JPH09196969A - Probe structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe structure attaining a good contact with even an object the probe is brought into contact and of which hardness is 200Hk or below, and also whose surface is usually covered with an oxide film of a large electric resistance. SOLUTION: A conductive circuit 2 is provided on one surface of an insulation substrate 1, and at its end part, a contact point 3, surrounded with dashed line in the figure, is provided, and the contact point 3 consists of a basic shape part 3a and multiple fine projections 3b formed on its surface. A part 6 with which the probe is brought into contact formed on a to-be-inspected object 5 is made from a conductor of hardness 200Hk or below, and a solder ball, as one example, usually contains an oxide film 7 on the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe structure for conducting a continuity test, a function test or the like on a minute inspection object such as a semiconductor device.

[0002]

2. Description of the Related Art As a probe structure used for a continuity test of a minute semiconductor device such as an LSI, a surface having a large number of minute contacts on a plane to electrically contact an arbitrary measuring point on an integrated circuit. A membrane-shaped probe structure (hereinafter, simply referred to as a "probe structure") is known.

In recent years, solder balls or bumps are generally formed on the contact target portion of the semiconductor device which is the inspection target of the probe structure.

When the contact target portion is a solder ball or bump having a hardness of 200 Hk or less and the surface thereof is normally covered with an oxide film having a high electric resistance, the contact resistance is lower. As a method of contacting the contact portion, a method of reflow soldering a part of a solder ball or a bump to the contact portion (Japanese Patent Laid-Open No. 5-5087).
36), the entire contact portion is in the form of a pin, which allows the oxide film to be pierced and brought into contact with it, a solder ball or a bump that is sufficiently crimped to the contact portion to make contact, and a dendrite having a height of 10 μm to 100 μm Using a contact portion having a contact, the dendrite breaks through the oxide film and makes contact (Japanese Patent Laid-Open No. 6-252222).
6).

[0005]

However, in the above, there is a problem that the re-reflow is necessary because the amount of solder is changed, and the solder ball is also deformed in the above-mentioned re-reflow as well. Is a problem in that it is necessary.

Among the above methods, the method of contacting with is a method in which the oxide film on the surface of the contact target portion is pierced to make good contact with the unoxidized portion of the deep layer. However, the above method has a problem that the inspection becomes difficult when the contact target portions are arranged at a narrow pitch because the wiring pitch of the pins is limited. Further, in the above method, since the height of the dendrite is 10 μm to 100 μm, there is a problem that a cavity is generated in the contact target portion where the dendrite is stabbed and the reliability of the inspection object is lowered.

The object of the present invention is to solve the above-mentioned problems, and even if the hardness of the contacted portion is 200 Hk or less and the surface thereof is usually covered with an oxide film having a high electric resistance, The object is to provide a probe structure that can make good contact.

[0008]

The probe structure of the present invention has the following features. (1) A probe structure in which a conductor having a surface hardness of 200 Hk or less is to be contacted, and a contact portion provided on one surface of an insulating substrate and provided on either surface or inside of the insulating substrate. The contact portion is composed of a basic shape portion and one or more minute protrusions formed on the surface of the basic shape portion. Is 0.1 μm to 9 μm.

(2) The probe structure according to the above (1), wherein the hardness of the surface of the minute protrusion of the contact portion is 300 Hk to 1200 Hk.

(3) The probe structure according to (1) or (2) above, wherein the conductor to be contacted with the probe structure has a surface covered with an oxide film.

(4) The probe structure according to the above (1) to (3), wherein the conductor to be contacted by the probe structure is a metal ball or a metal bump.

(5) The minute protrusions of the contact portion are formed by depositing by electroless plating, and are formed so as to protrude from the surface of the basic shape portion (1) to (4). The probe structure described.

(6) The minute protrusions of the contact portion are formed by electrolytic plating using the conductive circuit as a negative electrode, and are formed by protruding from the surface of the basic shape portion. )-(4) probe structure.

(7) The entire contact portion including the minute protrusions is laminated in a plurality of layers so that the hardness of the surface is at least 300 Hk to 1200 Hk.
(6) The probe structure according to the above.

