JP2001050980A - Structure and manufacture of contact for electrode terminal of ic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure and manufacturing method for a fine contact which can get electrical connection, without scratching the electrode terminal of a wafer, bare chip, BGA, LGA, etc. SOLUTION: In a structure for contact, an organic elastic material 2 is enclosed inside a metallic film 3 formed on the surface of a metallic land 1b provided on a wiring board 1 and the material 2. Since the surface of the structure is composed of a metal having a low electrical resistance and the inside of the structure is soft, a contact that is apt to be deformed elastically can be manufactured. In addition, the film 3 and land 5 are formed integrally, and the strength of the contact also becomes higher.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a probe card or an IC socket used for performing an electrical characteristic test or a burn-in test by making an electrical connection to an electrode terminal of an IC wafer or a bare chip or an electrode terminal of an IC package during an IC manufacturing process. It concerns the child (contact).

[Prior art]

Conventionally, in order to remove a reliability defect occurring in an IC wafer manufacturing process, an IC is conventionally assembled and then removed.
A burn-in test in which a package is placed in an IC socket and energized in a heated state is performed. 2. Description of the Related Art In recent years, as electronic devices have become smaller and thinner, the need for bare chip mounting in which a bare IC chip is directly mounted on a substrate has been increasing.
On the other hand, there has been an increasing demand from semiconductor users who perform bare chip mounting to semiconductor manufacturers that they wish to perform a burn-in test in the wafer state or in a bare chip state cut into single chips and then ship only good chips. Have been. However, electrode terminals (bonding pads) of ICs in wafer or bare chip state
For example, the aluminum thin film and the solder bump are exposed, and are easily damaged by a small external force. Also,
The pitch of the electrode terminals is as fine as about 100 micrometers. There has been no effective method for obtaining good electrical contact without damaging these electrode terminals.

In addition, the number of electrode terminals of an IC tends to increase as electronic devices become faster and more sophisticated. In response to this trend, external electrode terminals of spherical solder bumps are provided on the lower part of the package in a grid. BGA (Ball
(Grid Array) package or LGA with flat pad-shaped external electrode terminals arranged under the package
(Land Grid Array) Although packages and the like are increasing, the pitch of the electrode terminals is becoming smaller year by year as the number of electrode terminals increases.

On the other hand, when performing a burn-in test or an electrical characteristic test, an electrical contact (contact) is pressed against an electrode terminal of an IC by a mechanical force, and is electrically coupled to the above-described test circuits. The basic requirements for this contact include long life and low electrical resistance.

[0005] In order to ensure the life of the contact, it is important that the breakage and breakage and other damages and wear are small. However, as described above, the pitch of the electrode terminals is becoming narrower, and the electrode terminals are fine and have high mechanical strength. The development of contacts was desired.

In general, it is natural to use a contact material having a low electric resistance in order to reduce the electric resistance of the contact. However, in order to reduce the contact resistance, a thin oxide film formed on the electrode terminal surface is required. Layers and contaminants must be removed. As this method, when the contact is pressed against the electrode terminal surface, it is known that it is effective to remove the oxide film and the contamination on the electrode terminal surface by elastically deforming the contact and sliding on the electrode terminal surface. . For this purpose, it has been desired to develop a contact which is elastic and can remove the oxide film and the contamination with a small force.

Conventionally, as a material of a contact electrically connected to an electrode terminal of the wafer, for example, Japanese Unexamined Patent Publication No.
A method of connecting a thin metal probe to an electrode terminal on a wafer as in the probe shown in FIG. 3 of 32226 is generally used. Therefore, it is almost impossible to make such thin pins contact all the electrode terminals on the wafer at once. Further, a thin metal pin not only easily damages the electrode terminals and bumps on the wafer, but also has a low mechanical strength, and thus easily deforms or breaks.

