JP3046498B2 - probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe,
The present invention relates to a device that can be suitably connected to a contact object having a plurality of contacted parts, such as a wafer, a semiconductor element, and a circuit board.

[0002]

2. Description of the Related Art In recent years, the number of signal wirings, connection terminals, electrodes, and the like on contact objects has increased due to the high integration of semiconductor elements or the high-density mounting of electronic components on circuit boards. Pitch is also becoming finer. The characteristics and quality of these electronic components are inspected at each stage of the manufacturing process. For example, a stage in which a large number of LSIs are formed on a silicon wafer or a stage in which LSIs are divided (hereinafter, the products in these stages are referred to as In the case of a "bare chip"), a probe capable of simultaneously contacting a plurality of fine inspection objects in a region of about 4 to 15 mm square with high reliability is required. Also, when the bare chip is directly incorporated into a product, or when a substrate on which a large number of electronic components are mounted at a high density is incorporated into a product together with other circuit blocks, similarly to the above-described process inspection, a large number of densely packed substrates are provided. Therefore, a probe and a connection structure that can be connected to the contact object with high reliability are required.

In order to make a temporary contact or a permanent connection with a contact object formed at a high density as described above, a flexible circuit board having projecting bump contacts on the surface is used. Probes are known. In order to make a large number of combinations of the bump contact and the contact object in such a probe preferably contact all but not all, the present applicant has proposed a structure in which an elastic body is provided at a position corresponding to the back surface of the bump contact. ing. (Japanese Patent Application No. 5-21314)
See No. 6, "Method of connecting flexible circuit board to contact object and structure thereof". FIG. 3 is a schematic diagram partially showing a cross section of the structure of a probe in which an elastic body is provided at a position corresponding to the back surface of the bump contact, and the connection state with a contact object when using the structure. is there. In the figure, A1 is the probe, which includes a plurality of bump contacts 2 provided on one surface (upper surface in the figure) of an insulating film 1 and a circuit pattern 3 provided on an inner layer of the film 1. Are conducted to form a base a1, and an elastic body 4a is provided on the base at least at a position corresponding to the back surface of the bump contact. This probe A
A plurality of bump contacts 2 and a contact object B such as an electronic component
The probe A1 and the object to be contacted B are laminated such that the plurality of contacted parts b correspond to and make contact with each other, and are laminated on the entire surface of the laminate by the pressing means 6 sandwiching the laminate in the laminating direction. The pressing force F in the direction is applied, and the contacted portion b and the bump contact 2 are in contact with each other. At this time, the elastic body 4
a absorbs variations in the height of each bump contact and errors in the thickness of each portion accumulated in the stacking direction by elastic deformation, and acts so that each bump contact 2 contacts the contacted portion b. ing.

[0004]

However, in the probe structure as described above, when the elastic body is soft and has a large deformation, the applied pressure is not sufficiently transmitted as the contact pressure of the bump contact. However, the elastic body is only greatly deformed. As a result, as shown by the dashed line X in FIG. 3, the base is also greatly deformed from the state before pressing. According to the present invention, the phenomenon that the large deformation of the elastic body and the base body becomes permanent deformation during long-time use, thereby weakening the contact force between the bump and the contacted object and reducing the contact reliability. Raised a new issue. Conversely, when the elastic body is hard and hardly deformed, the variation in the height of each bump is not absorbed and a contact failure occurs, which is also a new problem.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to allow a bump contact on a probe to remain in contact with a contact portion of a contact object which is formed minutely and at a high density, and An object of the present invention is to provide a probe whose contact reliability hardly decreases over time.

[0006]

The probe of the present invention has the following features. (1) A substrate formed by conducting a plurality of bump contacts provided on at least one surface of a flexible insulating film and a circuit pattern provided on any surface or inside of the insulating film. An elastic body is provided at least at a position corresponding to the back surface of the bump contact, and the elastic body has a tensile modulus of 0.5 kg / mm ^{2 to} 1200 kg / mm ² ,
A probe having a thickness of 0.01 mm to 2 mm. (2) The probe according to (1), wherein the elastic body is provided so as to be integral with or detachable from the base. (3) The probe according to (1) or (2), wherein the elastic body is made of a polyimide resin, a fluorine resin or a silicone resin.

[0007]

[Effect] The tensile elastic modulus of the elastic body is 0.5 kg / mm ² -1.
Limited to 200 kg / mm ² and its thickness is 0.01 mm
By limiting the thickness to ２2 mm, the elastic body exhibits the most preferable deformation for a plurality of sets of contact when the probe is brought into contact with the contact object and pressurized. This prevents the substrate from sagging locally or entirely unnecessarily. Therefore, an appropriate contact pressure is transmitted to each bump contact, and plastic deformation of the base is suppressed.

