JP3888390B2 - Cleaning method and probing device for foreign matter adhering to probe tip - Google Patents

Description

  The present invention relates to an operation test (probing) technique for a semiconductor integrated circuit or a display device, and a foreign substance attached to the tip of a probe to be brought into contact with the operation test pad of the semiconductor integrated circuit or the display device, for example, metal or metal oxide, and electrical Removal member aimed at removing contaminants that obstruct contact, manufacturing method thereof, cleaning method for foreign matter adhering to the probe tip using the removal member, probe cleaned by the removal member, and removal member applied It is related with the probing apparatus.

  For example, a probe of a probe card that serves as an interface of an electrical signal exchanged between a probing device for measuring electrical characteristics of a semiconductor integrated circuit (hereinafter referred to as a semiconductor chip) formed on a semiconductor wafer and the semiconductor chip is as follows: The aluminum alloy bonding pad provided on the semiconductor chip was forced to come into contact with the semiconductor chip. For this reason, aluminum and aluminum oxide scraped from the pad material or contaminants remaining on the bonding pad surface adhered to the probe tip. Unless the adhered foreign matter is removed from the probe tip, the electrical resistance (contact resistance) between the probe and the bonding pad increases, making it difficult to accurately measure the electrical characteristics of the semiconductor chip. In addition, when the probe was used for a long time with adhered foreign substances accumulated, the electrical resistance increased with time. As a countermeasure, every time a predetermined number of probings are performed, the probe tip is cleaned to remove the adhering foreign matter.

  For example, in Japanese Patent Application Laid-Open No. 7-244074, a fine abrasive powder for polishing is mixed with a base material having elasticity and formed into a sheet shape to form a polishing sheet, that is, a cleaning sheet. This cleaning sheet is used as a semiconductor wafer and a probe card. Mounted on the wafer moving table of the probing device that realizes the contact operation instead of the semiconductor wafer, moves the wafer moving table up and down and presses the probe tip against the surface of this cleaning sheet, and disperses the probe tip surface and the cleaning sheet A method is disclosed in which foreign matter adhering to the probe tip is removed by generating contact friction with the polished abrasive grains.

  Japanese Patent Laid-Open No. 11-97496, which has already been disclosed as an invention by the inventors of the present invention, has a resin material surface coated with a metal thin film having high tensile strength, and the metal thin film surface is coated with a ceramic layer or abrasive grains. A technique for removing foreign substances adhering to the tip of a probe using a cleaning sheet provided with a polishing layer to which is adhered is disclosed.

  Further, for example, in Japanese Patent Application Laid-Open No. 11-345846 or Japanese Patent Application Laid-Open No. 10-300777, a thin film for cleaning is formed on an elastic sheet to form a cleaning sheet. Techniques for removal are disclosed.

Japanese Patent Laid-Open No. 7-244074 JP-A-11-97496 Japanese Patent Laid-Open No. 11-345846 Japanese Patent Laid-Open No. 10-300777

  A conventional cleaning sheet for removing foreign substances adhering to the tip of a probe is formed by mixing a fine abrasive powder with an elastic base material as described above. Since the cleaning sheet is deformed when pressed against the surface of the cleaning sheet, the probe 1 is pushed into the base material 102 as shown in FIG. There is a problem that the tip of the probe is cut and thinned during repeated cleaning, and the probe 1 itself is bent or bent due to insufficient strength.

  Further, according to the research by the present inventors, the probe tip shape is a substantially spherical shape having a specific diameter R that is deeply related to the thickness of the pad electrode material that is the contact partner or the contact tip between the probe tip and the semiconductor electrode pad. Recently, it has become clear that a shape having a flat portion in a part of a substantially spherical shape (hereinafter collectively referred to as a substantially spherical shape) is suitable. When such a probe is used, when a conventional cleaning method using a cleaning sheet is applied, the probe tip having a substantially spherical shape is scraped and deformed by the cleaning operation, resulting in deterioration of electrical contact of the probe. There was a problem.

