JP3246841B2 - Probe structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-diced wafer on which semiconductor elements are formed, a bare die after dicing, or a pad or hemispherical solder ball formed on these pads. The present invention relates to a probe structure useful for measuring various electrical characteristics of a minute test object or a burn-in test performed at a high temperature, and particularly relates to a probe structure in which a contact portion with the test object is a bump.

[0002]

2. Description of the Related Art Conventionally, the inspection of various characteristics of an IC chip has been carried out by an I chip.
This was done after packaging C. For example, in a burn-in test, which is a characteristic test at a high temperature, a method of inserting an IC package into an IC socket provided on a printed wiring board and performing a test while applying a load voltage at a high temperature has been adopted. In recent years, the development of large-scale integrated circuits, such as chip-on-board and multi-chip modules, in which a large number of integrated circuits are combined at the stage of being formed on a wafer has been rapidly growing. It is required to perform it in a bare state before the package, that is, at the stage of an IC chip (die level).
As one method for performing a test at the die level, a plate-shaped or hemispherical solder bump is formed on a pad of an IC chip on which a circuit is formed, and the solder bump is formed on a printed wiring board. Then, a test is performed while applying a load voltage under a high temperature. In order to inspect the electrical characteristics of the minute object to be inspected as described above, a probe card has been developed. This has a contact portion (so-called bump) in contact with a contact target portion of a device under test on a flexible insulating substrate surface. (Japanese Unexamined Patent Publication No. 62-182
In such a probe card, it is necessary that the bumps have low contact resistance and have excellent corrosion resistance and abrasion resistance. For this reason, the outermost layer of the conventional bump
Gold having low contact resistance and excellent corrosion resistance, and hard gold having improved wear resistance by adding about 0.1% of nickel or cobalt to gold have been used.

[0003]

However, when gold or hard gold is used for the outermost layer of the bumps, these are easily deformed by contact with the electrode pad of the device under test, so that poor conduction and change in contact resistance are caused. However, the reliability as a probe for use in repeated inspection was low. Further, when a base metal is used as a base of the outermost layer, there is a problem that gold in the outermost layer is crushed to expose the base metal, and oxidation and corrosion occur from that portion. Also,
When the device under test is an IC, the material of the electrode pad is mainly aluminum. However, when there is a thermal history as in a burn-in test, the aluminum is transferred and adhered to the gold on the bump surface, diffused, and caused contact resistance. There was a problem that becomes high. Further, there is a problem that base metals such as Cu and Ni contained in soft gold diffuse to the surface at high temperatures and oxidize, thereby increasing contact resistance. Further, as described above, in a test method in which a plate-shaped or hemispherical solder bump is formed and used on an IC chip pad, after the test is completed, a temperature is applied to melt the solder bump solder. In order to remove the IC chip, the size, volume, shape, and the like of the bumps formed on the pads of the IC chip are varied, and it is necessary to form solder bumps again. Also, IC
Since the solder remains on the joints on the printed wiring board after peeling off, there is a problem that cleaning must be performed every time inspection is performed.

An object of the present invention is to solve the above-mentioned conventional problems and to maintain a low and stable contact resistance in an electrical test of a minute object to be inspected such as an IC or a semiconductor element, particularly in a burn-in test. However, in a test method in which a solder bump is formed and used, the solder component of the test object after the inspection does not adhere to the contact portion, in other words, the volume of the solder bump of the test object is reduced. Without happening,
Moreover, it is an object of the present invention to provide a probe structure capable of performing a highly reliable test with little deterioration from an initial contact state even when contact opening / closing with a test object is repeated.

