JP3641609B2 - Method for manufacturing a pencil type probe for a probe card - Google Patents

Description

【００２５】
なお、本発明は、垂直型プローブカード用であって湾曲部を有するプローブに限定されず、垂直型プローブカード用であって湾曲部がなくて真っ直ぐに下方に伸びる直線状のプローブにも適用可能である。また、本発明はカンチレバー型プローブカード用であって先端部が下向きに折り曲げられたプローブにも適用可能である。
【００２６】
【発明の効果】
以上述べたところから明らかのように、本発明によれば、タングステンプローブ先端部に導電性と耐酸化性を有する貴金属合金を機械的、電気的に信頼性の高い接合を完成せしめる。こうすれば、タングステンの剛性、弾力性を有し、かつ接触性能の良い貴金属合金製の針先を有する鉛筆型プローブが得られる。この鉛筆型プローブにより集積回路の微細化が進んで、電極間のピッチ寸法が小さくなっても充分対応が可能となり、しかも、再クリーニングが少なくなることで、集積回路の検査処理能力の向上に寄与する。また、この鉛筆型プローブは直径が４０乃至６５μｍと細くなっても性能が維持できるので、半導体ウェハーの検査のみならず、ピッチ寸法がより小さい液晶用ドライバーの検査等にも対応できる。
【図面の簡単な説明】
【図１】タングステン線に連続した孔２個を穿孔した状態を示す。
【図２】タングステン線の孔中に貴金属合金を溶解して埋め込んだ鉛筆型プローブ先端部のＡ−Ａ断面図である。
【図３】タングステン線の端部を研磨し貴金属合金を先鋭化した状態を示す。
【図４】タングステン線に連続した孔列を穿孔した状態を示す。
【図５】貴金属合金線を矢印の方向から拡開した孔列へ挿入する状態を示す。
【図６】タングステン線の拡開した孔列の開放部を閉じて、貴金属合金線を挟み込んだ状態を示す。
【図７】タングステン線の端部の貴金属合金部を研磨し先鋭化した状態を示す。
【図８】垂直型プローブカードの構成を示す断面図である。
【図９】プローブカードに用いられる湾曲部を有するプローブの図である。
【図１０】垂直型プローブカードに用いられるプローブの外観形状を示す図である。
【符号の説明】
１００：タングステン線 ２００：タングステン線に開けられた孔
２０１：タングステン線の孔列の開放端部 ３００：貴金属合金
１：プローブ １ａ：湾曲部 ２：ガイド部 ３：基板
４：ウェハ載置台 ５：ウェハ ５１：ＩＣチップ ５１ａ：電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a pencil-type probe for a probe card used in a probe card for inspecting the electrical characteristics of an IC chip and the pencil-type probe.
[0002]
[Prior art]
An apparatus called a probe card is used when inspecting the electrical characteristics of an IC chip formed with a semiconductor device. FIG. 8 is a cross-sectional view showing the configuration of the vertical probe card. As shown in the figure, the vertical probe card has a plurality of probe card probes (hereinafter simply referred to as probes) 1 having a curved portion 1a and forming a needle shape, and these probes 1 are suspended and fixed. The guide portion 2 and the substrate 3 each having a wiring pattern formed by soldering the probe rear end for each probe 1 are formed.
[0003]
Reference numeral 4 denotes a wafer mounting table. On the wafer mounting table 4, a wafer 5 on which a plurality of IC chips 51 to be inspected are formed is mounted. Reference numeral 51 a denotes an electrode formed on the surface of the IC chip 51. The vertical probe card is such that the tip of the probe 1 is brought into perpendicular contact with the electrode 51a of the IC chip 51, and the electrode of the IC chip 51 is raised by raising the wafer mounting table 4 in the direction of the probe 1. 51a and the tip of the probe 1 come into contact with each other.
[0004]
Here, the electrode 51a of the IC chip 51 is formed of an aluminum-copper alloy film containing aluminum and copper, or an aluminum film. On the surface of the electrode 51a, an oxide film made of thin aluminum oxide is formed. . Since this oxide film is an insulator, the tip of the probe 1 cannot be electrically connected to the aluminum-copper alloy film simply by bringing the tip of the probe 1 into contact with the surface of the electrode 51a.
