JP2000180472A - Probe board for bare chip inspection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe substrate for inspecting bare chips simultaneously provided with electrode alignment performance and oxide film breaking performance. SOLUTION: Parts 4 for forming electrodes are each formed at the tips of the wiring 3 of a wiring layer formed on a polyimide film 1, and an electrode 5 for checks constituted of a plurality of fan-shaped protrusion parts 6 obtained by dividing a circle by straight lines passing the center of the circle is formed on the part 4 for forming electrodes. As the electrode 5 comprises a plurality of fan-shaped protrusion parts 6 and can be regarded as a circular electrode as a whole, the electrode 5 comes into reliable contact with the electrode pad surface of a semiconductor chip. In addition, an individual fan-shaped protrusion part 6 comprises straight and circular edge parts, it is possible to break an oxide film on the electrode pad surface of a semiconductor chip reliably and to lower contact resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe substrate for bare chip inspection, and more particularly to a probe substrate for bare chip inspection capable of ensuring good electrical contact with semiconductor chips.

[0002]

2. Description of the Related Art A printed circuit board on which a plurality of unpackaged bare chips are mounted is mounted on an MCM (Multi C
(Hip Module). With the development of electronic devices, the MCM has come to be positioned as an important technique for device development as an effective means for meeting the essential needs of light and thin.

However, the biggest obstacle is a non-destructive inspection method for selecting a bare chip (KGD) of guaranteed quality. For this purpose, a check electrode is brought into contact with an electrode pad of a semiconductor chip. Thus, the point is to develop an inspection probe board for confirming electrical continuity.

As a conventional inspection probe substrate, a substrate having a needle of tungsten as a check electrode is often used. However, the size of the semiconductor chip is reduced and the number of pins is increased due to the increase in the number of pins. As the pitch becomes smaller, this type of probe board, which has a limit in miniaturization, cannot cope with it.

[0005] As a new type of probe substrate for inspection which replaces a substrate using a tungsten needle, a fine substrate utilizing a photo-etching technique and a micro-bump forming technique has been proposed.

A wiring layer of a predetermined pattern required as a probe substrate is formed on a resin film of polyimide or the like by photoetching, and a protrusion as a check electrode is formed at a predetermined position of the wiring layer. The probe board based on the fine wiring according to U.S. Pat.

In this probe substrate, the oxide film on the electrode pad surface of the semiconductor chip or the oxide film of the solder layer formed on the electrode pad can be destroyed by forming the projections small. Therefore, it is preferable that the protrusions constituting the check electrodes are formed as small as possible.

On the other hand, when quality inspection of a semiconductor chip is performed using a probe substrate, no special precision adjustment is performed for alignment with the electrode pad of the chip, and the bare chip side is usually inspected with an inspection jig. It is difficult to correctly match the electrodes of the bare chip with the electrodes for checking, since it is merely a rough alignment of dropping it into a certain socket, and it is common knowledge that a deviation of about several tens of micrometers occurs.

[0009] Therefore, to make the projection small,
This means that the bare chip electrode and the check electrode of the probe board are in a non-contact state, and there is a limit to miniaturization of the protrusion. For this reason, usually, priority is given to the alignment between the electrode of the chip and the electrode for checking, and the protruding portion of the probe substrate is usually made larger.

[0010]

However, according to such a conventional probe substrate, there is a case where the oxide film is not sufficiently destroyed by the projections, so that the contact resistance must be increased by the intervention of the oxide film. It may interfere with the performance of the test.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bare chip inspection probe substrate having both the alignment between electrodes and the destruction of an oxide film.

[0012]

In order to achieve the above object, the present invention provides an insulating substrate, a wiring pattern having a predetermined pattern formed on the substrate, and a predetermined portion of the wiring layer. In a bare chip inspection probe substrate composed of an electrode forming portion formed at the electrode forming portion and a checking electrode formed at the electrode forming portion and brought into contact with the electrode of the semiconductor chip, the checking electrode is a straight line passing through the center. A probe substrate for bare chip inspection is provided which is formed as a plurality of sector-shaped projections obtained by dividing a circle into a plurality of portions at the electrode forming locations.

As described above, the reason why the check electrode is constituted by the plurality of protrusions is to make each of the plurality of protrusions have destructive property against the oxide film. When comparing an electrode having a single configuration with an electrode having a plurality of configurations as in the present invention, the former is not divided because the size thereof cannot provide sufficient oxide film destructibility. Each of the projected portions can deal with the oxide film.

Therefore, when the size of the electrode is the same, the latter having a small projection shows higher oxide film destruction property. In addition, this configuration enables a large check electrode to be formed by an aggregate of a plurality of small protrusions, and also ensures the alignment of the electrodes.

The reason why the present invention forms the check electrode by a plurality of sector-shaped projections obtained by dividing a circle into a plurality of parts by a straight line passing through the center is that the projections are arranged neatly using the sector shape. This is to make the contact surface of the check electrode uniform.

In the case of a sector-shaped projection, a long edge that is vertically stood will break the oxide film longer, as compared with, for example, a point-shaped projection, so that a sufficient electrical conduction state is created. Can be. As the size of the projection,
One side should be set to 100 μm or less, and if it exceeds this, it becomes difficult to destroy the oxide film.