[0005]

The above object is achieved by the following probe structure of the present invention. (1) A conductive contact portion is formed on one surface side of the insulating substrate, and a conductive circuit is formed on the other surface side of the insulating substrate,
The contact portion and the conductive circuit are conducted through a conduction path formed in a through hole in the thickness direction of the insulating substrate, and the contact portion is
Nickel, nickel-tin alloy, nickel-palladium
An alloy, or a deep layer made of a nickel alloy when the material of the conductive circuit is copper ; a middle layer provided on the deep layer and made of gold, palladium, indium, or platinum; and a middle layer. Rhodium, ruthenium, rhodium alloy, ruthenium alloy, rhodium-ruthenium alloy,
A probe structure having a surface layer made of a cobalt-tungsten alloy, chromium, an iron-tungsten alloy, or a chromium-molybdenum alloy. (2) The probe structure according to (1), wherein the deep layer material at the contact portion is nickel, the middle layer material is gold, and the surface layer material is rhodium. (3) The probe structure according to (1) or (2), wherein the thickness of the middle layer in the contact portion is 0.1 to 5 μm, and the thickness of the surface layer is 1 to 10 μm. (4) The probe structure according to any one of (1) to (3), wherein at least one of a deep layer, a middle layer, and a surface layer in the contact portion is formed by plating.

[0006]

In the probe structure of the present invention, as described above, the contact portion has three layers of a deep layer, a middle layer, and a surface layer. The operation of each layer and the operation of the entire structure are as follows. The deep layer serves as a conduction path for electric signals, as well as a known bump contact, and serves as a base of the contact portion or a core at the center to support the strength of the contact portion. The middle layer absorbs and relaxes the stress generated in the contact portion due to the contact pressure applied to the surface layer. Further, it is more preferable that the base layer of the surface layer has a function of making the surface layer and the deep layer adhere well to each other. The surface layer is a layer resistant to wear and damage. By having corrosion resistance and having the property of suppressing the transfer and diffusion of other metals from the test object, the contact resistance can be maintained at a low state, which is more preferable. Also, in a test method in which a solder bump is formed and used, by imparting touch resistance to the surface layer, the solder bump of the device under test is transferred and diffused to the contact portion with the bump of the probe. Is suppressed, and the volume of the solder bump of the test object after the inspection is hardly reduced, which is preferable.
In addition, the combination of these three layers compensates for the disadvantages of the materials of the respective layers, and forms a contact portion that is less deteriorated by repeated contact opening and closing.

[0007]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a sectional view showing an embodiment of the probe structure of the present invention. As shown in the figure, in the probe structure, a contact portion 2 is formed on one surface side 1a of an insulating substrate 1, and a conductive circuit 3 is formed on the other surface side 1b of the insulating substrate 1, The contact portion 2 is electrically connected to the conductive circuit 3 through a conduction path 5 formed in a through hole 4 provided in a thickness direction of the insulating substrate 1. No. 2 has a deep layer 2c, a middle layer 2b, and a surface layer 2a whose hardness and properties are described below. (However, this figure is a diagram showing an example in which the contact portion 2 and the conduction path 5 are integrally formed of the same material.)

The material of the insulating substrate is not particularly limited as long as it has an insulating property. However, a material having flexibility as well as an insulating property is preferable, and a polyester resin, an epoxy resin, a urethane resin, a polystyrene resin is preferable. Resin, polyethylene resin, polyamide resin, polyimide resin, acrylonitrile-butadiene-styrene (AB
S) Thermosetting resins or thermoplastic resins such as copolymer resins, polycarbonate resins, silicone resins, and fluorine resins. Among these, polyimide resins are particularly preferably used because they are excellent in heat resistance and mechanical strength, and can be matched with the coefficient of linear expansion of the test object. The thickness of the insulating substrate is not particularly limited, but is preferably 2 to 50 in order to have sufficient mechanical strength and flexibility.
The thickness is set to 0 μm, preferably 5 to 150 μm, more preferably 8 to 150 μm, and most preferably 10 to 150 μm.

