JPH07335287A - Probe - Google Patents

Abstract

PURPOSE:To provide a probe, wherein a bump contact on the probe can be entirely brought into contact relating to a contacted part of a contact object, formed fine in high density, further with reliability of this contact difficult to decrease with the lapse of time. CONSTITUTION:A probe A is characterized by providing an elastic body 4 in a position corresponding to at least a reverse side of a bump contact in a base body (a), constituted by conducting a plurality of the bump contacts 2 provided in at least one surface side of an insulating film l to a circuit pattern 3 provided in an arbitrary spot of this film, and by setting this elastic body to 0.5kg/mm<2> to 1200kg/mm<2> tensile elastic modulus and 0.01mm to 2mm thickness. The elastic body may be integrally or mountably/demountably formed relating to the base body. Material of the elastic body is preferable polyimide system resin, fluorine system resin and silicone resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to probes, and in particular to
The present invention relates to a wafer, a semiconductor device, a circuit board, or the like that can be suitably connected to a contact object having a plurality of contacted portions.

[0002]

2. Description of the Related Art In recent years, the number of signal wirings, connection terminals, electrodes, etc. on these contact objects has increased due to the high integration of semiconductor elements or high density mounting of electronic components on a circuit board. The pitch is also getting smaller. The characteristics and quality of these electronic components are inspected at each stage of the manufacturing process. For example, a stage where a large number of LSIs are formed on a silicon wafer or a stage where the LSIs are divided (hereinafter, these stages are referred to as In the "bare chip"), a probe capable of contacting a plurality of minute inspection objects densely in a region of 4 to 15 mm square with high reliability at the same time is required. Also, when the bare chip is directly incorporated into a product, or when a board on which a large number of electronic components are mounted at high density is incorporated into a product together with other circuit blocks, a large number of densely packed substrates are collected as in the above process inspection. It is necessary to provide a probe and a connection structure capable of connecting to the contact object with high reliability.

A flexible circuit board having bump-shaped bump contacts on its surface is used to make a temporary contact or a permanent connection to the above-mentioned minute and high-density contact object. Probes are known. In order to make all of the many combinations of bump contacts and contact targets in such a probe suitable for contact, the applicant of the present application has proposed a structure in which an elastic body is provided at a position corresponding to the back surface of the bump contacts. ing. (Japanese Patent Application No. 5-21314
See No. 6, "Method and structure for connecting flexible circuit board to contact object". ) FIG. 3 is a schematic diagram partially showing a cross-section of a structure of a probe in which an elastic body is provided at a position corresponding to the back surface of the bump contact, and a connection state with a contact object when the elastic body is used. is there. In the figure, A1 is the probe, and includes a plurality of bump contacts 2 provided on one surface (an upper surface in the figure) of the insulating film 1 and a circuit pattern 3 provided on an inner layer of the film 1. Is conducted to form the base body a1, and the elastic body 4a is provided at a position corresponding to at least the back surface of the bump contact on the base body. This probe A
A plurality of bump contacts 2 of 1 and a contact object B such as an electronic component
The probe A1 and the contact object B are laminated so that the plurality of contacted portions b correspond to each other and are brought into contact with each other. A 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
The elastic deformation a absorbs variations in the height of each bump contact and an error in the thickness of each portion accumulated in the stacking direction, and acts to bring all the bump contacts 2 into contact with 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 amount, 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, the base body is also largely deformed from the state before the pressurization, as indicated by the one-dot chain line X in FIG. According to the present invention, the large deformation of the elastic body and the base body causes permanent deformation during long-term use, which weakens the contact force between the bump and the object to be contacted and reduces contact reliability. The person picked it up as a new issue. On the contrary, when the elastic body is hard and difficult to be deformed, the phenomenon that the variation in the height of each bump is not absorbed and the contact failure occurs is also taken as a new problem.

An object of the present invention is to solve the above problems, and it is possible to make contact with a contacted portion of a contact object, which is minute and has a high density, without leaving any bump contact on the probe. It is an object of the present invention to provide a probe whose contact reliability does not easily deteriorate with time.