  In order to solve the above problems, the present inventors have invented a cleaning sheet, that is, a removing member, that can clean the adhered foreign matter while deforming along the shape of the probe tip. Although disclosed in Japanese Patent No. -97496, there is room for further improvement regarding the problem of dust generation due to peeling or dropping of the abrasive material of the ceramic coating polishing layer or abrasive polishing layer formed on the surface of the cleaning sheet.

  Japanese Patent Laid-Open No. 10-300777 or Japanese Patent Laid-Open No. 1-345846 was devised for the same purpose as the above prior art, that is, for the purpose of preventing the probe tip from being scraped and deformed during cleaning. Although a technique related to a cleaning sheet has been disclosed, some problems described below still remain in order to exhibit a polishing function along the shape of the probe tip.

  In fact, even if the probe tip is cleaned using a cleaning sheet manufactured and marketed based on the contents of the above-mentioned publication, the probe tip portion is not flexible because the cleaning sheet is not flexible enough, that is, the cleaning deflection rigidity is high. As a result of the contact pressure damaging the surface of the cleaning sheet due to plastic deformation and deepening the abrasive grain layer, there is a problem that the life of the cleaning sheet is shortened. In addition, some problems remain in practical use, such as inability to clean all foreign matter adhesion regions on the probe tip surface.

  Furthermore, in order to efficiently polish the tip of the probe and prolong the polishing life of the cleaning sheet, the probe tip needs to slide smoothly while in contact with the surface of the cleaning sheet, and the probe tip shape can be maintained well. Further improvement to realize an ideal cleaning sheet was indispensable.

  Also, due to the recent trend toward narrower pitch and higher pin count of semiconductor electrode pads, a probe called a membrane probe, which does not use a wire material like conventional probe cards, and has electrode projections arranged in a plane, is in the near future. Although it is expected to be frequently used, there has been a problem that the cleaning sheet of the piercing method cannot be used for cleaning the protruding portion of the membrane probe. Similar to this membrane probe, there is a similar problem with vertical probe type probe cards in which the needle holder density is increased by vertically arranging the wires, that is, the cleaning sheet of the piercing method cannot be used. It was an obstacle to.

  The present invention has been devised to solve the above-mentioned problems, and prevents the tip of the probe from being cut and thinned, and removes foreign matter adhering to the tip of the probe while maintaining the probe tip shape. A probe tip adhering foreign matter removing member capable of extending the life of the probe, a method of manufacturing the removing member, an efficient cleaning method of the probe using the removing member, a probe cleaned by the removing member, and It is an object of the present invention to provide a probing apparatus to which the removing member is applied.

The probe tip foreign matter cleaning method according to the present invention includes a base plate, a first elastic member formed on the base plate, a second elastic member formed on the first elastic member, and a second member. of an elastic hard particles are formed on the member and the binder material abrasive layer formed of, with a Young's modulus of the first elastic member and 5 kgf / mm ² or more 400 kgf / mm ² or less, the second elastic member The film thickness is 0.1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, the removing member of the probe tip attached foreign matter particle size and 0.1μm or 9μm or less placed on a wafer stage, a probe tip exhibits a shape with a flat portion in a part of the substantially spherical or substantially spherical, top predicate Removal part It was decided to remove the tip adhesion foreign matters probe to by sliding operation draws a locus of circular or rectangular loop shape on top.

The probing device according to the present invention includes a base plate, a first elastic member formed on the base plate, a second elastic member formed on the first elastic member, and a second elastic member. comprises a formed composed of hard particles and a binder material polishing layer, and the Young's modulus of the first elastic member and 5 kgf / mm ² or more 400 kgf / mm ² or less, the thickness of the second elastic member 0. 1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, and the particle size of the hard particles is 0.00 . and removing member of the probe tip attached foreign matter and 1μm or more 9μm or less, and the probe exhibits a shape tip with a flat portion in a part of the substantially spherical or substantially spherical, the probe on the above-described removal member which is Installation Circular or square The horizontal and vertical directions movable wafer stage provided as sliding operable locus of closed loop shape, with a.