For this reason, FIG. 2 of JP-A-6-232226 is used.
As described in JP-A-5-340964, there has been proposed a method using a metal bump-shaped contact provided on a semiconductor substrate, a metal bump provided on a polyimide film shown in FIG. However, since the semiconductor substrate provided with metal bumps on the semiconductor substrate has low elasticity and is hardly deformed, when there is a manufacturing error of the contact or warpage of the wiring board, if all the contacts are to be electrically connected to all the electrode terminals. Also, there is a disadvantage that a large unbalanced load is applied to some of the electrode terminals and the electrode terminals are easily damaged. In the case of using the polyimide film, since the elasticity is large and easily deformed, the offset load can be reduced. However, since the metal contact is small in elasticity and hardly deformed, oxidation due to sliding of the contact on the surface of the electrode terminal is caused. Small effect of removing film and contamination.

The material of the contact electrically connected to the electrode terminal of the bare chip is, for example, a material which comes into contact with the bump-shaped electrode terminal, as shown in FIG.
As described, there is a planar contact provided on the interposer (substrate). However, since this contact is also low in elasticity and difficult to be deformed, as described above, the effect of removing the oxide film and the contamination is small, and the electrode terminal is damaged due to the uneven load. It has the disadvantage of being easy to do.

As a contact for electrically connecting to a BGA package having spherical electrode terminals, Japanese Patent Application Laid-Open No.
22, a metal pin embedded in a hole of a socket body, such as a pin terminal shown in FIG.
As shown in FIG. 2, there is a contact made of a conductive elastomer or the like embedded in a hole of a substrate. However, the metal pins have low elasticity and are not easily deformed, so that not only the electrode terminals are easily damaged, but also the mechanical strength is small, so that they are easily deformed and damaged.
Further, it is difficult to form a contact having a fine pitch of 1 mm or less. On the other hand, conductive elastomer contacts have the advantage that they are hard to damage electrode terminals because they are soft, but they generally have high contact resistance,
There is a disadvantage that the elastomer is easily worn because the elastomer is in direct contact with the metal electrode terminal.

The shape of the contact portion of the contact electrically connected to the BGA package includes a planar shape as shown in FIG. 1 of JP-A-7-273422 and a concave shape as shown in FIG. As described above, a metal contact having a planar shape has a small effect of removing an oxide film and contamination, and has a disadvantage that an electrode terminal is easily damaged by an uneven load. In addition, the metal-made concave shape has a disadvantage that when the corner portion strongly contacts the side surface of the spherical electrode terminal, the side surface of the electrode terminal is scraped and scratched.

[Problems to be solved by the invention]

As described above, the prior art is inadequate for making it possible to obtain an electrical connection with a small force and a small mechanical strength. The present invention relates to a contact corresponding to a fine and easily breakable electrode terminal, such as a wafer, a bare chip, a BGA, an LGA, etc., which is fine but has high elasticity and mechanical strength, and enables electrical connection with a small force. It is an object of the present invention to provide a contact structure and a manufacturing method thereof.

[Means for Solving the Problems]

The contact according to claim 1 is characterized in that an elastic organic material is sealed in a metal pattern (land) formed on a wiring board and in a metal film covering the surface of the organic material. Is what you do.

According to a second aspect of the present invention, there is provided a method of manufacturing a contact structure according to the first aspect, wherein after forming a projection made of an elastic organic material on a land on an upper surface of a wiring board, the land and the projection not covered by the projection are provided. A metal film is formed on both of the surface of the part, and the protrusions are completely sealed with the land and the metal film.

According to a third aspect of the present invention, there is provided the contact according to the first aspect, wherein a part of the metal film on the contact surface is removed.

A contact according to a fourth aspect is characterized in that the inside of the metal film has a hollow structure by melting and removing the elastic organic material inside the metal film from a portion where the metal film is removed in the contact according to the third aspect. It is.

The contact according to claim 5 is a contact according to claim 1,
The present invention relates to the shape of the structure of the contact according to the third and fourth aspects, wherein the central part thereof is concave.

[Action]

According to the present invention, a process for manufacturing a printed board, a ceramic substrate, a semiconductor, or the like can be used, and a contact having a fine structure can be efficiently manufactured.

The contact structure according to the present invention firstly comprises:
The function required for the metal film coated on the surface to ensure the electrical characteristics, that is, the function to remove the oxide film on the electrode terminal surface of the contact object such as wafer, bare chip, IC package, and the low electric resistance of metal Second,
The elastic organic material has the function of preventing damage to the electrode terminal surface because it is flexible and easily deformed even if there is a contact manufacturing error or warpage of the substrate. Third, the metal film is integrated with the land. High mechanical strength.