The conductive circuit includes a contact portion, a coil, a resistor, and a circuit pattern formed of a conductor / semiconductor.
Includes elements such as capacitors that constitute a circuit. The material of the conductive circuit is not particularly limited as long as it has conductivity irrespective of conductor or semiconductor, but a known good conductor metal is preferable. For example, single metals such as gold, silver, copper, platinum, lead, tin, nickel, cobalt, indium, rhodium, chromium, tungsten, ruthenium, or various alloys containing these as components, for example, solder, nickel-tin, gold −
Cobalt and the like. The thickness of the conductive circuit is not particularly limited.
μm or more is preferable, and from the viewpoint of workability by chemical etching or the like, 200 μm or less is preferable. Within these ranges, it is particularly preferable to set the thickness to 5 to 50 μm.

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), or a method of removing another conductor portion so as to leave the target circuit pattern is used. Formation method (subtractive method). The former method includes drawing a circuit pattern using a film forming method such as sputtering, various kinds of vapor deposition, and various kinds of plating. In the latter method, a conductor layer is formed on an insulating substrate, a resist layer is formed on the conductor layer so as to cover only a desired circuit pattern shape, and then the exposed conductor layer is etched. Then, a method of obtaining a desired circuit pattern can be mentioned.

The through hole serves as a conductive path between the contact portion and the conductive circuit, and the hole diameter is made as large as possible and the pitch between the holes is made as small as possible within a range where adjacent through holes are not connected to each other. It is preferable to increase the number of the through holes per contact in order to reduce the electric resistance as a conduction path. The diameter of the through-hole is 5 to 200 μm, preferably 8 to 200 μm.
About 50 μm is good. Examples of the method of forming the through hole include a mechanical perforation method such as punching, plasma processing, laser processing, photolithography processing, and chemical etching using a resist or the like having different chemical resistance from the insulating substrate. Laser processing is a method that allows fine processing of the through-hole with an arbitrary hole diameter and an inter-hole pitch, and can cope with a fine pitch of the contact portion. Above all, perforation by irradiation with an excimer laser in which the number of pulses or the amount of energy is controlled is preferably performed with high accuracy. In addition, as shown in FIG. 2, by forming the through-hole not only perpendicularly to the insulating substrate surface but also at a predetermined angle to the insulating substrate surface, Is decomposed, and damage to the conductor portion of the test object can be prevented.

The conduction path may be any path formed in the through-hole and capable of connecting the contact portion and the conductive circuit, and may be formed by filling the through-hole with a conductive substance, such as through-hole plating. And a layer formed by forming a conductive material layer all around the wall surface of the through hole. As a method of forming the conduction path,
Method of mechanically inserting conductive material into through hole, CVD
Examples of the method include a film forming method such as a plating method, and a plating method such as electrolytic plating and electroless plating. A method using electrolytic plating using a conductive circuit as an electrode is simple and preferable.

The contact portion is a conductor portion provided on the surface of the insulating substrate for the purpose of electrical contact and connection with the device under test. Regarding the aspect as the contact portion as a whole, regardless of the presence or absence of protrusion from the insulating substrate surface, and the shape of the contact surface on the contact portion upper surface is convex, planar,
Any of concave shapes may be used. Therefore, the cross-sectional shape when the contact portion is cut along a plane perpendicular or parallel to the substrate surface is not limited, and all polygons, circles, ellipses,
Depending on the combination of these cross-sectional shapes, the shape of the contact portion may be the end or side surface of a polygonal or cylindrical column, a cone (a truncated cone) / a pyramid (a trapezoid), or a part of a sphere. All three-dimensional shapes are possible. Thereby, the contact with the object to be inspected is a point contact, a line contact, a surface contact, or the like. Although the height of the contact portion from the surface of the insulating substrate is not particularly limited, it is preferably about 0.1 μm to several hundred μm for a minute inspection object such as an IC.