In the probe tip foreign matter cleaning method according to the present invention, a base plate, a first elastic member formed on the base plate, a second elastic member formed on the first elastic member, and a second of an elastic hard particles are formed on the member and the binder material abrasive layer formed of, with a Young's modulus of the first elastic member and 5 kgf / mm ² or more 400 kgf / mm ² or less, the second elastic member The film thickness is 0.1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, the removing member of the probe tip attached foreign matter particle size and 0.1μm or 9μm or less placed on a wafer stage, a probe tip exhibits a shape with a flat portion in a part of the substantially spherical or substantially spherical, top predicate Removal Since the order by sliding operation draws a locus of circular or rectangular loop shape on wood it was decided to remove the tip adhesion foreign substances probe, while keeping the probe tip shape, the adhesion foreign matter of the probe tip efficiently Can be cleaned.

In the probing device according to the present invention, the base plate, the first elastic member formed on the base plate, the second elastic member formed on the first elastic member, and the second elastic member are provided. comprises a formed composed of hard particles and a binder material polishing layer, and the Young's modulus of the first elastic member and 5 kgf / mm ² or more 400 kgf / mm ² or less, the thickness of the second elastic member 0. 1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, and the particle size of the hard particles is 0.00 . and removing member of the probe tip attached foreign matter and 1μm or more 9μm or less, and the probe exhibits a shape tip with a flat portion in a part of the substantially spherical or substantially spherical, the probe on the above-described removal member which is Installation Circular or square Jo of the horizontal and vertical directions movable wafer stage provided to track the sliding operable in a closed loop shape, so with a while maintaining the tip shape of the probe forming part of a probing device, The foreign matter adhering to the probe tip can be cleaned efficiently and easily.

  The present invention provides a base plate and a removal member on the base plate for removing foreign matter adhering to the spherical tip of a test probe that contacts the bonding pad of the semiconductor chip to test the operation of the semiconductor chip. Material properties that can be flexibly deformed by contact with the probe, specifically, a first elastic member having a predetermined Young's modulus, and contact stress generated by contact with the probe formed on the first elastic member. A smooth sliding motion of the probe is realized by mixing the second elastic member with tensile strength and film thickness that can be accommodated, and the hard particles and binder material formed on the second elastic member in a predetermined volume ratio. In addition, the polishing layer with high efficiency of adhering foreign matter, and the above four layers as the main part, makes the probe smoothly slide on the removal member and efficiently removes the adhering foreign matter at the probe tip. It is that to be able to removed by. Further, the present invention provides a cleaning method for efficiently removing foreign matter attached to the probe tip using this removing member, and a probe from which the foreign matter attached to the tip does not affect the contact characteristics by this cleaning method. In addition, the present invention provides a probing apparatus that can carry out such a cleaning method by applying the removing member.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating the function of a probe tip foreign matter removing member according to Embodiment 1 of the present invention. In the figure, 1 is a probe, 1c is a probe tip spherical surface, 2 is a wafer table, 3 is a base plate, 4 is an elastically deformable member, 4a is a first elastic member, 4b is a second elastic member, and 5 is a polishing layer. 5a shows hard particles, 5b shows a binder material, and 10 shows a probe card. In FIG. 1, a portion where the probe tip 1c is in contact with the surface of the elastically deformable member 4 is shown enlarged.

  A probe card 10 for testing a semiconductor chip after energization by bringing a probe into contact with a bonding pad of the semiconductor chip is generally configured by arranging metal wires, for example, tungsten needles, on a substrate in accordance with a pad arrangement. In the member for removing foreign matter adhering to the probe tip in the present embodiment, a member 4 that can be elastically deformed flexibly as a cleaning sheet base material is used so that the polishing layer 5 having a polishing action extends along the probe tip spherical surface 1c. The elastically deformable member 4 is a membrane that can resist the tensile stress generated by the contact between the first elastic member 4a made of a material having a high ability to be flexibly deformed and the probe tip 1c. It is composed of two layers of a second elastic member 4b having a small thickness and high tensile strength.

