JPH0384470A - Semifixed probe board - Google Patents

Abstract

PURPOSE:To make secure connections by forming probes on flexible film bases corresponding to electrodes on the respective sides of an LSI and allowing the tip parts to move vertically when contacting the electrodes. CONSTITUTION:When there are measurement electrodes on the four sides of the LSI, four flexible flat cables FPC1 - FPC4 are constituted separately from one another corresponding to the electrodes. Then a support is provided so as to support the probes consisting of the flat cables. Then the entire shape is wedgelike and the support is provided between the board and cables FPC1 and FPC3, etc., so that the tips of the FPC1 and FPC3 face down at a constant angle. Then manipulators 1 and 3, etc., are fitted as positioning means for positioning the tip end part of the board in directions (x), (y), (z), and (theta). In this constitution, the probe tip parts move vertically when positioned and contacting the electrodes, and consequently the tips slide in the horizontal direction of a chip to come into excellent contact.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semi-fixed probe board, and relates to a technique that is effective when, for example, wiring formed on a flexible film is used as a probe. .

[Conventional technology]

Instead of the conventional probe board that uses thin wire probe needles made of tungsten, etc., this probe card uses photographic technology to form wiring with fine patterns on a flexible film base and uses it as a probe. is being developed. With this probe card,
Since it is possible to form signal lines that act as probes using photographic technology, it is possible to measure semiconductor integrated circuits with high-density electrodes that are impossible to measure using conventional probe needles made of thin filaments. become. Regarding such probe cards, for example, the magazine "Semiconductor International"
ERNATIONAL) J August 1988 issue, page 9
There are pages 8 to 101.

[Problem to be solved by the invention]

In the above-mentioned probe card, a wiring layer is formed on a conical integral film base having a bottom surface corresponding to a semiconductor chip. Therefore, the tip of the wiring that contacts the electrode of the semiconductor chip is completely fixed.

With this configuration, there is a problem that an oxide film is formed on the electrode made of the aluminum layer of the semiconductor, or it is not possible to penetrate the adhered dust, etc., and it is not possible to obtain a stable and good electrical contact. has. Also,
When the tip of the wiring that acts as a probe is integrally formed on the film base as described above, it becomes difficult to align the tip. In other words, although it is possible to accurately form fine patterns on a film base using photographic technology, the film base itself has thermal expansion properties, and it is difficult to accurately form wiring patterns on a flat film base. Even if the film base is processed into a conical shape, there is a risk that the film base will expand or contract. In addition, no consideration has been given to capacitive coupling of wiring layers that serve as signal transmission paths, and because wiring layers that serve as signal transmission paths are formed adjacent to each other at high density, mutual interference of signals may occur due to capacitive coupling, etc. However, there is a problem in that good signal transmission cannot be achieved for high frequency components.

An object of the present invention is to provide a semi-fixed probe board that can stably obtain good electrical contact.

Other objects of this invention include gigahertz, etc.

An object of the present invention is to provide a semi-fixed probe board that can obtain good signal transmission characteristics up to a high frequency band.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Means for Solving Problem C] A brief summary of typical inventions disclosed in this application is as follows.

That is, a wiring layer is formed on a flexible film, the tips of which are respectively formed in accordance with the measurement electrodes formed on one to four sides of the semiconductor integrated circuit to be measured, and the tips of the wirings are aligned vertically. A semi-fixed probe board corresponding to each side of the semiconductor chip is constructed by attaching the probe board to the board so as to be movable, and the board is attached to a manipulator for adjusting the position of the tip of the wiring. Further, a shield line is provided between the signal lines serving as the signal transmission path, or a microstrip line is formed.

[For production]

According to the above-mentioned means, probes are formed on flexible film bases corresponding to the electrodes provided on each side of the semiconductor integrated circuit, so that the probes can be manufactured easily and the probes can be easily manufactured when making contact with the electrodes. The tip moves vertically, and as a result, the tip slides horizontally over the electrodes of the semiconductor chip, breaking through the oxide film, dust, etc., and achieving a good electrical connection. Furthermore, since a good signal transmission path can be constructed using the shielded wire or the microstrip line, signal transmission up to a high frequency band such as gigahertz is possible.