[0005]
Therefore, when the tip of the probe 1 is brought into contact with the electrode 51a, and then the IC chip 51 is further raised in the direction of the probe 1, that is, overdrive is applied, the probe 1 is bent as shown in FIG. As the portion 1a is elastically deformed and bent, the probe tip presses the electrode 51a with a predetermined contact pressure (needle pressure). Thereby, the oxide film is broken from the surface of the electrode 51a at the contact point between the probe 1 and the electrode 51a, and the tip of the probe 1 and the aluminum-copper alloy film of the electrode 51a can be in direct contact. The contact pressure (g) increases in proportion to the value of the overdrive amount (μm).
[0006]
FIG. 10 is an explanatory view showing the external shape of a probe used in a vertical probe card. The dimensions of the probe will be described. Diameter (outer diameter) D: 80 μm, tip length L1: 450 μm, cutting-edge diameter d: 25-30 μm, curved portion length L2: about 2 mm. The probe having a diameter D of 80 μm is used for a vertical probe card for inspecting an IC chip having a pitch dimension between electrodes of 120 μm. Conventionally, a hard and highly resilient metal such as tungsten or beryllium copper is used for a probe in a wafer test of an integrated circuit. In particular, tungsten is often used because thin wires having excellent wear resistance and a diameter of several tens of microns can be obtained at a relatively low price, and more than 90% of current probe cards use tungsten probes. However, tungsten has a relatively high electrical resistance as a metal, and if the contact of thousands of contacts as an integrated circuit is repeated with an integrated circuit, the contact resistance of the probe tip increases, and eventually it becomes untestable. . As a means of improving the contact performance of such a tungsten probe, it is conceivable to use a metal that is difficult to oxidize, such as gold or platinum, but it is expensive and soft compared to tungsten, so it wears quickly. Resulting in. Further, the strength, elasticity, etc. as a probe are considerably smaller than that of tungsten, and a thick wire must be used to give a predetermined contact pressure, which makes it difficult to meet the demand for miniaturization.
[0007]
[Problems to be solved by the invention]
Tungsten has very good performance as a probe, but the disadvantage is that the surface is easily oxidized and the conductivity of the probe tip is reduced. Usually, in addition to the inspection temperature in the burn-in test being 85 ° C. or 150 ° C., the current flows through the electrodes of the integrated circuit made of aluminum or aluminum-copper alloy thousands of times and tens of thousands of contacts. As a result of the heat generated by frictional heat or contact resistance, the temperature of the probe tip rises and is oxidized, and also combines with aluminum or aluminum alloy deposited on the electrodes of the integrated circuit to generate and adhere aluminum oxide. In such a state, the electrical resistance of the probe surface increases, which hinders the wafer test, and the tip must be polished and refreshed. Normally, the polishing operation of the probe tip is performed at a rate of once every several thousand contacts, and this polishing operation becomes an obstacle in the test operation that is performed fully automatically, which is a problem.
[0008]
As a method for improving the deterioration of such contact performance, the present applicant has disclosed the technique of Japanese Patent Application Laid-Open No. 11-38039, and gold, platinum, rhodium which are non-oxidizing metals on the tungsten probe surface by a metallization method. A film of one non-oxidizing metal selected from palladium, iridium is formed, and then heated in a non-oxidizing atmosphere or vacuum to diffuse the non-oxidizing metal film into tungsten. Thus, a tungsten probe having a diameter of 250 μm and a gold diffusion layer thickness of 20 μm is obtained. In a situation where the electrode pitch of the recent integrated circuit is reduced, the wire diameter is large (80 μm) and the thickness of the non-oxide film is not satisfactory.