[0015]

By contacting a conductor having a hardness of 200 Hk or less, which is a contact target portion, with a contact portion having a fine protrusion having a height of 0.1 μm to 9 μm on the surface, even if an oxide film is present on the surface, Good contact with the unoxidized part of the deep layer. Also, when breaking through the oxide film with minute protrusions,
The contact target portion is not greatly recessed, and unlike the conventional recess formed by the dendrite, the reliability of the product to be inspected is not adversely affected.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view schematically showing an example of a probe structure according to the present invention. In FIG. 1, hatching of the cross section is omitted. In the probe structure shown in the figure, a conductive circuit 2 is provided on one surface of an insulating substrate 1, and a contact portion 3 surrounded by a dashed line in the figure is provided at an end portion thereof. The contact portion 3 is composed of a basic shape portion 3a and a plurality of minute protrusions 3b formed on the surface thereof. The inspection object 5 to be contacted is a semiconductor element,
The contact target portion 6 formed on the inspection object 5 has a hardness of 200H.
A solder ball, which is made of conductors of k or less, is shown as an example in the figure. The solder ball usually has an oxide film 7 on its surface.

FIG. 2 is a sectional view schematically showing another embodiment of the probe structure of the present invention. In FIG. 2, hatching of the cross section is omitted. In FIG. 2A, the contact portion 3 is provided on one surface of the insulating substrate 1 and the conductive circuit 2 is provided on the other surface, and the contact portion 3 and the conductive circuit 2 are insulated from each other. In the example shown in FIG. 1, those located on the front and back sides of the conductive substrate are electrically connected to each other through the conductive paths 4 formed in the insulating substrate 1. The contact portion 3 includes a basic shape portion 3a and a plurality of minute protrusions 3 formed on the surface thereof.
b. FIG. 2B shows an example in which the conductive circuit 2 is provided inside the insulating substrate 1 and the alignment sheet 8 for the semiconductor element, which is the inspection object 5, is formed on the insulating substrate. The contact portion 3 and the conductive circuit 2 are electrically connected to each other through a conduction path 4, and the contact portion 3 includes a basic shape portion 3a and a plurality of minute protrusions 3b formed on the surface thereof. The basic shape portion 3a is formed at the same height as the insulating substrate 1.
FIG. 2C shows an example in which a low expansion support substrate 9 is provided on one surface of the insulating substrate 1.

FIG. 3 is a sectional view schematically showing another embodiment of the probe structure of the present invention. In FIG. 3, hatching of the cross section is omitted. FIG. 3 (a)
In this example, the conductive circuit 2 is multi-layered and the inspection object 5 is a semiconductor wafer. FIG. 3B shows an example in which the external connection pin 10 is wired from the conductive circuit 2. FIG. 3C shows an example in which the inspection object 5 is a semiconductor element mounting substrate.

Examples of the object to be contacted with the probe structure include minute semiconductor devices such as LSI. The material of the contact target portion formed on the inspection object has a hardness of 20.
It is not particularly limited as long as it is a conductor of 0 Hk or less, and examples thereof include solder, gold, platinum, silver, indium, aluminum, tin and lead. Metal balls or metal bumps are often used as the contact target portion. Among them, solder balls or bumps as shown in FIG. 1 are generally used. Solder balls usually have an oxide film with a large electric resistance on the surface and have a hardness of 200H.
Since it is a conductor contact of k or less, it is necessary to break through the oxide film in order to obtain a good contact with the contact portion, and since it is a soft metal, it is easily dented or deformed by the contact pressure. The probe structure of the present invention has a height of 0.1 μm
The contact portion having the fine protrusions of 9 μm easily breaks through the oxide film and can make contact without greatly recessing the solder ball or bump, which is particularly useful when the solder ball or bump is the contact target portion.

The material of the insulating substrate is not particularly limited as long as it has an insulating property, but a material having an insulating property and flexibility is preferable. For example,
Thermosetting resin or thermoplastic resin such as polyester resin, epoxy resin, urethane resin, polystyrene resin, polyethylene resin, polyamide resin, polyimide resin, polycarbonate resin, silicone resin, fluororesin, etc. To be Of these, a polyimide resin is preferably used from the viewpoint of heat resistance and mechanical strength.