The contact according to the present invention can be designed in a complicated shape by using a manufacturing process for manufacturing a printed circuit board, a ceramic substrate, a semiconductor, and the like. Tall structures can be easily made.

Therefore, according to the present invention, it is possible to efficiently manufacture a contact which is fine but has high mechanical strength and can obtain an electrical connection with a small pressing force.

【Example】

FIG. 1 shows a basic structure of a contact according to the first aspect. The wiring board 1 includes a wiring board 1a made of an insulating material, a metal land 1b formed on the upper surface of the wiring board 1a, a through hole 1c formed in the wiring board 1a, and wiring 1d. The elastic organic material 2 is formed on the upper surface of the land 1b. A metal film 3 is coated on the surface of the elastic organic material 2 by plating, sputtering, evaporation, or the like.
Electrical contact is made by pressing against an electrode terminal such as a C package. The metal film 3 is joined to the upper surface of the land 1b all around the lower part of the elastic organic material 2. The material of the metal film 3 is preferably the same as that of the land 1b, but is not necessarily the same. The surface of the metal film 3 is often used as a contact material, for example, Au-based, p-type.
You may perform t-type or Pd-type plating processing.
According to this structure, since the metal film 3 is directly connected to the land 1b, the electric resistance is small, and since the metal film 3 is integrated with the land 1b, the structure is strong. Further, in this structure, since the elastic organic material 2 is filled in the metal film 3, a soft contact which has a metal surface but is easily elastically deformed can be realized. FIG. 1 shows one embodiment, and contacts of various shapes can be formed by changing the shape of the elastic organic material 2.

FIG. 2 relates to claim 2 and shows an example of a manufacturing process of the contact according to claim 1. FIG. 2A shows a state in which the elastic organic material 2 is applied or stuck on the entire surface of the wiring board 1. FIG. 2B shows a state where the elastic organic material 2 is processed into a predetermined shape. The processing may use a general photolithography step or a removal processing using a laser beam. FIG. 2C shows a state in which the surface of the elastic organic material 2 is selectively coated with the metal film 3. As a method of selectively covering the metal film 3 as described above, a method of performing electroplating using the elastic organic material 2 as a conductive organic material,
It is known that a method in which a catalyst for electroless plating is contained in the elastic organic material 2 to perform electroless plating is effective. After the film is formed on the entire surface, the metal film other than the contact portion may be removed by using a photolithography process.

FIG. 3 shows an example of the basic structure of the contact according to the third aspect. 3A and 3B show a case where a part of the metal film 3 of claim 1 is removed, FIG. 3A shows an example in which both side surfaces of the contact are removed, and FIG. Here is an example. Since this structure does not cover the entire surface of the metal film 3, it is easier to be elastically deformed than the contact structure according to the first aspect.

FIG. 4 shows an example of the basic structure of the contact according to the fourth aspect, wherein the elastic organic material 2 is removed from the structure of the contact according to the third aspect to form a hollow structure. FIG. 4A is FIG.
FIG. 4B shows an example in which the elastic organic material 2 is melted and removed from the structure shown in FIG. 3A to form the metal film 3 into an arc shape. Is melted and the metal film 3 has a cantilever structure. To make this structure, the elastic organic material 2 is applied to the wiring board 1a and the land 1
The material may be different from the material b and the metal film 3, and only the elastic organic material 2 may be immersed in a chemical solution that can be removed by melting. Also,
When the elastic organic material 2 is used as a photoresist material, the photoresist material may be melted in a developer.

FIGS. 5 and 6 show an application example of the contact shape of claim 5. FIG. 5 shows an example of a bump shape or a contact state with a spherical electrode terminal of a BGA. A contact having a concave central portion is in contact with the spherical electrode terminal 5 formed on the lower surface of the IC package body 4. Although FIG. 5 shows an example in which the present invention is applied to a BGA, the same shape can be applied to a contact for a bump-shaped electrode terminal of a wafer or a bare chip. FIG. 6 shows an example of a contact having a concave central portion effective for a spherical electrode terminal or a bump-shaped electrode terminal. FIG. 6 (A)
Is a contact corresponding to claim 1, FIG. 6B is a contact corresponding to claim 3, and FIG. 6C is an example in which the contact is divided.