The contact portion has three layers: a deep layer, a middle layer, and a surface layer. Further, the deep layer and the conduction path may be integrally formed of the same material. The wood charge depth layer are those inexpensive conductor metal used in bump publicly known are preferred, nickel, nickel-tin alloy, nickel-palladium alloy and the like. Also, the deep layer and the conduction path
In many cases, they are integrally formed of the same material and connected to a conductive circuit. In such a case, the material forming the deep layer is:
It is preferable that the material be crystallographically compatible with the material forming the conductive circuit, have good adhesion, and hardly diffuse. For example, when the material of the conductive circuit is copper, nickel or a nickel alloy is a preferable combination of the deep layer material. Such materials have a hardness of 3
It is a conductor of not less than 00Hk and not more than 700Hk. However,
Hk is a unit of the Knoop hardness number (Knoop hardness). Hard
For materials with a temperature of less than 300Hk, the contact part contacts the contact object
Easily deformed when pressure is applied, and a hardness of 70
If it exceeds 0Hk, cracks are likely to occur. Deep
A more preferable range of the hardness is 450 to 600 Hk.
And particularly preferably 550 to 600 Hk. The method of adjusting the hardness is preferably adjusted by alloying or adding an organic substance from the viewpoint that the insulating substrate is not damaged by heat.

[0015] As timber fees middle layer, for example, gold, palladium, silver, indium, platinum and the like. In addition, a metal having corrosion resistance even when exposed to the surface, having excellent adhesion to the deep layer and the surface layer, is more preferable.
If the surface layer is rhodium, gold is the most preferred material for the middle layer. Such materials have a hardness of 10 Hk or less.
Above, it is less than 300Hk. Material is hardness less than 10Hk
Easy to deform, and cushioning property at 300Hk or more
poor. A more preferable range of the hardness of the middle layer is 50 to 2
00Hk, particularly preferably 50-100 Hk.
You. The thickness of the middle layer is 0.1-5 μm, preferably 0.5-
3 μm, particularly preferably 0.5 to 1 μm. 0.1
If it is less than μm, the cushion effect is weak, and if it is more than 5 μm, the amount of deformation when pressure is applied becomes large, so that the surface metal is easily cracked.

Examples of the material of the surface layer include hard metals such as rhodium, ruthenium, cobalt-tungsten alloy, chromium, iron-tungsten alloy, and chromium-molybdenum alloy. In particular, a material having corrosion resistance and a property as a barrier for preventing diffusion of a metal transferred from a contact object is more preferable, and examples thereof include noble metals such as rhodium and ruthenium. When using the precious metal in the surface layer, the noble metal is a single metal, have good either alloy.
In order to suppress an increase in contact resistance due to the base metal being diffused and oxidized to the surface, an increase in internal stress due to organic impurities, and the occurrence of cracks, it is preferable that 99% or more is a noble metal. In the case of an alloy, a combination of a noble metal having corrosion resistance and hardly diffusing is preferable, and a combination of rhodium and ruthenium is exemplified. Such a material has a hardness of 700 Hk or more and 1200 Hk or less.
If the hardness of the material is less than 700 Hk, the surface layer is easily damaged when the test object comes into contact with the conductor.
If the ratio exceeds the range, cracks are likely to occur. A more preferable range of the hardness of the surface layer is 800 to 1100 Hk,
Particularly preferably, it is 900 to 1000 Hk. The thickness of the surface layer is 1 to 10 μm, preferably 2 to 5 μm, and particularly preferably 2 to 3 μm. When the thickness of the surface layer is less than 1 μm, pinholes are easily generated, and when it is more than 10 μm, cracks are easily generated.

The method of forming the contact portion, that is, the method of laminating each layer includes a pressure welding method using a metal foil for each layer, a film forming method such as ion plating, ion sputtering, and CVD method, and a method such as electrolytic plating and electroless plating. Examples include a plating method. Among these forming methods, in particular, a method of electrolytic plating using a conductive path as an electrode is preferable because the metal purity, hardness, and external dimensions can be controlled, and variations can be controlled with little quality. When the contact portion is formed by a plating method, it is preferable to perform a wettability improving treatment such as methanol replacement or surface modification by plasma in order to reliably fill the through hole with the plating solution. Further, when forming the metal of the core, by supplying a current linearly according to the surface area to be plated and maintaining a constant current density, the internal stress of the core can be made uniform and cracks can be prevented. . In particular, when the material of the surface layer is the above-mentioned noble metal and is formed by plating, by rotating and oscillating the object to be plated in the plating solution, the flow direction and force of the plating solution with respect to the object to be plated become uniform, and The deposition efficiency of the surface layer at the contact portion becomes uniform, and as a result, the thickness of the surface layer becomes uniform. Further, in the case of rhodium plating, in order to suppress the occurrence of cracks, it is preferable to prevent impurities from being mixed into the plating solution and keep the rhodium deposition purity at 99% or more.