The thickness of the insulating substrate is not particularly limited, but in order to have sufficient mechanical strength and flexibility, it is 2 μm to 500 μm, preferably 10 μm to 150.
It is better to set to μm. Further, in order to improve the flatness and thermal expansion of the insulating substrate, ceramics such as alumina and silicon nitride, or a low linear expansion supporting substrate such as 42 alloy is bonded to a part or the whole surface of the insulating substrate. You may.

The basic shape portion of the contact portion is shown in FIG.
As shown in (a) to (e), the cross-sectional shape is a plane shape,
It may have any other shape such as a concave shape, a hemispherical shape, or a trapezoidal shape, and does not necessarily have to be formed so as to project outward from the surface of the insulating substrate, and the contact formed on the inspection object. It can be arbitrarily set depending on the layout and shape of the target portion. In FIG. 4, hatching of the cross section is omitted.

The material for the basic shape portion is not particularly limited as long as it has conductivity regardless of whether it is a conductor or a semiconductor, but a known good conductor metal is preferable. For example, gold, silver,
Copper, platinum, lead, tin, nickel, cobalt, indium,
Examples include single metals such as rhodium, chromium, tungsten, and ruthenium, various alloys containing these, or a laminated structure formed by combining these. In the case of the laminated structure, the defects of the contact materials of the respective layers are compensated for each other, and a contact portion which is less deteriorated by repeated contact opening and closing is formed.

The shape of the fine protrusions is not particularly limited, and as shown in the sectional views of FIGS. 5 (a) to 5 (d), a conical shape, a cylindrical shape, a hemispherical shape, and further fine protrusions on the fine protrusions. The shape in which the is formed is included. In FIG. 5, hatching of the cross section is omitted. The contact target part may be a conductor having a hardness of 200 Hk or less. Above all, since the surface of the solder ball is covered with an oxide film, the oxide film penetrates through the oxide film, and in order to make good contact with the unoxidized part of the deep layer. Also, it is preferable that the tips of the minute projections be sharp.

The height of the fine protrusions is preferably 0.1 μm to 9 μm from the surface of the basic shape portion, and particularly 0.3 μm to 5 μm.
μm is preferred. If the height of the fine protrusions is 0.1 μm or less, a high contact pressure is required to break through the oxide film covering the surface of the contact target portion and obtain good contact. Therefore, the contact target portion made of a soft metal may be deformed. Further, when the height of the minute protrusions is 9 μm or more, the contact target portion made of a soft metal is largely recessed, and when the object to be inspected is mounted as a product on a substrate or the like, the recess becomes a cavity and becomes a product. This will have an adverse effect such as poor conductivity.

The method of forming the fine projections is not particularly limited, and it can be formed by a method such as mechanical method or chemical etching. Among them, the microprojections formed by depositing the contact material by electroless plating or electrolytic plating can easily form microprojections with a height and shape suitable for breaking through the oxide film of the contact target part. It is possible to do so, which is preferable. When formed by electrolytic plating, the state of the obtained metal surface changes by setting the current density to a high value, adjusting the amount of brightener in the plating solution, adding organic substances such as silicone, and impurity metal ions. . When it is formed by the electroless plating method, the amount of deposited metal and the surface condition of the obtained metal change depending on the plating time, the metal ion concentration, the temperature, the PH, and the like.

The material used for the fine protrusions is not particularly limited as long as it has conductivity.
For example, gold, silver, copper, platinum, lead, tin, nickel, cobalt, indium, rhodium, chromium, tungsten,
Examples include single metals such as ruthenium, and various alloys containing these. Alternatively, a stacked layer formed by combining these materials may be used.

The portion to be contacted may be a conductor having a hardness of 200 Hk or less. Above all, the solder balls that are generally used are covered with an oxide film and penetrate the oxide film.
In order to make good contact with the unoxidized portion of the deep layer, it is preferable that the material of the fine protrusions is a hard metal.
If the material of the micro-projections is not hard metal, the contact parts with the micro-projections are coated with hard metal on top of them to make the projections durable such as deformation resistance and wear resistance. It is preferable to add. Above all, from the viewpoint of strength, the hard metal has a hardness of 300 Hk to 1200 Hk.
Is more preferable, and further 700 Hk to 1
The range of 200 Hk is more preferable. Such materials include, but are not limited to, hard metals such as rhodium, ruthenium, and palladium.