〔Example〕

FIG. 1 shows a bottom view of an embodiment of a probe section constituting a semi-fixed probe board according to the present invention.

Using manufacturing technology such as flexible flat cables,
Using photographic technology on a flexible film base, the tips of the electrodes (ponding pads, etc.) provided on each side of the semiconductor integrated circuit (semiconductor chip) to be measured, which is charged and discharged on a semiconductor wafer, are measured. are aligned and wiring layers are formed radially. That is, the tip of the strip-shaped flat cable is tapered so as to have a side corresponding to one side of the semiconductor integrated circuit, and a radial wiring layer is formed thereon. The tip of this wiring layer, which corresponds to the electrode of the semiconductor integrated circuit, acts as a probe. That is, in the probe board of this embodiment, the probe and the signal transmission path are integrally constructed.

In addition, shield wires as shown by dotted lines in the figure are provided between these wires to ensure good signal transmission substantially similar to that of a coaxial cable. If the wiring layers are densely packed at the tip and there is insufficient space to form the shield line, a shield line is provided except for that area.

In this embodiment, when measurement electrodes are provided on each of the four sides of a semiconductor integrated circuit, four electrodes are provided corresponding to each side.
1 flexible flat cable FPC1 to FP
C4 is formed. These are configured separately from each other. Therefore, this is significantly different from the conventional method in which all the wirings acting as probes are formed integrally with respect to the electrodes of one semiconductor integrated circuit. For this reason, the probe board of this embodiment is a semi-fixed probe board. This is because the four flexible flat cables FPCI or FPC4 are formed with each wiring aligned only with the electrode of the corresponding semiconductor integrated circuit, and the mutual positional relationship between them is limited to that of the fixed probe board. This is because it is not structured in a fixed manner.

Therefore, as will be described later, when aligning to a semiconductor integrated circuit, all the probes are not aligned to the semiconductor chip integrally as in the past, but each probe is positioned individually for each flexible flat cable FPCI or FPC4. It is necessary to make adjustments.

When the four flexible flat cables FPCI to FPC4 are aligned with respect to one semiconductor integrated circuit by alignment means as described later, an opening is formed at a location corresponding to the semiconductor integrated circuit. That is, unlike the conventional blowbo card, the opening is not fixedly provided, but four flexible flat cables are attached as described above to form the opening for observing the needle tip. The shape and size of this opening match the shape of the semiconductor integrated circuit chip as described above.

Although not particularly limited, on the opposite surface of the film base in the figure, there is a tip grounding wire that is arranged to connect the tips of the shield wires and provides a ground potential through a through hole, and a tip grounding wire. A grounding line is provided to provide a grounding potential to the grounding line. In addition, the power supply line that supplies the power supply voltage and ground potential to the semiconductor integrated circuit is led to the vicinity of the opening by thick wiring on the opposite side of the film base, and from there is connected via a through hole to the wiring layer that acts as a probe. There may be. By doing so, the power source impedance can be reduced.

In this embodiment, although not particularly limited, the other end side of the film base may be extended so as to integrally form a flexible flat cable. That is, although the other end of each flexible flat cable FPCI to FPC4 is omitted in the figure, it is formed to have a relatively long length so as to extend as it is to the IC tester. Alternatively, it may be cut to the appropriate length and connected to the IC tester via another flat cable or coaxial cable. At this time, the impedance of the flat cable is set so as to match the impedance between the flexible flat cable and the coaxial cable, or a buffer amplifier for impedance matching is provided.

FIG. 2 shows a side view of one embodiment of a semi-fixed probe board according to the present invention.