[0009]
Further, as one method for improving the contact performance, there is a method of making a probe with an alloy mainly composed of noble metals. For example, there is an alloy called Parina 7 in the United States, which is an alloy containing palladium, silver, platinum, gold, etc., which becomes hard due to age hardening and can be used as a probe. However, since the properties such as tensile strength and elasticity (Young's modulus) are inferior to those of tungsten, the thickness of the diameter of 100 μm is the limit, and the characteristics of the probe are maintained with the thinner line to cope with the miniaturization of the integrated circuit. It is difficult. As a countermeasure, a method for adhering the alloy wire only to the tip of the tungsten wire has been proposed, but it is extremely difficult to weld a dissimilar metal to tungsten, and the reliability of welding is poor.
[0010]
Furthermore, with the recent miniaturization of integrated circuits, the electrode pitch of integrated circuits is becoming from 120 μm to 100 μm, and accordingly, the probe diameter is required to be 80 μm to 65 μm. In view of the above circumstances, the present invention has been completed as a result of various inventions and trials. The probe can cope with a decrease in the pitch dimension between electrodes of an IC chip due to the progress of miniaturization of integrated circuits. A method for manufacturing a pencil-type probe for a card and the pencil-type probe are provided.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that the inner diameter of the wire core by a microfabrication laser is within a range of 2-3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 40-150 μm. After continuously penetrating holes of 20 to 100 μm so that the holes overlap, non-oxidizing noble metal or noble metal alloy having a melting temperature lower than that of tungsten is melt-embedded and fixed in the elongated hole row, and the end portions are fixed. A method for producing a pencil-type probe for a probe card, characterized by sharpening by polishing.
[0012]
According to the second aspect of the present invention, a hole having an inner diameter of 20 to 100 μm is overlapped on a wire core by a microfabrication laser within a range of 2 to 3 mm in the axial direction from an end of a tungsten wire or tungsten alloy wire having a diameter of 40 to 150 μm. After continuously penetrating in this manner, after expanding from the open end of the hole row, after inserting a non-oxidizing noble metal wire or noble metal alloy wire into the elongated widened hole row, sandwiching and gripping, A method of manufacturing a pencil-type probe for a probe card, characterized in that an end portion is polished and sharpened.
[0013]
According to the invention of claim 3, a plurality of adjacent holes having an inner diameter of 50 to 100 μm are used within a range of 2 to 3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 80 to 150 μm, using a micromachining drill. was Nuki穿, then, after the perforation of the wall in the axial direction of the line to melt removed by micromachining laser provided an elongated hole row of continuous, elongated into the hole row, less than tungsten melting temperature non-oxidizing fixed and embedded melting noble metal or noble metal alloy, a manufacturing method of a probe card for pencil probe characterized that you sharpened noble metal or noble metal alloy portion by polishing the end portion. Further, the invention of claim 4, in the range of 2~3mm from the end of the tungsten wire or a tungsten alloy wire with a diameter of 80~150μm axially, using a fine processing for drill, a plurality of inner diameter 50~100μm After penetrating adjacent holes, the wall of the hole in the axial direction of the line is melted and removed by a microfabrication laser to form a continuous elongated hole array, and then expanded from the open end of the hole array. For a probe card characterized by inserting a non-oxidizing noble metal or noble metal alloy into the widened hole array, sandwiching and gripping, and then polishing the end portion to sharpen the noble metal or noble metal alloy portion It is a manufacturing method of a pencil type probe.
[0014]
Since the tungsten wire or the tungsten alloy wire has high tensile strength and elasticity, the minimum wire diameter of the probe for obtaining an appropriate contact pressure can be 40 μm. The tungsten alloy wire here includes a W-3 mass% Re alloy containing 3 mass% rhenium. However, tungsten or a tungsten alloy (hereinafter referred to as tungsten) is easily oxidized, and the electrical contact performance deteriorates. To improve this, no noble metal or noble metal alloy that does not oxidize even at the inspection temperature and has excellent conductivity. The needle tip is desirable. Claims 1 to 3 are manufacturing methods for attaching a noble metal or noble metal alloy needle tip to a tungsten wire.
[0015]
The gist is to use a laser that can be finely processed with the same wavelength of light. A fine hole is penetrated into the tungsten wire by the energy of this light beam. Here, a non-oxidizing noble metal or noble metal alloy wire having a melting temperature lower than that of tungsten is melted and embedded, or a non-oxidizing noble metal or noble metal alloy wire is sandwiched and held to join them together. The noble metal referred to here is a kind of metal selected from gold, platinum, silver, rhodium, palladium, and iridium, and the noble metal alloy refers to an alloy made of two or more kinds of metals selected from the aforementioned noble metal group.