[0008]

The present invention will be described below in more detail with reference to examples. FIG. 1 shows a probe according to one embodiment of the present invention;
It is a schematic diagram which shows the connection state with the contact object at the time of using it in partial cross section. As shown in FIG.
Is the probe of the present invention, at least one surface side (upper surface in the figure) of the insulating film 1 having flexibility .
Are electrically connected to the circuit pattern 3 provided on any surface or inside of the insulating film to form the base a. Of the substrate a,
The elastic body 4 is provided at least at a position corresponding to the back surface of the bump contact.
Is provided. This elastic body has a tensile modulus of elasticity of 0.5 k.
g / mm ^{2 to} 1200 kg / mm ² , thickness 0.01 mm
２2 mm.

FIG. 1A shows a state before pressurization.
A plurality of bump contacts 2 of the probe A of the present invention and a plurality of contacted parts b of the contact object B are laminated so as to face each other and correspond to each other. Shows a state where is provided. FIG.
(B) shows a state during pressurization, in which a pressing force F is applied to the entire surface of the stack by the pressurizing means 6 so that the elastic body 4 absorbs variations in the height of individual bump contacts. 2 shows a state in which a plurality of bump contacts and a plurality of contacted portions corresponding thereto are in contact with each other.

The insulating film may be any as long as it has insulating properties and flexibility. Examples of such materials include polyester resins, epoxy resins, urethane resins, polystyrene resins, polyethylene resins, polyamide resins, polyimide resins, ABS resins, polycarbonate resins, silicone resins, and fluorine resins. And the like, and can be used regardless of thermosetting thermosetting properties. In particular, in consideration of heat resistance and storage stability, a polyimide resin is a preferable material.

[0011] The material of the bump contact is gold, silver, copper, rhodium, platinum, palladium,
A good conductor such as nickel, tin, and solder, or various alloys containing these as main components are used. In addition to the formation of only these single metals, a multi-layer structure of a plurality of types of metals may be used according to the state of the contacted parts, the use conditions, and the like. For example, when repeatedly used under pressure or when it is necessary to cut into the contacted part, use a relatively hard metal such as nickel as the core metal of the bump contact, and use rhodium as the surface metal. It is preferable to form the multilayered structure used. As a method for forming bump contacts, plating methods such as electrolytic plating and electroless plating, wire bonding methods, cream solder potting methods, and the like can be adopted. Among these methods, plating methods such as electrolytic plating are fine. This is a preferable method because it is easy to form a simple projecting contact and the workability is good.
The shape of the bump contact is usually a protruding hemisphere,
There is no need to project depending on the shape of the contacted part of the partner. For example, if the shape of the contacted part of the other party is a protrusion, the bump shape may be flat, and further,
It may be depressed against the surface of the insulating film.

The material of the circuit pattern may be copper, nickel, solder, gold, silver, etc., as long as it is used as a general circuit board circuit material. As a method of forming a circuit pattern, a subtractive method or an additive method can be used. The subtractive method is a method in which one to several conductor layers are laminated on the insulating film 1 by vapor deposition, pressure bonding, etc., and this is etched to form a circuit pattern. The additive method is a method of directly forming a circuit pattern on the insulating film 1 by plating, vapor deposition, or the like. The place where the circuit pattern is formed is
The surface on the side on which the bump contact is provided on the insulating film, the surface on the opposite side, the inner layer, and the like are arbitrary. Usually, the circuit pattern is formed so as to pass through a place corresponding to the back side of the bump contact with respect to the insulating film, and in many cases, these are conducted inside the insulating film. Further, a structure in which a bump contact and a circuit pattern coexist on the same surface of an insulating film, and each is electrically connected on the surface is exemplified.
In the circuit pattern provided on the surface of the insulating film,
As shown in FIG. 1, by coating the protective film 5,
It is preferable to ensure insulation from the outside and protect from mechanical damage.

[0013] The elastic body has the height of the bump contact,
This is to absorb the variation of the dimension accumulated in the height direction by bending. By limiting the properties and dimensions of the elastic body as follows, large plastic deformation of the base is suppressed, and deterioration of the elastic body itself with time is also suppressed. As a property of the elastic body, the tensile elastic modulus is 0.5
and ^{kg / mm 2 ~1200kg / mm 2} . Among these ranges, a particularly preferred range is 0.8 kg / mm ²
８００800 kg / mm ² . The tensile modulus is JIS
It is measured according to K7113. Materials that can satisfy such properties include polyimide-based resins, fluorine-based resins, and silicone-based resins. As the polyimide resin, modified polyimides such as polyamideimide and polyetherimide can be used in addition to aliphatic polyimide, alicyclic polyimide and aromatic polyimide.
Specifically, Kapton H (DuPont), Upilex S (Ube Industries) and the like are listed. PTFE (polytetrafluoroethylene), PFA as fluorine resin
(Perfluoroalkoxy) resin, FEP (tetrafluoroethylene-hexafluoropropylene copolymer), FPE (perfluoroalkoxy-hexafluoropropylene) resin, ETFE (ethylene-tetrafluoroethylene) resin, PCTFE (polychlorotrifluoroethylene resin) , ECTFE (ethylene-chlorotrifluoroethylene) resin, PVDF (polyvinylidene fluoride) and the like. Specifically, Teflon (DuPont) or the like can be used. The silicone resin is an organosilicon polymer having a siloxane (-Si-O-Si-) bond, and specific examples include KE7000 series (Shin-Etsu Chemical Co., Ltd.).