The figure exemplarily shows two semi-fixed probe-holds arranged on the left and right in FIG. 1 as a representative. A support is provided to support the probe made of a flexible flat cable as described above. The overall shape of the support body is wedge-shaped, and the support body is connected to the board and flexible flat cable FP so that the tip of the flexible flat cable FPCI points downward at a certain angle.
C1. This also applies to the relationship between the flexible flat cable FPC3, which is exemplarily shown as another representative, and the support and the board. However, no support is provided up to the tip. This allows the leading end of the flexible film supported by the support to move freely up and down.

A spring member is provided to support this tip portion with a desired springiness in a plane along a constant angle with respect to the lower surface of the board.

This spring material is not particularly limited, but as shown in the figure, it is made of a thin temporary spring material, and the part where it is attached to the board has an inverted shape, and the part where it is connected to the flexible flat cable has the above-mentioned flexible flat spring material. The cable is shaped like an abbreviation so that it extends at the above-mentioned certain angle. and,
Although not particularly limited, the thickness of the leaf spring is reduced toward its tip to provide a desired contact pressure. Although not particularly limited, the tip of the signal line that acts as a probe is provided with an electrode similar to that of the known probe card. An opening is formed by the four boards, and the tip of the probe and the electrode of the semiconductor chip to be measured are enlarged from above using a microscope or an imaging device, making it possible to observe their alignment. In order to observe the tip of the probe, the flexible film base is made transparent or semi-transparent, and the position of the tip of the wiring layer serving as the probe can be observed from above through the opening using a microscope or an imaging device. be made into

As mentioned above, the board to which the flexible flat cables FPCI, FPC3, etc., which are designed as probes and cables, is attached has a manipulator 1. It is attached to the manipulator 3. These manipulators 1. The manipulator 3 is provided with adjustment screws for adjusting the position of its tip in the X direction, the Y direction, the X direction, and the θ direction. These manipulators are often used in conventional adjustable probers and the like, and can be constructed using the same or similar mechanism. Note that the boards corresponding to the flexible flat cables FPC2 and FPC4 shown in FIG. 1 are also attached to the same manipulators as described above, and the tips of their probes are aligned.

FIG. 3 shows a side view of another embodiment of a semi-fixed probe board according to the present invention.

When a temporary spring material is used as in the above embodiment to impart elasticity to a probe that uses a signal line formed on a flexible film, unevenness may occur on the plane formed by the electrodes of the semiconductor chip to be measured. The surface formed by the contact electrode surface at the tip of the probe is defined by the highest electrode, and there is a risk of poor contact or insufficient contact pressure with respect to the lowest electrode. Therefore, in this embodiment, silicone rubber, for example, is used as the spring material.

That is, silicone rubber is provided so as to maintain the surface of the flexible flat cable formed by the support. Therefore, the tip of the board is configured to extend to a position corresponding to the tip of the flexible flat cables FPC1 and FPC3. Thereby, a resilient material such as silicone rubber is provided between the bottom side of the board and the top side of the film base on which the signal lines acting as probes are provided. In this configuration, the film base is supported flexibly by the elasticity of silicone rubber, etc., and the individual signal lines can be brought into contact with each other by absorbing the slight irregularities that exist on the electrodes of the semiconductor chip. . In addition, in order to avoid poor contact when using the above-mentioned plate springs, it is possible to make multiple cuts in the plate springs along the signal lines and convert the temporary springs into equivalent linear springs. The contact electrodes of the signal line may have different heights corresponding to variations in the flatness of the electrodes to be contacted.

FIG. 4 shows a schematic sectional view for explaining the concept of the contact operation of the probe board according to the present invention.

In the figure, A corresponds to the support opening,
B indicates its tip. Therefore, the tip B is made movable up and down with the above-mentioned point A as a fixed point. In addition, in the same figure,
The signal line as a probe and a flexible film base are depicted as an integral part.