[0017]
The pencil type probe manufactured by these methods has a tip of a noble metal or a noble metal alloy (hereinafter referred to as a noble metal alloy) at the tip of a tungsten wire having a diameter of 40 to 150 μm. The portion of the tungsten wire is fixed or held in a continuous hole array or an elliptical hole formed extending in the axial direction. The pencil-type probe manufactured by the method of the present invention is made of tungsten wire, so the tungsten has a hard and elastic characteristic (high Young's modulus), and even if the probe diameter is as thin as 40 to 150 μm. The contact pressure can be sufficiently obtained with a predetermined overdrive amount. Moreover, when the number of contacts with the tungsten needle tip increases, the contact performance deteriorates due to oxidation, and the tip must be polished and refreshed. However, the pencil-type probe of the present invention is a noble metal with a non-oxidizing tip. Since it is an alloy needle tip, the contact performance does not deteriorate even if the number of times of contact increases. Further, the bonding of the noble metal alloy part fixed or held in the tungsten wire according to the method of the present invention has sufficient strength and conductivity, so that the performance as a probe as a whole can be sufficiently exhibited.
[0018]
In the pencil type probe manufactured by these methods , the outermost surface may be plated with gold. In the case where the outermost surface is plated with gold, it is possible to avoid an increase in electrical resistance due to the skin effect when a high-frequency signal is passed through the probe. In addition, after performing the grinding | polishing process which forms a front-end | tip shape, and the bending process which forms a curved part, gold plating is given. The appropriate thickness of the gold plating is 0.2 to 1.0 μm.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention are described below.
The present invention mechanically joins dissimilar metals that are difficult to join. By drilling a hole with an inner diameter of 20 to 100 μm, which could not be achieved by the conventional technology, by fine processing, noble metal is put inside the hole. It is intended to increase the reliability of mechanical and electrical joining at the joint between the melt filling and the noble metal portion and the tungsten portion. This will be described in detail below with reference to the drawings. FIG. 1 shows a state in which two holes 200 having an inner diameter of 30 μm are formed in a tungsten wire 100 having a diameter of 65 μm by laser processing. The spot of the laser beam is about 10 μm, and the light beam is rotated by a mirror to create a hole 200 having an inner diameter of 30 μm. Normally, when such laser processing is performed, the outlet of the through-hole 200 is about 20 μm, and becomes a conical hole. . When a noble metal alloy wire is placed on this hole and the laser beam is irradiated in an argon or nitrogen atmosphere so that the temperature of the noble metal alloy wire does not melt but the noble metal alloy wire melts, the noble metal alloy 300 melts and enters the inside of the hole 200. Enter and adhere to the hole wall of tungsten wire. FIG. 2 is a cross-sectional view of this state seen from the AA direction. As shown in FIG. 2, a state in which the noble metal alloy 300 fills up the hole 200 and rises slightly may be a point of fixing to the tungsten wire. . After that, if the tip is polished by a conventional method to form a tip exposed from the noble metal alloy portion 300 having the most advanced diameter of 25 μm, the pencil type for the probe card of the present invention having a highly reliable dissimilar metal joint Obtain the tip of the probe. FIG. 3 shows this state. Since this joining portion has a large joining area of the noble metal alloy 300 and is embraced by the wall of the tungsten wire 100, it is strongly held mechanically.