The dimensions of the elastic body include its thickness (ie,
Bump contact height direction) 0.01mm to 2mm
And Among these ranges, the preferred range is 0.0
5 mm to 1 mm, a particularly preferred range is 0.1 mm to 0.1 mm.
5 mm.

When the elastic body has a tensile modulus of elasticity of less than 0.5 kg / mm ² or a thickness of more than ² mm with respect to the above-mentioned limited conditions, when the probe is in contact with the portion to be contacted, The elastic body deforms excessively. As a result, the base also locally deforms greatly, becomes permanent during use for a long time, and weakens the contact between the bump and the contacted object. On the other hand, if the tensile elastic modulus is more than 1200 kg / mm ² or the thickness is less than 0.01 mm, it is necessary to absorb variations in the height of the bumps and other dimensions accumulated in the height direction. For example, a contact lower than the surrounding bump contact does not come into contact, and a contact failure occurs.

The elastic body is provided integrally or detachably with the base. The method of forming the elastic body can be broadly divided into a method of directly forming the elastic body and a method of forming the elastic body separately and joining it to the base. As a method of directly forming on a substrate, a method of applying and drying a polymer precursor solution or solution on a substrate, a method of forming using a mold or the like, various film forming methods, and the like are useful. Shape processing may be performed by laser processing, erosion, or the like. If the material of the back side surface of the bump contact, such as the protective film 5 shown in FIG. 1, is made of polyimide, fluorine resin or silicone resin having a thickness of 0.01 to 2 mm, it is directly processed. It is also possible. As a method of forming the elastic body separately from the base, almost all molding techniques are used. Further, the bonding with the base may be a permanent bonding and fixing with an adhesive or welding, or may be simply detachable and merely superimposed on the elastic body and the base during use.

FIG. 1 shows the shape of the elastic body.
(A) and those shown in FIGS. 2 (a) to (d).
The embodiment shown in FIG. 1A is an example in which the elastic bodies are formed individually and unrelated to each other only at positions corresponding to the back surfaces of the bump contacts of the substrate. The individual shape of the elastic body is
Pillars, cones, frustums, spindles, and composites of these, having a cross-section perpendicular to the compression direction, such as circles, ellipses, polygons, and various irregularities, or those with a hollow interior And various parameters such as a cross-sectional area and a natural length can be selected for each of these.

The embodiment shown in FIG. 2A is an example in which the elastic body is formed in a plate shape. Such an embodiment is one of practically preferable embodiments in terms of manufacturing cost and ease of disposition on the substrate. The plate-shaped configuration may be a single material or a laminate of a plurality of materials. further,
Various through holes and recesses are provided at predetermined positions of the plate-like elastic body,
It is also free to change the thickness of the layer. FIG. 2 (b)
1 is an example in which the embodiment of FIG. 1A and the embodiment of FIG. 2B are combined. In the drawing, an elastic body 41 individually formed at a position corresponding to the back surface of the bump contact is integrated by a plate-like elastic body 42. With such a configuration, both the independent compressibility, which is the advantage of the elastic body formed separately, and the low cost, which is the advantage of the plate-like elastic body, and the ease of disposition on the substrate, are both provided. Become. FIGS. 2C and 2D are diagrams showing examples in which an elastic body 41 and a plate-like elastic body 42 which are individually formed are formed using different materials. By such a combination, it is possible to distribute an arbitrary load to an arbitrary place. Depending on the purpose, the individually formed elastic bodies may be further subdivided and formed of different materials.

The contact object is a bare chip level LSI.
Or a TAB film to which the bare chip is connected, a multi-chip in which these are integrated, or various electronic components, a circuit board on which a large number of the electronic components are mounted, or a small one such as a probe. Any contact may be used, up to a product-level large one, and a contact point, a conductor portion, or the like formed on these surfaces is a contacted portion. In addition, the connection state may be a short-time contact like a relay contact, a product that is permanently fixed in a contacted and pressurized state to be a finished product, or a product that is welded and fixed after the contact, in various states. Used.