When the contact end B of the probe starts contacting the electrode of the semiconductor chip IC, if the semiconductor chip IC is further pushed up by ΔZ in the vertical direction (Z up), the contact end B will also change to "B". As a result, the electrode of the semiconductor chip and the tip of the probe are electrically connected with a constant contact pressure.At this time, in response to the above Z-up operation, the tip of the probe B' is pushed up. The probe tip slides and moves forward on the electrode surface by ΔX (or ΔY).The semiconductor chip It is possible to break through the oxide film formed on the surface of the electrode and the adhering dust.Such a contact operation makes it possible to obtain stable and good electrical contact.

Therefore, as mentioned above, shielded wires are provided on both sides of the signal line that acts as a probe, which provides good signal transmission characteristics and provides high reliability up to high frequencies such as gigahertz (GHz). This makes it possible to perform AC tests (functional tests) on semiconductor integrated circuits.

Further, the present invention constitutes a probe using a flexible flat cable independently corresponding to each side on which electrodes of a semiconductor integrated circuit are formed, and a cable integrally constructed therewith. For this reason, when the tip of the probe is formed using photographic technology to accurately match the electrode of the semiconductor integrated circuit, it is only necessary to form the tip to match the electrode corresponding to one side, which simplifies the manufacturing process. That is, the manufacturing process can be significantly simplified compared to the conventional case in which all probes are integrally formed on one flexible film base.

The effects obtained from the above examples are as follows. That is, (1) forming a wiring layer on a flexible film, each having a tip end corresponding to each of the measurement electrodes formed on one to four sides of a semiconductor integrated circuit to be measured; are attached to the board so that they can be moved vertically to form a semi-fixed probe board corresponding to each side of the semiconductor chip, and the board is attached to a manipulator that adjusts the position of the tip of the wiring. Attach. In this configuration, probes are formed on flexible film bases corresponding to the electrodes provided on each side of the semiconductor integrated circuit, so manufacturing is easy and the tip of the probe is The tip moves in the vertical direction, and as a result, the tip slides horizontally on the electrode of the semiconductor chip, breaking through the oxide film, dirt, etc., and making a good electrical connection possible.

(2) By using silicone rubber as a spring material to impart springiness to the tip of the flexible film base, and by supporting the film base flexibly with its elasticity, the individual signal lines can be connected to the electrodes of the semiconductor chip to some extent. The effect is that unevenness can be absorbed and the two can be brought into contact.

(3) By providing a shielded wire between the signal lines serving as a signal transmission path, it is possible to construct a signal transmission path equivalently similar to a coaxial cable, making it possible to transmit signals up to high frequencies (GH2). Effects can be obtained.

(4) The above (1) or 3) act synergistically to produce a probe board that has high reliability and is capable of electrical measurements up to high frequencies (GHz). It will be done.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above-mentioned Examples, and it goes without saying that various changes can be made without departing from the gist thereof. Nor. For example, if the semiconductor integrated circuit to be measured is a dynamometer type RAM (Random Access Memory) where electrodes are provided only on opposite sides of the chip, two A probe board is constructed using the same flexible film base as described above.

At this time, the above two boards are attached to two manipulators. In addition, if there is enough wiring density,
The signal lines do not need to be in a radiating state as shown in FIG. If the characteristic impedance of the signal path cannot be made constant by increasing the distance between the signal line and the shielded line as the distance from the tip increases, the thickness of the shielded line should be made thicker toward the outer periphery, and the signal line The distance between the shield wire and the shield wire may be always constant. A flat cable can be used to temporarily hold the input signal to the semiconductor integrated circuit that is to be measured, temporarily hold the data output from the semiconductor integrated circuit, perform serial/parallel conversion of the signal, Alternatively, various semiconductor integrated circuit devices forming part of a tester for performing comparison with expected values may be mounted.

Means for connecting the wiring layer formed on the flexible film base as described above to the IC tester side include the method using the flat cable described above, as well as the method of connecting the wiring layer formed on the board with the connection provided on the board. Various embodiments can be adopted, such as a configuration in which the electrode is connected to the electrode using a pogo pin or the like.