The conductive circuit is formed on the insulating substrate at the same surface as the position where the contact portion is to be formed, at a position corresponding to the inside or the back surface so as to be electrically connected to the contact portion. Further, the conductive circuit includes, in addition to the circuit pattern formed by the conductor / semiconductor, elements constituting a circuit such as a contact portion, a coil, a resistor, and a capacitor. The material of the conductive circuit is not particularly limited as long as it has conductivity regardless of a conductor or a semiconductor, but a known good conductor metal is preferable.
For example, gold, silver, copper, platinum, lead, tin, nickel, iron, cobalt, indium, rhodium, chromium, tungsten,
A single metal such as ruthenium, or various alloys containing these as components, such as solder, nickel-tin, gold-cobalt,
Examples include iron-nickel and iron-cobalt. Also,
A laminated structure may be formed by using plural kinds of the above metals and alloys.

When the conductive circuit is formed as a circuit pattern, the thickness thereof is not limited, but from the viewpoint of reducing the resistance value as an electric path and the workability such as chemical etching, the thickness is set to 1 μm to 200 μm, particularly 5 μm to 50 μm. It is preferable to set. As a method of forming a conductive circuit, a method of directly drawing and forming a target circuit pattern on an insulating substrate (additive method) and a method of removing other conductor portions so as to leave the target circuit pattern (Subtractive method).

As shown in FIG. 2D or 2E, when the basic shape portion projects from the surface of the insulating substrate, a conductive path for connecting the conductive circuit and the contact portion is formed. The diameter of the through-hole is not limited, but it is preferable to increase the diameter of the through-hole so that the adjacent through-holes are not connected to each other because the electrical resistance of the conductive path can be reduced. The practical hole diameter of the through hole is 5 μm to 200 μm, particularly 10 μm.
About 80 μm is preferable. In addition, the through holes are formed not only perpendicularly to the surface of the insulating substrate but also at a predetermined angle with respect to the surface of the insulating substrate, and the conductive holes are slightly offset from the positions directly behind each other. The conductive circuit and the bump contact can be electrically connected.

The conductive path may be formed in the through hole so as to connect the contact portion and the conductive circuit, and may be formed by filling the through hole with a conductive material, such as through hole plating. An example is one in which a layer of a conductive substance is formed on the wall surface of the through hole. Examples of the method of forming the conductive path include a method of mechanically inserting a conductive substance into the through hole, a film forming method such as a CVD method, and electrolytic plating or electroless plating. Among these methods, a method of exposing a conductive circuit in the through hole and filling the through hole with a conductive substance by electrolytic plating using the conductive circuit as a negative electrode is a reliable conduction method and simple. Therefore, it is preferable.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A conductive contact portion made of copper is provided on one side of an insulating substrate made of a polyimide resin having a thickness of 50 μm,
Electrolytic matte copper plating (bath temperature 25 ° C, 4A / d
m ² · 5 minutes), and further gold strike plating (bath temperature 25 ° C, 3 A / dm ² · 30 seconds), gold plating (bath temperature 68 ° C, 0.6 A / dm ² · 30 seconds) on the contact surface. ) And rhodium plating (bath temperature 50 ° C, 1.9 A / dm ² · 2)
Min.) To form a plurality of protrusions having a height of 1 μm to 1.5 μm. Next, using the probe structure manufactured by the above method, a continuity test of an IC chip using a solder ball as a contact target part is conducted. When the contact resistance is 0.2Ω or less, the contact pressure is 1 contact point. It was 7 g per part, and the amount of deformation of the solder balls was 10% or less.

[Embodiment 2] A conductive contact portion made of copper is provided on one side of an insulating substrate made of a polyimide resin having a thickness of 50 μm, and the contact portion is electroless copper plated (manufactured by EBARA Eugelite: Inter Plate, bath temperature 70 ° C., 20 minutes), and then gold strike plating (bath temperature 25 ° C., 3 A / dm ² · 30 seconds), gold plating (bath temperature 68) on the contact surface.
C., 0.6 A / dm ² · 30 seconds) and rhodium plating (bath temperature 50 ° C., 1.9 A / dm ² · 2 minutes) were performed to form a plurality of protrusions having a height of 2.5 μm to 3 μm. Next, using the probe structure manufactured by the above method, a continuity test of a chip size package using a solder ball as a contact target part was conducted. The contact pressure when the contact resistance was 0.2Ω or less was 1 It was 5 g per contact part, and the amount of deformation of the solder balls was 8% or less.