Further, depending on another inspection object, an example having a plurality of minute bumps 2d on the deep layer 2c, as schematically shown in FIG. 3, can be cited as an example of a preferable shape of the contact portion. Deep layer 2c on which the minute bumps 2d are formed
By forming the middle layer 2b and the surface layer 2a thereon and making the surface of the contact portion uneven, the insulating layer such as an oxide layer or a foreign substance formed on the conductor surface of the device under test is broken, and the reliability of the contact is improved. Is improved. As an example of a method for forming the minute bumps 2d, after forming a deep layer, a metal powder serving as a core of the minute bumps is dispersed in a plating bath and subjected to electrolytic plating. The particle diameter of the metal powder is 1/1 of the bump diameter.
00 to 1/10 is good. Further, by using a metal powder having magnetism such as cobalt and applying a magnetic field of about 1 to 15 kilogauss in a plating bath and performing electrolytic plating, the metal powder can be uniformly applied to the surface of the bump metal 1.

Although the probe structure of the present invention alone has a function as a probe, a high-performance probe card is formed by bonding with a multilayer wiring board as described below.
FIG. 4 is a diagram schematically showing an example of the structure of the probe card. As shown in the figure, the probe card is obtained by mechanically and electrically joining a probe structure A of the present invention and a multilayer wiring board B, and the probe structure A
The conductive circuit 3 of the probe structure A and the conductive circuit 7 of the multilayer wiring board B are joined via an elastic body 6 on the multilayer wiring board B so that a stroke operation can be performed on the multilayer wiring board B. , So as not to hinder the stroke operation. In the figure, the conductive circuit 3 and the conductive circuit 7
When the conductive circuit 3 is extended, it protrudes from the end of the insulating substrate, bends smoothly to the surface of the multilayer wiring board B, and is joined to the terminal 8 provided on the surface of the multilayer wiring board B. It is done by that. The terminal 8 has a probe structure A
With the same structure as that of the conductive path, the conductive circuit 7 is electrically connected to the conductive circuit 7 provided in the lower layer of the multilayer wiring board B and is connected to an external connection device or the like.

The multilayer wiring board is obtained by alternately stacking conductive circuits and insulating layers, and connecting circuits of different layers by a structure similar to the conductive path of the probe structure of the present invention. The multilayer wiring board is a multi-chip module (MCM)
It can be manufactured by applying the technology of the substrate, and mainly includes three types of MCM-D, C, and L.

By inserting a resistor (not shown) in series in the conductive circuit of the multilayer wiring board, a load voltage can be applied to the device under test, and furthermore, an overcurrent caused by a short circuit in the circuit of the device under test can be reduced. Can be prevented. Also, noise can be reduced by connecting a capacitor (not shown) in parallel with the resistor.

The elastic body may be any as long as it can absorb an error in the distance between the probe structure and the test object when the probe structure is brought into contact with the test object. Silicone rubber, fluorine rubber, urethane A polymer elastic body such as rubber is preferably used. Examples of the method for forming the elastic body on the multilayer wiring board include a method in which a sheet-like elastic body is cut and attached, a method in which the elastic body is directly formed by a screen printing method, a photolithographic method, and the like. The thickness of the elastic body should be adjusted so that when a fine conductor such as an IC pad is to be contacted, the variation in the height of the terminal of the device under test is absorbed and the contact between the conductor of the device under test and the probe structure is made. 5 to 1000 μm, preferably 2 μm, in order to make the electrical connection with the part more secure.
It is preferably from 0 to 500 μm.

The external connection device is not only an independent inspection device such as a tester, but also, for example, a device used for impedance matching between a device under test and circuit wiring, and a product connected in a later process. Other I like
C may be used.