Furthermore, the configuration of the signal line and probe is based on a known method in which a film base is used as a dielectric, a conductor is formed on one side of the base to serve as the wiring and a probe, and a conductor is formed on the entire other side. strip line (
strip 1ine) may also be used.

In such a microstrip line, at an extremely high frequency, a small amount of surface waves are induced on the substrate surface, and an electromagnetic field component exists in the traveling direction. For this reason, the signal propagating on the strip line is treated as a quasi-TEM wave (quasi-TEM wave).
iTEM) Often called waves.

When observing the probe tip and the surface of the semiconductor chip from the upper surface of the probe board, a method may be adopted in which the probe tip is observed from the lower surface of the probe board. That is, in a semiconductor wafer blower,
It is conceivable to observe the position of the tip using an image sensor from the bottom side of the probe board and automatically align the semiconductor chip based on the position information.

The configuration of the manipulator that aligns the tip of the probe provided corresponding to each side of the semiconductor integrated circuit on which the electrode is formed can take various embodiments. In addition to making X, Y, Z, and θ adjustments like a manipulator, similar adjustments are made when attaching each probe board, which is provided corresponding to each side of the semiconductor chip on which the electrodes are formed, to the blower. However, it may also be fixed. At this time, it is convenient to use an appropriate positioning jig, mark, etc.

The present invention can be widely used as a probe board used for measuring various small electronic components such as semiconductor integrated circuits.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows. That is, a wiring layer is formed on a flexible film, the tips of which are respectively formed in accordance with the measurement electrodes formed on one to four sides of the semiconductor integrated circuit to be measured, and the tips of the wirings are aligned vertically. One of the semiconductor chips is attached to the board so that it can be moved.
Constructs a semi-fixed probe board that corresponds to each side,
The position of the tip of the above wiring is gJ! Attach the above board to the manipulator to be adjusted. In this configuration, probes are formed on flexible film bases corresponding to the electrodes provided on each side of the semiconductor integrated circuit, so manufacturing is easy and the tip of the probe is The tip moves in the vertical direction, and as a result, the tip slides horizontally on the electrode of the semiconductor chip, breaking through the oxide film, dirt, etc., and making a good electrical connection possible. In addition, by providing a shielded wire between the signal lines as a signal transmission path or using a microstrip line, a signal transmission path equivalent to a coaxial cable can be constructed, so it is possible to construct a signal transmission path equivalent to a coaxial cable. It becomes possible to transmit signals up to high frequencies.

[Brief explanation of drawings]

FIG. 1 is a bottom view showing an embodiment of a semi-fixed probe board according to the present invention, FIG. 2 is a schematic side view showing an embodiment of a semi-fixed probe board according to the present invention, and FIG. FIG. 4 is a schematic side view showing another embodiment of the semi-fixed probe board according to the present invention. FIG. 4 is a schematic sectional view for explaining the concept of the contact operation of the semi-fixed probe board according to the present invention. FPCI~FPC4...Flexible flat cable (probe and signal line)

Claims (1)

[Scope of Claims] 1. A wiring layer including a wiring layer whose tip portions are respectively formed in accordance with measurement electrodes formed on one to four sides of a semiconductor integrated circuit to be measured on a flexible film,
The tips of the wires are attached to boards so that they can move vertically, and these boards can be fixed to the prober by adjusting the positions of the tips of the wires, or the boards can be attached to the prober by adjusting the positions of the tips of the wires. A semi-fixed probe board characterized in that it is attached to a manipulator. 2. In the vertically movable portion, a resilient spring material or silicone rubber is placed between the board and the opposite side of the surface on which the wiring layer is provided so that the tip part has resilience. A semi-fixed probe board according to claim 1, characterized in that it is provided with a semi-fixed probe board. 3. The above-mentioned wiring layer is provided with a shielded wire to prevent interference of signals between the wirings or is made into a microstrip line, and the other end side extends as it is and is connected to a tester. Claim 1st or 2nd
Semi-rigid probe board as described in section.