[Comparative Example 1] A conductive contact portion made of copper is provided on one side of an insulating substrate made of a polyimide resin having a thickness of 50 μm, and the contact portion is subjected to gold strike plating (bath temperature 25
℃, 3A / dm ² · 30 seconds), gold plating (bath temperature 68 ℃,
0.6 A / dm ² · 3 minutes) to form a plurality of fine protrusions having a height of 0.05 μm. Next, using a probe structure manufactured by the above method, a continuity test of an IC chip using a solder ball as a contact target part was conducted. In order to obtain a low contact resistance, a contact pressure of 30 g per contact part was used. Therefore, the amount of deformation of the solder balls was 25% or more, and reflow was necessary before mounting on the substrate.

Comparative Example 2 A conductive contact made of copper is provided on one side of an insulating substrate made of polyimide resin having a thickness of 50 μm, and electrolytic matte copper plating (bath temperature 25
℃, 8A / dm ² · 20 minutes), and further, the surface of the contact portion is gold strike plated (bath temperature 25 ° C, 3A / dm ² ·
30 seconds, gold plating (bath temperature 68 ° C, 0.6 A / dm ² ·
1 minute) was performed to form a plurality of protrusions having a height of 10 μm.
Next, using the probe structure manufactured by the above method, a continuity test of the IC chip using a solder ball as a contact target portion was performed. The contact pressure required to obtain low contact resistance is 1
Although the amount per contact point was 5 g, a recess having a depth of 10 μm to 15 μm was formed on the surface of the solder ball, and reflow was necessary before mounting on the substrate.

[0037]

According to the probe structure of the present invention, particularly when a solder ball is used as the contact target portion, the oxide film can be reliably pierced, and the contact target portion is not greatly depressed, and the contact pressure is low. , Can get good contact.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an example of a probe structure of the present invention.

FIG. 2 is a cross-sectional view schematically showing another aspect of the probe structure of the present invention.

FIG. 3 is a cross-sectional view schematically showing another aspect of the probe structure of the present invention.

FIG. 4 is a cross-sectional view showing an aspect of a basic shape portion of a contact portion formed in the probe structure of the present invention.

FIG. 5 is a cross-sectional view showing an aspect of minute protrusions included in the contact portion in the probe structure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Conductive circuit 3 Contact part 3a Basic shape part 3b Micro protrusion 4 Conducting path 5 Inspected object 6 Contact target part 7 Oxide film

Claims (7)

[Claims] 1. A probe structure for contacting a conductor having a surface hardness of 200 Hk or less, wherein a contact portion provided on one surface of an insulating substrate and either surface or the inside of the insulating substrate. Has a structure in which it is electrically connected to a conductive circuit provided in, and the contact portion includes a basic shape portion and one or more minute protrusions formed on the surface of the basic shape portion. The probe structure has a height of 0.1 μm to 9 μm. 2. The hardness of the surface of the minute protrusion of the contact portion is 300.
The probe structure according to claim 1, which has a Hk to 1200 Hk. 3. The conductor to be contacted with the probe structure has a surface covered with an oxide film.
Or the probe structure according to 2. 4. The conductor to be contacted with the probe structure is a metal ball or a metal bump.
The probe structure described. 5. The probe structure according to claim 1, wherein the minute protrusions of the contact portion are formed by depositing by electroless plating, and are formed so as to protrude from the surface of the basic shape portion. . 6. The minute protrusions of the contact portion are formed by electrolytic plating using a conductive circuit as a negative electrode, and are formed so as to protrude from the surface of the basic shape portion. 4. The probe structure according to 4. 7. The probe structure according to claim 1, wherein the entire contact portion including the fine protrusions is laminated in a plurality of layers so that the hardness of at least the surface is 300 Hk to 1200 Hk.