Hereinafter, a more specific production example of the probe structure of the present invention will be described. Production Example 1 [Formation of Insulating Substrate and Conductive Circuit] The thickness of the polyimide precursor solution after drying was 25 μm on a 35 μm thick copper foil.
And dried and cured to produce a two-layer film of a copper foil and a polyimide film as an insulating substrate. Next, after forming a resist layer in a circuit pattern on the surface of the copper foil, a conductive circuit having a desired circuit pattern was formed by using a photo process.

[Formation of Conductive Paths and Deep Layers] KrF excimer laser light having an oscillation wavelength of 248 nm is irradiated through a mask perpendicularly to the surface of the polyimide film, and dry-etched at a position directly behind the conductive circuit of the polyimide film. A fine through hole of φ60 μm was formed in the polyimide film, and the conductive circuit was exposed in the through hole.
Such through holes are formed at a pitch of 200 μm and 5 holes / mm ²
In an area of 8 cm ² . Next, a resist was applied to the surface side of the conductive circuit and immersed in a chemical polishing solution at 50 ° C. for 2 minutes. After washing with water, the conductive circuit is connected to the negative electrode, immersed in a 60 ° C. watt bath, and nickel is deposited in the through hole using the copper foil of the conductive circuit exposed in the through hole as the negative electrode.・ Grow and fill to form a conductive path,
The contact layer was grown to a depth of 5 μm from the surface of the polyimide film to form a deep layer.

[Formation of Middle Layer and Surface Layer, Completion of Probe Structure] Strike plating of a gold cyanide plating bath was performed at room temperature at 0.03 μm, and then a 0.5 μm gold layer was formed at 65 ° C. in a gold cyanide plating bath. And the middle layer. 50 ° C
In a rhodium sulfate plating bath, to form a 2 μm rhodium film, which was used as a surface layer. Finally, the resist layer applied on the surface side of the conductive circuit was peeled off to obtain the probe structure of the present invention.

[Evaluation Test 1] In order to check the contact resistance value of the probe structure obtained above, the contact portion was actually brought into contact with the aluminum electrode of the IC, and an electric resistance test was performed with a tester. Apply a contact pressure of 5 g per contact point,
When a current of 100 mA was passed, a low resistance value of 500 mΩ was observed. Further, when the change in the contact resistance value due to the repeated contact opening and closing in the burn-in test was examined, the resistance value was as low as 500 ± 100 mΩ even when the electric resistance test was repeated 20 cycles in an atmosphere of 150 ° C. It was confirmed that. After the above-described repetitive test, the surface of the contact portion was observed. As a result, scratches, cracks, and corrosion were not found on rhodium on the surface layer, and no transfer or diffusion of the aluminum electrode of the IC was observed.

Manufacturing Example 2 In order to cope with a test method in which solder bumps are formed and used, a probe structure was manufactured by exactly the same processing steps as in Manufacturing Example 1 except for the dimensions of the following portions. [Formation of insulating substrate and conductive circuit] The thickness of the copper foil is 18μ.
m, and the thickness of the polyimide precursor solution after drying was 13 μm. [Formation of Conduction Path and Deep Layer] The inner diameter of the fine through-hole for the polyimide film by KrF excimer laser light is φ5.
0 μm and pitch 250 μm. The deep layer of the contact portion was grown to a position protruding 8 μm from the polyimide film surface. [Formation of Middle Layer and Surface Layer, Completion of Probe Structure] The thickness of the gold in the middle layer was 1 μm.

[Evaluation Test 2] To check the contact resistance value of the probe structure obtained in Production Example 2, copper (35 μm) was used.
15 μm of solder plating was applied to the copper surface of a two-layer base material composed of / polyimide (25 μm), and the bump of the probe of the present invention was brought into contact with the plating, and an electric resistance test was performed with a tester. When a contact pressure of 10 g was applied per contact point and a current of 100 mA was passed, a low resistance value of 20 mΩ was observed. In a test for examining a change in contact resistance value in a burn-in test, the test was conducted at 150 ° C. for 1000 hours.
Under the conditions described above, it was confirmed that the resistance value was in a low range of 20 ± 4 mΩ. Observation of the surface of the contact portion after the above-described repetitive test revealed that rhodium on the surface was not transferred or adhered by diffusion of solder.