[0006]

The probe of the present invention has the following features. (1) At least a bump contact of a base body in which a plurality of bump contacts provided on at least one surface side of an insulating film and a circuit pattern provided on either surface or inside of the insulating film are electrically connected An elastic body is provided at a position corresponding to the back surface of the elastic body, and the elastic body has a tensile modulus of 0.5 k.
g / mm ^{2 to} 1200 kg / mm ² , thickness 0.01 mm
A probe having a size of ˜2 mm. (2) The probe according to (1), wherein the elastic body is provided integrally with or detachably from the base body. (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]

[Function] The tensile modulus of elasticity of the elastic body is 0.5 kg / mm ² to 1
Limited to 200 kg / mm ² and its thickness is 0.01 mm
By limiting the width to ˜2 mm, the elastic body exhibits the most preferable deformation for a plurality of sets of contacts when the probe and the contact object are brought into contact with each other and pressed. This prevents the substrate from deflecting more than necessary locally or globally. Therefore, an appropriate contact pressure is transmitted to each bump contact, and plastic deformation of the substrate is suppressed.

[0008]

The present invention will be described in more detail with reference to examples. FIG. 1 shows a probe according to an embodiment of the present invention,
It is a schematic diagram which partially shows a connection state with a contact target object in a cross section when using it. As shown in FIG.
Is a probe of the present invention, and is provided on a plurality of bump contacts 2 provided on at least one surface side (an upper surface in the figure) of the insulating film 1 and on any surface or inside of the insulating film. The circuit pattern 3 is electrically connected to the base body a. The elastic body 4 is provided at a position corresponding to at least the back surface of the bump contact on the base body a. This elastic body has a tensile elastic modulus of 0.5 kg / mm ² to 1
It is characterized by having a thickness of 200 kg / mm ² and a thickness of 0.01 mm to ² 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 portions b of the contact object B are laminated so as to face each other, and the pressing means 6 is sandwiched in the stacking direction from both sides. Is provided. Also, FIG.
(B) shows a state during pressurization, in which a pressing force F in the compression direction is applied to the entire surface of the stack by the pressurizing means 6 so that the elastic body 4 absorbs variations in height of individual bump contacts. In the preferred deflection, a plurality of bump contacts and a plurality of contacted portions corresponding thereto are in contact with each other.

The insulating film has only to have insulation 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, fluorine resins. , Etc. can be used, and they can be used regardless of their thermosetting properties and thermal flexibility. Particularly, in consideration of heat resistance and storability, a polyimide resin is a preferable material.

The material of the bump contact is gold, silver, copper, rhodium, platinum, palladium, similar to general electric contact materials.
A good conductor such as nickel, tin, or solder, or various alloys containing these as main components is used. Further, not only the single metal may be formed, but also a multi-layered structure including a plurality of kinds of metals may be used depending on the state of the contacted portion, the use condition, and the like. For example, when pressure is applied repeatedly and when it is necessary to bite into the contacted part, a relatively hard metal such as nickel is used as the core metal of the bump contact, and rhodium is used as the surface metal. It is preferable to form the multilayer structure used. The bump contact can be formed by a plating method such as electrolytic plating or electroless plating, a wire bonding method, a cream solder potting method, or the like. Among these methods, the plating method such as electrolytic plating is It is a preferable method because it is easy to form such protruding contact points and has good workability.
The shape of the bump contact is usually a protruding hemisphere,
It is not necessary to project depending on the shape of the contacted part of the other party. For example, if the shape of the contacted portion of the other party is a protrusion, the bump shape may be a flat surface.
It may be recessed with respect to the surface of the insulating film.

The material of the circuit pattern may be copper, nickel, solder, gold, silver, or the like, as long as it is used as a circuit material of a general printed circuit board. As a method of forming a circuit pattern, a subtractive method or an additive method can be mentioned. 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 etching is performed to form a circuit pattern. Further, 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 where the bump contact is provided on the insulating film, the surface on the opposite side, the inner layer, etc. are arbitrary. Usually, the circuit pattern is formed so as to pass through a position corresponding to the back side of the bump contact with respect to the insulating film, and these are often electrically connected inside the insulating film. Further, a structure in which the bump contact and the circuit pattern coexist on the same surface of the insulating film and they are electrically connected on the surface is exemplified.
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 to protect it from mechanical damage.