[0020]
In the second method, as shown in FIG. 4, a plurality of adjacent through holes 200 having an inner diameter of 50 to 100 μm are formed on a tungsten wire 100 having a diameter of 80 to 150 μm using a drill for fine processing (50 to 100 μmφ). Open. Thereafter, the wall of the perforation 200 in the axial direction of the tungsten wire 100 is melted and removed by a laser for fine processing to provide a continuous hole array. The open end 201 of the hole row is pushed out with forceps for fine processing, and the noble metal alloy wire 300 is inserted therein. This state is shown in FIG. Further, when the widened hole 200 is sandwiched between fine processing pliers and returned to the original position, a gripping portion in which the noble metal alloy wire 300 is sandwiched as shown in FIG. 6 is obtained. At this time, a part of the surplus noble metal alloy wire 300 is plastically deformed to perform strong bonding so that it protrudes in the axial direction of the hole 200, so that this bonding also exhibits highly reliable characteristics. However, in this operation, since the noble metal alloy wire 300 is mechanically inserted into the tungsten wire 100, the length of the hole row 200 needs to be larger than that of the first method. In addition to the above, the present invention also includes a tungsten polygonal wire or a device in which holes are formed in a plate to mechanically join dissimilar metals or alloys.
[0021]
[Example 1]
A 65 μm diameter tungsten wire is cut to a length of 41 mm, and two holes having a diameter of 30 μm are shifted by 25 μm at a position 60 μm from one end. At this time, the laser used is a YAG short wavelength laser manufactured by Mitsubishi Heavy Industries, Ltd., which is a laser for fine processing having a wavelength of 266 nm and a spot diameter of 10 μm. This is shifted in the direction along the center line of the line as shown in FIG. The two holes are preferably connected in a bowl shape. 1 mm of a noble metal alloy wire having a diameter of 65 μm mainly made of palladium, silver, platinum, gold, or the like, which is known under the trade name of Parinay 7, is placed on the top of this hole, and laser light is irradiated in an argon atmosphere. PALINEY 7 (trade name) was developed by NEY of the United States and is a ternary alloy consisting of 35% by mass of Pd, 30% by mass of Ag, 10% by mass of Pt, 10% by mass of Au, 14% by mass of Cu and 1% by mass of Zn. . The energy of the laser irradiation at this time is such that tungsten does not melt (about 3400 ° C.) and the noble metal alloy wire melts (about 1800 ° C.). In this way, the noble metal alloy wire is melted from the end by the laser beam to become a spherical melt, which fills the above-mentioned holes and solidifies, and adheres to the tungsten hole wall. Thereafter, when the tip portion is polished and sharpened, a tungsten probe having a tip portion of a non-oxidizing noble metal alloy having a most advanced diameter of 25 μm is obtained. The noble metal alloy layer solidified with tungsten fixed with a relatively large contact area of complex shape, and was mechanically held so that it was fixed to the saddle wall as shown in FIG. In this state, a highly reliable bond was obtained with respect to bonding strength and conductivity.
[0022]
[Example 2]
A tungsten wire having a diameter of 80 μm is cut to a length of 41 mm, and 50 holes of 50 μm are opened from one end portion at intervals of 55 μm between cores using a micromachining drill. Since the holes are not connected, the laser beam is scanned to melt and remove the partition walls between the holes to form an oblong hole, and one end of the hole is also melted and removed to make it open. Next, using a fine processing forceps, it is expanded from the end of the oblong hole at an angle of about 30 degrees to form a mouth opening, and this is precious metal known under the trade name of the above-mentioned Parina 7 having a diameter of 60 μm and a length of 4 mm. Insert the alloy wire. When both ends of the expanded tungsten were closed with a strong force like a pliers, the tungsten was held in a shape held by the tungsten wall, and as a result, a strong bond satisfying the bonding strength and conductivity was obtained.
[0023]
Table 1 shows a performance comparison between the pencil type probe of Example 1 and Example 2 of the present invention and a conventional tungsten wire and noble metal alloy wire (Parina 7) probe. As a result, it was found that the pencil probes of Examples 1 and 2 of the present invention were superior to the conventional examples in terms of the wire diameter, elasticity, tensile strength, contact resistance, and the number of treatments until recleaning. .
[0024]
[Table 1]

[0025]
The present invention is not limited to a probe having a curved portion for a vertical probe card, and is applicable to a linear probe for a vertical probe card that has no curved portion and extends straight downward. It is. Further, the present invention is applicable to a probe for a cantilever type probe card, the tip of which is bent downward.