FIG. 7 shows an example of a state in which a contact is brought into contact with a planar electrode terminal 7 formed on a wafer or bare chip substrate or the LGA package body 6. FIG.
The contact structure shown in FIG. 4 has a cantilever structure according to claim 4 and corresponds to a fine probe pin.
However, the present invention is not necessarily limited to the structure of claim 4, but may be the structure of claim 1 or claim 3.

FIG. 8 shows a modification of the first and second aspects of the present invention. An elastic ball 8 having a metal film 8b coated on the surface of a plastic ball 8a is bonded to a land 1b by bonding or welding, and the surface of the elastic ball 8 and the land 1b is coated with a metal film 2.

【The invention's effect】

As described above, according to the present invention, a wafer,
For fine and fragile electrode terminals such as bare chips, BGA, LGA, etc., it is possible to realize contacts that are fine but have high mechanical strength and enable electrical connection with a small force. It is possible to easily realize a probe substrate for a burn-in test in a wafer state in which contacts are collectively brought into contact with electrode terminals, a bare chip, and an IC socket for BGA or LGA. In addition, since a manufacturing process of a printed circuit board, a ceramic substrate, a semiconductor, or the like is used, mass productivity is achieved, and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 shows a basic structure of a contact according to the first embodiment.

FIG. 2 is an example of a manufacturing process of a contact according to claim 2;

FIG. 3 shows a basic structure of a contact according to claim 3;

FIG. 4 shows a basic structure of a contact according to claim 4;

FIG. 5 is a contact state diagram with a bump-shaped electrode terminal or a spherical electrode terminal of a BGA.

FIG. 6 is a structural example of a contact having a concave central portion.

FIG. 7 is a contact state diagram of contacts with planar electrode terminals such as a wafer, a bare chip, and an LGA.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Wiring board 1a Wiring board 1b Land 1c Through hole 1d wiring 2 Elastic organic material 3 Metal film 4 IC package main body 5 Spherical electrode terminal 6 Wafer, bare chip substrate or LGA package main body 7 Planar electrode terminal 8 Elastic sphere 8a Plastic sphere 8b Metal film 9 Joint

[Procedure amendment]

[Submission date] October 12, 1999 (1999.10.
12)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 shows a basic structure of a contact according to the first embodiment.

FIG. 2 is an example of a manufacturing process of a contact according to claim 2;

FIG. 3 shows a basic structure of a contact according to claim 3;

FIG. 4 shows a basic structure of a contact according to claim 4;

FIG. 5 is a contact state diagram with a bump-shaped electrode terminal or a spherical electrode terminal of a BGA.

FIG. 6 is a structural example of a contact having a concave central portion.

FIG. 7 is a contact state diagram of contacts with planar electrode terminals such as a wafer, a bare chip, and an LGA.

FIG. 8 is a structural example of a contact using an elastic ball.

[Description of Signs] 1 Wiring board 1a Wiring board 1b Land 1c Through hole 1d Wiring 2 Elastic organic material 3 Metal film 4 IC package main body 5 Spherical electrode terminal 6 Wafer, bare chip substrate or LGA package main body 7 Planar electrode terminal 8 Elasticity Sphere 8a Plastic sphere 8b Metal film 9 Joint

Claims (5)

[Claims] A contact for electrically connecting to a spherical or planar electrode terminal of an IC package or a bump or planar electrode terminal of an IC wafer or a bare chip, an elastic organic material is formed on a metal substrate on a wiring substrate. And a metal film coated on the elastic organic material. 2. The method according to claim 1, further comprising: forming a protrusion of the elastic organic material on the land formed on the wiring board; forming a metal film on the protrusion and the land; 2. The method of manufacturing a contact according to claim 1, wherein the metal film is sealed inside. 3. A structure of a contact according to claim 1, wherein a part of the metal film formed on the surface of the contact is removed. 4. The contact structure according to claim 3, wherein the inside of the metal film has a hollow structure by melting and removing the organic material from a portion where the metal film has been removed. Its manufacturing method. 5. The contact structure according to claim 1, wherein a central portion of the contact has a concave shape.