The projecting portion is often formed by nickel plating. For example, a surface palladium / base nickel, surface rhodium / base nickel, surface nickel alloy / base nickel, or a hard film such as diamond or silica and nickel are used. It may be formed by a combination of films.

As a constituent material of the substrate, for example, a fiber-reinforced synthetic resin such as an epoxy resin or a polyester resin reinforced with glass fibers, or a synthetic resin film such as a polyimide film or a polyester film is used.

When the substrate is made of a flexible material such as a resin film, it is advantageous for a test object having electrodes (for example, solder balls) having a variable height (about 50 μm) such as solder balls. The flexibility of the substrate allows for a flexible response to variations in the height of the electrodes of the product under inspection, thus preventing poor contact with the electrodes of the semiconductor chip and enabling high-precision quality confirmation Becomes

[0020]

Next, an embodiment of a probe substrate for bare chip inspection according to the present invention will be described. FIG.
Denotes a part of the probe substrate according to the present embodiment, 1 denotes a polyimide film, 2 denotes a wiring layer of a copper foil formed on the film 1 in a predetermined pattern, and 3 denotes a wiring of the wiring layer 2.

Reference numeral 4 denotes a circular electrode forming portion formed at the tip of the wiring 3 so as to match the position of the electrode pad of the bare chip to be inspected. The surface of the electrode forming portion 4 is formed of nickel plating. A check electrode 5 is formed by growth.

The check electrode 5 is composed of four fan-shaped protrusions 6 obtained by dividing a circle into a plurality of circles by a straight line passing through the center, and the surface of each protrusion 6 is in contact with an electrode pad of a bare chip. Gold plating is applied to reduce resistance. 2A, 2B, and 2C show examples of the shape of the protrusion 5.

FIG. 3A shows procedures A to J for manufacturing the probe substrate of FIG. Hereinafter, the contents of each procedure will be described. A: A laminate is prepared by laminating a copper foil of 18 μm thickness and a polyimide film 1 of 25 μm thickness with an adhesive of 12 μm thickness. B: A photoresist is applied on the copper foil side. C: A resist layer exposing a predetermined portion of the copper foil is formed by performing exposure and development of a predetermined pattern on the photoresist. D: The exposed portion of the copper foil is eluted by performing the etching, and the wiring layer 2 having a predetermined pattern having the electrode forming portion 4 at the tip of the wiring 3 is formed. E: The remaining resist layer is peeled off. FIG. 3B shows the product structure at this point. F: A photoresist layer is applied on the wiring layer 2 to a thickness of 20 μm. As the photoresist in this case, the use of a dry film resist is effective because the formed film thickness is relatively large. G: By exposing and developing the photoresist, a hole having a shape corresponding to the protrusion 6 is formed in the resist at the electrode forming portion 4. H: The whole is immersed in a nickel electrolytic solution, and nickel plating is grown at the electrode forming portion 4 in the hole of the resist, thereby filling the hole of the resist. I: The remaining resist is removed. J: immersed in a nickel plating solution, nickel-plated about 1 μm in thickness on the entire surface of the wiring 3, the electrode forming portion 4, and the projection 6, and then immersed in a cyan-based plating solution to obtain nickel plating. A gold plating having a thickness of about 0.3 μm is applied thereon. Observation of the probe substrate obtained above,
The edge of each projection 6 has a vertical edge, and it has been confirmed that the projection 6 has a destructive function effective against an oxide film.

[0024]

As described above, according to the probe substrate for bare chip inspection according to the present invention, since it has a plurality of fan-shaped protrusions, it can be regarded as one circular electrode as a whole, and thus the semiconductor chip Contact the electrode pad surface of the In addition, since each fan-shaped projection has straight and arc-shaped edges, the oxide film on the electrode pad surface of the semiconductor chip can be reliably broken to reduce the contact resistance.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a bare chip inspection probe substrate according to the present invention.

FIG. 2 is an explanatory view showing the shapes of three types of protrusions (a), (b), and (C) of a probe substrate for bare chip inspection according to the present invention.

3A and 3B are explanatory diagrams showing a method of manufacturing the probe substrate of FIG. 1, wherein FIG. 3A is a flowchart of a manufacturing procedure, and FIG. 3B shows a product structure during manufacturing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyimide film 2 Wiring layer 3 Wiring 4 Electrode formation place 5 Check electrode 6 Projection

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G003 AA00 AG03 AG12 2G011 AA16 AA21 AB06 AB07 AB08 AC14 AE03 4M106 AA02 BA01 DD01

Claims (3)

[Claims] An insulating substrate, a wiring layer having a predetermined pattern formed on the substrate, an electrode forming portion formed at a predetermined portion of the wiring layer, and an electrode forming portion formed at the electrode forming portion. A bare chip inspection probe substrate comprising a check electrode that is brought into contact with an electrode of a semiconductor chip, wherein the check electrode is formed as a plurality of sector-shaped protrusions obtained by dividing a circle into a plurality of circles by a straight line passing through the center. A probe substrate for bare chip inspection, wherein the probe substrate is formed at a location. 2. The bare chip inspection probe board according to claim 1, wherein each of the plurality of protrusions has a side length of 100 μm or less. 3. The probe substrate according to claim 1, wherein said substrate is made of a flexible material.