[Experiment 1 for Confirming Contact Reliability] In this experiment, the elastic body was formed into the shape shown in FIG.
kg / mm ² silicone resin, thickness 1mm,
Three types of samples of 2 mm and 3 mm were produced. A heat cycle test was performed by bringing the three types of probes having different thicknesses of the elastic body into contact with an A1 wafer as a contact target. The contact resistance between the bump contact and the A1 wafer was measured before and after the heat cycle test. As a result, the samples having the elastic body thickness of 1 mm and 2 mm showed almost no change in the contact resistance before and after the heat cycle test. On the other hand, for the sample having a thickness of the elastic body of 3 mm, a large increase (deterioration) of the resistance value was observed. Thereby, good contact reliability of the probe of the present invention was confirmed. When the deformation of the bump contact was evaluated by SEM observation after the test, the probe having a thickness of 1 mm and 2 mm was not deformed, whereas the probe having a thickness of 3 mm was not deformed.
In the case of, the deformation was clearly confirmed.

[Contact Reliability Confirmation Experiment 2] In this experiment, the elastic body was made of polyimide having a tensile elastic modulus of 350 kg / mm ² , and the thickness of each of the three types of samples was 7 μm and 125 μm.
The contact reliability of the bumps was confirmed in the same manner as in Experiment 1 except that 20 pieces having a thickness of m and a thickness of 125 μm were superposed and adhered to each other to have a thickness of 2.5 mm. As a result, for a sample having a thickness of 125 μm of the elastic body,
Good contact was obtained with all bumps, and there was no change in the contact resistance of the bumps. On the other hand, the thickness of the elastic body is 7 μm
As for the sample of No., some samples had poor contact. However, there was no change in the contact resistance in the case of contact. Further, in the sample having the thickness of the elastic body of 2.5 mm, although contact was made at all the bump contacts, an increase (deterioration) in the contact resistance of the bump was observed.

[Contact Reliability Confirmation Experiment 3] In this experiment, except that the thickness of the elastic body was fixed to one kind of 125 μm, and the material was polyimide having a tensile modulus of 350 kg / mm ² and 1300 kg / mm ² , The contact reliability of the bumps was confirmed in the same manner as in Experiment 1 above. As a result, with respect to the sample having a tensile modulus of 350 kg / mm ² , contact was made with all the bumps, and the contact resistance did not change. On the other hand, in the case of the sample of 1300 kg / mm ² , there were several points of poor contact. However, there was no change in the contact resistance in the case of contact.

[Experiment 4 for Confirming Contact Reliability] In this experiment, the elastic body was made of a fluorine-based resin, and the tensile elasticity was 6%.
PTFE (polytetrafluoroethylene) of 0 kg / mm ² , and the thickness of each of the three sample types was 4 μm,
The contact reliability of the bumps was confirmed by the same method as in Experiment 1 except that the bumps were set to 3 mm and 3 mm. As a result, the thickness 1
For the mm sample, contact was achieved at all bumps and the contact resistance did not change. On the other hand, in the case of the sample having a thickness of 4 μm, poor contact occurred. However, there was no change in the contact resistance in the case of contact. In the case of 3 mm, although contact was made with all the bumps, an increase (deterioration) in the contact resistance of the bumps was observed.

From the above confirmation experiment, good contact reliability of the probe according to the present invention was confirmed.

[0025]

As described in detail above, according to the present invention,
As with bare chip LSIs, it is possible to make contact with the bumps on the probe without leaving any contact with the contacted parts formed at a high density, and the contact reliability decreases over time. It is difficult. As a result, it is possible to provide a probe useful for a process inspection of a small electronic component device product or a connection portion inside an external product.

[Brief description of the drawings]

FIG. 1 is a schematic diagram partially showing a connection state between a probe according to an embodiment of the present invention and a contact object when the probe is used.

FIG. 2 is a cross-sectional view schematically showing a specific mode of an elastic body.

FIG. 3 is a schematic diagram partially showing a cross section of a conventional structure of a probe provided with an elastic body and a connection state between the probe and a contact target when the probe is used.

[Explanation of symbols]

 Reference Signs List A probe a base B contact object b contacted part 1 insulating film 2 bump contact 3 circuit pattern 4 elastic body 5 protective film

Claims (3)

(57) [Claims] A plurality of bump contacts provided on at least one surface of a flexible insulating film and a circuit pattern provided on any surface or inside of the insulating film are electrically connected. An elastic body is provided on at least a position corresponding to the back surface of the bump contact of the base body, and the elastic body has a tensile modulus of elasticity of 0.5 kg / mm ^{2 to} 1200 kg.
/ Mm ² , and a thickness of 0.01 mm to ² mm. 2. The probe according to claim 1, wherein the elastic body is provided so as to be integral with or detachable from the base. 3. The probe according to claim 1, wherein the elastic body is made of a polyimide resin, a fluorine resin, or a silicone resin.