The object to be inspected by the probe structure of the present invention for contact and connection is a semiconductor element, an aggregate of semiconductor elements (a silicon wafer before dicing, a silicon chip after dicing, etc.), an apparatus comprising a semiconductor element, It has fine conductor parts such as a circuit board for mounting the device, a circuit board for LCD, etc., and solder (an alloy mainly composed of tin, lead and two metals) bumps on these conductor parts. It is what you have. The conductor of the test object is
It means all conductors that make up the circuit of the device under test, such as various elements, their electrodes, and any locations on the circuit pattern.Especially, in actual use, a minute device under test is electrically connected to other conductors. Terminals, pads, lands, and the like, which are intended to make contact and connection with each other, are important portions as contact portions.

[0031]

According to the probe structure of the present invention, the hard metal used for the surface layer of the contact portion, particularly the hard noble metal,
It is possible to prevent a base metal such as aluminum used for the conductor portion of the test object from being transferred to the contact portion and to be diffused, to be resistant to corrosion and to maintain a low contact resistance. In addition, by using a hard and corrosion-resistant noble metal for the surface layer of the contact part, in the case of a solder bump of the device to be inspected, the solder can be prevented from being transferred to the contact part and diffused, and a low resistance value is maintained. it can.
In addition, the soft metal used for the intermediate layer, which is the surface base adhesion layer, relieves stress caused by contact with the object to be inspected, thereby suppressing damage such as cracks. Therefore, I
C, the electrical test of a minute test object such as a semiconductor element, especially the repeated opening and closing of the contact with the test object in the burn-in test, there is little deterioration from the initial contact state, high reliability and stability. Electrical test can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a probe structure of the present invention.

FIG. 2 is a cross-sectional view schematically showing one example of a mode of a through hole in a probe structure of the present invention.

FIG. 3 is a cross-sectional view schematically showing one example of an aspect of a contact portion in the probe structure of the present invention.

FIG. 4 is a diagram schematically illustrating an example of a structure of a probe card including a probe structure of the present invention and a multilayer wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Contact part 2a Surface layer 2b Middle layer 2c Deep layer 3 Conductive circuit 4 Through hole 5 Conduction path

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-286592 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/66 G01R 1/073 G01R 31 / 26 H01H 1/00

Claims (4)

(57) [Claims] 1. A conductive contact portion is formed on one surface of an insulating substrate, a conductive circuit is formed on the other surface of the insulating substrate, and the contact portion and the conductive circuit are insulated from each other. Conduction is performed through a conduction path formed in a through hole in the thickness direction of the substrate, and the contact portion includes a deep layer, an intermediate layer provided on the deep layer,
And a surface layer provided on the layer, the material of the deep layer, nickel, nickel-tin alloy, nickel-palladium alloy, or a nickel alloy, before
The nickel alloy is only available when the material of the conductive circuit is copper.
The material of the middle layer is gold, palladium, indium or platinum , and the material of the surface layer is rhodium, ruthenium, rhodium alloy, ruthenium alloy, rhodium-ruthenium alloy, cobalt-tungsten alloy A probe structure characterized by being made of chromium, iron-tungsten alloy, or chromium-molybdenum alloy. 2. A method according to claim 1, wherein the deep layer material at the contact portion is nickel,
The material of the middle layer is gold, and the material of the surface layer is rhodium.
The described probe structure. 3. The thickness of the middle layer in the contact portion is 0.1 to 5
The probe structure according to claim 1 or 2, wherein the thickness of the surface layer is 1 to 10 m. 4. The probe structure according to claim 1, wherein at least one of the deep layer, the middle layer, and the surface layer in the contact portion is formed by plating.