FIG. 6, a shielding effect can be obtained by arranging dummy mounting pieces to which a predetermined bias voltage (for example, ground potential) is applied on the left and right sides of the probe needle through which the measurement signal flows.

Furthermore, regarding the mounting piece 10, the side C opposite to the side A is
By forming the probe needle to widen toward the attachment end of the needle 2', the probe needle can be easily replaced.

For example, when one of the needles 2' becomes defective and needs to be replaced, the soldering 7 can be removed, the fixing body 11 can be softened by heat, etc., and the probe needle can be pulled out in the direction of the needle tip. The tips can be aligned simply by inserting a new probe needle into the hole formed by pulling out the defective probe needle.

In other words, since the hole is tapered,
This is because a new probe needle insertion position is defined.

The present invention is not limited to the above-mentioned embodiments; for example, as shown in the cross-sectional view of FIG. However, the flatness of the tips may be maintained by attaching needles with different bent tips corresponding to these attachment pieces 10° and 10'.

In this case, as shown in the figure, the needle 2' can have a multilayer structure, making it possible, for example, to measure a semiconductor chip that has electrodes on the same side and in the center of the semiconductor chip. I can do it.

Even in this case, the flatness and free end length of the needles can be made substantially the same for all the needles as described above.

FIG. 8 shows a cross-sectional view of the fixed body 11 in a direction perpendicular to the surface direction of the mounting piece.

In this case, if the fixed end a of the needle is bent in the vertical direction with respect to the side surface of the attachment piece 10, the needles 2', 2' can be made to intersect.

Furthermore, the needle 2' may be attached to the side surface of the attachment piece 10.

The mounting piece 10 may be of any material as long as it does not have spring properties against needle crimping.

However, it is convenient to use a thin plate on which a large number of probe needles can be arranged.

Further, in the case of a thin plate, if two sides A and C are provided, these sides A and C define the height and length of the tip of the needle 2 relative to the mounting surface of the board 1.

Therefore, the two sides A may be composed of protrusions that touch or face the substrate 1 at at least two points,
The above-mentioned sides may be formed together with the fixed body.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the prior art, FIG. 2 is a sectional view thereof, FIG. 3a is a side view showing an embodiment of a probe needle according to the present invention, and FIG. Its top view,
FIG. 4 is a plan view showing an embodiment of the fixed probe board according to this invention, FIG. 5 is a sectional view thereof, and FIG.
A cross-sectional view in a direction perpendicular to the surface direction of the mounting piece,
FIG. 7 is a sectional view showing another embodiment of the present invention;
The figure is a sectional view taken in a direction perpendicular to the surface direction of the mounting piece. 1... Board, 2... Probe needle, 2'
, γ... Needle, 3... Tip, 4...
...Support, 5...Fixing layer, 6...Wiring means, 7...Solder, 8...Through hole, 9...・Opening, 10, 10'...
・Mounting piece, 11... Fixed body.

Claims (1)

[Claims] 1. Consisting of a printed circuit board with an opening in the center and a thin conductive metal plate, the printed circuit board is radially arranged such that its surface is perpendicular to the lower surface side around the opening of the printed circuit board. a plurality of mounting pieces arranged in the same manner as above, the other side facing the one side in contact with the lower surface of the printed circuit board at a specific acute angle that widens toward the opening, and the fixed end thereof on the other side of the mounting piece. A plurality of probe needles are connected to each other and extend linearly below the opening along the acute angle of the other side, and are aligned so that their tips face the measurement electrodes on the semiconductor wafer to be measured; A fixed probe board comprising an insulating fixing body fixed to the lower surface of the printed circuit board, and mounting pieces fixed to each other underneath. 2. The fixed probe board according to claim 1, wherein the mounting piece and the probe needle have the same shape and size, and are mounted in the same manner. 3. The fixed probe according to claim 1 or 2, wherein the fixed body is configured so that the attachment of the attachment piece and the probe needle is reinforced. ·board.