[0026]
【The invention's effect】
As is apparent from the above description, according to the present invention, a noble metal alloy having electrical conductivity and oxidation resistance is mechanically and electrically highly reliable at the tip of the tungsten probe. By doing so, a pencil type probe having a needle tip made of a noble metal alloy having the rigidity and elasticity of tungsten and good contact performance can be obtained. This pencil-type probe makes it possible to cope with the miniaturization of integrated circuits and the pitch size between electrodes becomes small, and contributes to the improvement of inspection processing capability of integrated circuits by reducing re-cleaning. To do. In addition, since the performance of the pencil-type probe can be maintained even when the diameter is reduced to 40 to 65 μm, not only the inspection of a semiconductor wafer but also the inspection of a liquid crystal driver having a smaller pitch dimension can be handled.
[Brief description of the drawings]
FIG. 1 shows a state in which two continuous holes are drilled in a tungsten wire.
FIG. 2 is a cross-sectional view taken along line AA of the tip of a pencil type probe in which a noble metal alloy is dissolved and embedded in a hole of a tungsten wire.
FIG. 3 shows a state in which the end portion of a tungsten wire is polished to sharpen a noble metal alloy.
FIG. 4 shows a state in which a hole row continuous to a tungsten wire is drilled.
FIG. 5 shows a state in which a noble metal alloy wire is inserted into a hole array expanded from the direction of an arrow.
FIG. 6 shows a state in which a noble metal alloy wire is sandwiched by closing an open portion of an expanded hole array of tungsten wires.
FIG. 7 shows a state in which a noble metal alloy portion at an end portion of a tungsten wire is polished and sharpened.
FIG. 8 is a cross-sectional view showing a configuration of a vertical probe card.
FIG. 9 is a diagram of a probe having a curved portion used for a probe card.
FIG. 10 is a diagram showing the external shape of a probe used in a vertical probe card.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100: Tungsten wire 200: Hole 201 opened in tungsten wire: Open end of hole array of tungsten wire 300: Noble metal alloy 1: Probe 1a: Curved portion 2: Guide portion 3: Substrate 4: Wafer mounting table 5: Wafer 51: IC chip 51a: Electrode

Claims (4)

  A hole having an inner diameter of 20 to 100 μm was continuously penetrated into the wire core by a microfabrication laser within a range of 2 to 3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 40 to 150 μm. Thereafter, a non-oxidizing noble metal or noble metal alloy having a melting temperature lower than that of tungsten is melt-embedded and fixed in the elongated hole row, and the end portion is polished to sharpen the noble metal or noble metal alloy portion. A method for manufacturing a pencil-type probe for a probe card.   A hole having an inner diameter of 20 to 100 μm was continuously penetrated into the wire core by a microfabrication laser within a range of 2 to 3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 40 to 150 μm. Then, after expanding from the open end of the hole row, inserting a non-oxidizing noble metal wire or noble metal alloy wire into the elongated widened hole row, sandwiching and gripping, then polishing the end A method for manufacturing a pencil-type probe for a probe card, comprising sharpening a noble metal or noble metal alloy part.   A plurality of adjacent holes having an inner diameter of 50 to 100 μm are pierced using a fine processing drill within a range of 2 to 3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 80 to 150 μm, and then the wire After the perforated wall in the axial direction is melted and removed with a micromachining laser to form a continuous elongated hole array, non-oxidizing noble metal or noble metal alloy having a melting temperature lower than that of tungsten is melt-embedded in the elongated hole array And then sharpening the noble metal or noble metal alloy portion by polishing the end portion, and a method for producing a pencil probe for a probe card.   A plurality of adjacent holes having an inner diameter of 50 to 100 μm are pierced using a fine processing drill within a range of 2 to 3 mm in the axial direction from the end of a tungsten wire or tungsten alloy wire having a diameter of 80 to 150 μm, and then the wire The wall of the perforations in the axial direction is melted and removed by a micromachining laser to provide a continuous elongated hole array, and then expanded from the open end of the hole array. Alternatively, after inserting a noble metal alloy, sandwiching and gripping, and then sharpening the noble metal or noble metal alloy portion by polishing the end portion, a method for producing a pencil-type probe for a probe card.

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