The elastic body is used for the height of the bump contact,
It is intended to absorb the variation of the accumulated dimension in the height direction by bending. By limiting the properties and dimensions of the elastic body as follows, large plastic deformation of the base body is suppressed, and deterioration of elasticity of the elastic body itself with time is suppressed. As the property of the elastic body, the tensile elastic modulus is 0.5.
and ^{kg / mm 2 ~1200kg / mm 2} . Among these ranges, a particularly preferable range is 0.8 kg / mm ²
~ 800 kg / mm ² . The tensile modulus is JIS
It is measured according to K7113. Materials that can satisfy such properties include polyimide resins, fluorine resins, and silicone resins. As the polyimide-based resin, modified polyimides such as polyamideimide and polyetherimide can be used in addition to aliphatic polyimide, alicyclic polyimide or aromatic polyimide.
Specific examples thereof include Kapton H (DuPont) and Upilex S (Ube Industries). Fluorine resin, PTFE (polytetrafluoroethylene), PFA
(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-based resin is an organosilicon polymer having a siloxane (—Si—O—Si—) bond, and specific examples thereof include KE7000 series (Shin-Etsu Chemical Co., Ltd.).

The size of the elastic body is the thickness (that is,
Bump contact height direction), 0.01mm ~ 2mm
And Within this range, the preferred range is 0.0
5 mm to 1 mm, particularly preferably 0.1 mm to 0.
It is 5 mm.

If the elastic body has a tensile elastic modulus of less than 0.5 kg / mm ² or a thickness of more than 2 mm, the probe and the contacted portion are in contact with each other under the above-mentioned limiting conditions. The elastic body deforms excessively. As a result, the base body is also largely deformed locally and becomes permanently deformed during long-time use, weakening the contact between the bump and the contacted object. On the other hand, if the tensile modulus is more than 1200 kg / mm ² or the thickness is less than 0.01 mm, the height of the bump and other variations in the accumulated dimension in the height direction must be absorbed. However, for example, a contact lower than the surrounding bump contact does not reach the contact, resulting in poor contact.

The elastic body is provided integrally with or detachably from the base body. The method of forming the elastic body can be broadly classified into a method of directly forming the elastic body and a method of separately forming and joining with the base body. As a method for directly forming on a substrate, a method of applying a precursor liquid or solution of a polymer on a substrate and drying, a method of forming using a mold, various film forming methods, etc. are useful. Shape processing may be added by laser processing or erosion. If the material of the back surface of the bump contact, such as the protective film 5 as shown in FIG. 1, is made of polyimide, fluororesin 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 body, almost all molding techniques are used. Further, the joining to the base body may be a permanent adhesive fixing by means of an adhesive, welding, or the like, or it may be detachable and simply by superposing the elastic body and the base body upon use.

FIG. 1 shows the shape of the elastic body.
(A), what is shown to Fig.2 (a)-(d) is mentioned.
The embodiment shown in FIG. 1A is an example in which the elastic body is formed individually and independently of each other only at a position corresponding to the back surface of the bump contact of the substrate. The individual shapes of the elastic body are
Columns, cones, frustums, spindles, and their composites, or those with hollow insides, which have circles, ellipses, polygons, various irregular shapes, etc. as the cross-sectional shape perpendicular to the compression direction , And various parameters such as cross-sectional area and 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 a mode is one of the practically preferable modes from the viewpoint of manufacturing cost and ease of disposition on the substrate. The plate-shaped structure may be a laminate of a single material or a plurality of materials. further,
Various through holes and recesses are provided at predetermined positions of the plate-shaped elastic body,
It is also free to vary the layer thickness. Figure 2 (b)
The mode shown in is an example of a combination of the mode of FIG. 1 (a) and the mode of FIG. 2 (b). In the figure, elastic members 41 individually formed at positions corresponding to the back surface of the bump contact are integrated by a plate-shaped elastic member 42. With such a configuration, it has both the independent compressibility which is an advantage of the elastic body formed individually, and the low cost which is an advantage of the plate-like elastic body and the ease of disposing on the substrate. Become. 2C and 2D are diagrams showing an example in which the elastic body 41 and the plate-shaped elastic body 42, which are individually formed, are formed by using different materials. With such a combination, it becomes 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, various electronic components, a circuit board on which a large number of the electronic components are mounted, or a probe or the like Any type up to a large product level product may be used, and the contacts, conductors, etc. formed on these surfaces serve as the contacted parts. In addition, the connection state is such that from a short time contact like a relay contact, it is a fixed product that is permanently fixed in a contacted and pressurized state, or it is welded and fixed after contacting, and in various states. Used.

[Contact Reliability Confirmation Experiment 1] In this experiment, the elastic body was formed into the shape shown in FIG.
Using a kg / mm ² silicone resin, the thickness is 1 mm,
Three types of samples of 2 mm and 3 mm were produced. A heat cycle test was conducted by bringing three types of probes having different elastic body thicknesses into contact with an A1 wafer as a contact object. The contact resistance between the bump contact and the A1 wafer was measured before and after the heat cycle test. As a result, regarding the samples with elastic body thicknesses of 1 mm and 2 mm, there was almost no change in the contact resistance before and after the heat cycle test. On the other hand, a large increase in resistance value (deterioration) was observed in the sample having the elastic body having a thickness of 3 mm. This confirmed good contact reliability of the probe of the present invention. Further, when the deformation of the bump contact after the test was evaluated by SEM observation, the probes having no thickness of 1 mm and 2 mm had no deformation, whereas the thickness of 3 mm.
Regarding the one, the deformation was clearly confirmed.

[Contact Reliability Confirmation Experiment 2] In this experiment, the elastic body was 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 by the same method as in Experiment 1 above, except that 20 sheets having a thickness of 125 μm and a sheet having a thickness of 125 μm were superposed and bonded to each other to have a thickness of 2.5 mm. As a result, for a sample with an elastic body thickness of 125 μm,
Good contact was obtained with all the 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
With respect to the sample No. 1, several points had poor contact. However, there was no change in contact resistance for those that contacted. Further, regarding the sample in which the thickness of the elastic body was 2.5 mm, although contact was made at all bump contacts, an increase (deterioration) in the contact resistance of the bumps was observed.

[Contact Reliability Confirmation Experiment 3] In this experiment, except that the thickness of the elastic body was fixed to one of 125 μm and the material was polyimide having tensile elastic moduli of 350 kg / mm ² and 1300 kg / mm ² , The contact reliability of the bumps was confirmed by the same method as in Experiment 1 above. As a result, with respect to the sample having a tensile modulus of elasticity of 350 kg / mm ² , all bumps were in contact with each other and the contact resistance was unchanged. On the other hand, in the case of the 1300 kg / mm ² sample, several points of poor contact occurred. However, there was no change in contact resistance for those that contacted.

[Contact Reliability Confirmation Experiment 4] In this experiment, as the elastic body, an example in which a fluorine-based resin is used, the tensile elastic modulus is 6
PTFE (polytetrafluoroethylene) of 0 kg / mm ² was used, and the thickness of each of the three types of samples was 4 μm and 1 μm.
The contact reliability of the bumps was confirmed in the same manner as in Experiment 1 except that the bump contact reliability was 3 mm. As a result, thickness 1
With respect to the mm sample, contact was made 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 contact resistance for those that contacted. Further, in the case of 3 mm, all bumps were able to make contact, but the contact resistance of the bumps increased (deteriorated).

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,
It is possible to make contact with bumps on the probe without leaving any contact with a contacted portion that is minute and has a high density, such as a bare chip LSI, and the contact reliability decreases over time. It's difficult. As a result, it is possible to provide a probe useful for process inspection of a small electronic component device product or a connection portion inside an external product.

[Brief description of drawings]

FIG. 1 is a schematic diagram partially showing a cross section of 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 sectional view schematically showing a specific mode of an elastic body.

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

[Explanation of symbols]

 A probe a substrate B contacting object b contacted portion 1 insulating film 2 bump contact 3 circuit pattern 4 elastic body 5 protective film

Claims (3)

[Claims] 1. At least a base body in which a plurality of bump contacts provided on at least one surface side of an insulating film and a circuit pattern provided on either surface of or inside the insulating film are electrically connected. An elastic body is provided at a position corresponding to the back surface of the bump contact, and the elastic body has a tensile elastic modulus 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 integrally with or detachably from the base body. 3. The probe according to claim 1, wherein the elastic body is made of a polyimide resin, a fluorine resin or a silicone resin.