  Based on FIG. 2, the probe tip foreign matter removing member, that is, the cleaning sheet in this embodiment will be described.

  The surface of the cleaning sheet is deformed along a substantially spherical shape (for example, a curvature radius R = 5 to 30 μm) 1c of the probe tip 1c. A more detailed configuration of the cleaning sheet of the present embodiment that can be brought into close contact with the probe tip surface, which is a region where aluminum adhesion occurs, will be described below. The probe tip shape is an effective cleaning sheet for the substantially spherical shape as described above and for the case where a flat portion is provided on a part of the substantially spherical surface of the probe tip.

(1) Configuration of cleaning sheet (a) First elastic member 4a
As the mechanical properties of the first elastic member 4a, range Young's modulus of 5~400kgf / mm ² of the material of the first elastic member 4a is preferably, and more preferably in the range yet 5~100kgf / mm ² . The reason why such a Young's modulus range is suitable will be described below.

When the Young's modulus of the first elastic member 4a is less than 5 kgf / mm ² , even if the diameter R of the spherical surface of the probe tip 1c is about 5 to 10 μm, an area of about 80% of the probe tip spherical surface, that is, the projection surface. The cleaning sheet can be brought into close contact with an area having a diameter ratio of 80%. Considering the present situation that the diameter R of the spherical surface of the probe tip 1c is hardly 5 μm or less, the Young's modulus of the first elastic member 4a is 5 kgf / mm ² or more, which is practically sufficient. On the other hand, when the Young's modulus of the first elastic member 4a is less than 5 kgf / mm ^{2, the} amount of wrapping becomes too large even if the probe tip is actually brought into contact with the cleaning sheet, and smooth sliding characteristics cannot be obtained. Arise.

Further, although the upper limit of the Young's modulus depends on the probe tip diameter and the contact load, the Young's modulus of the first elastic member 4a, the shape of the probe tip, and the probe contact force have a certain correlation and can be assumed. When the probe 1 having the largest tip sphere diameter R30 to 50 μm is brought into contact with a general contact force of 5 to 10 g, the aluminum region that can adhere to the probe tip 1 c is only a circular region having a diameter of 10 to 20 μm at most. In other words, the flexibility that can clean the circular region of this level is not limited to about 400 kgf / mm ² or less.

Furthermore, it is ideal that the probe tip 1c is in contact with the cleaning sheet so as to completely cover the aluminum adhesion region. To realize such a state, the Young's modulus of the first elastic member 4a is 100 kgf / It is more preferable that it is ² mm or less.

Therefore, in the probe tip foreign matter removing member of the present embodiment, a silicon resin (silicon rubber) material having a Young's modulus of about 100 kgf / mm ² or less is used as the first elastic member 4a. If it is an elastic material that satisfies the above conditions, that is, 5 to 400 kgf / mm ² , the same effect can be obtained with other resin materials such as urethane resin, fluororesin, polypropylene resin, and materials having rubber properties such as plates and sheets / films. Needless to say.

Recently, as an adverse effect of increasing the density of semiconductor chips, in order to increase the number of signal input / output pads (I / O pads), the number of power supply pads for supplying drive current to the semiconductor chips has been reduced to achieve a power saving design. On the other hand, the value of current flowing through one power supply pad tends to increase. That is, the value of the current flowing through the test probe that is in contact with the power supply or the ground pad is also increasing, and welding of aluminum due to Joule heat generation due to the contact resistance of the contact portion is becoming a problem. This welded aluminum grows so that the welded area is expanded at the probe tip 1c. Further, since the welded aluminum attached to the probe tip 1c is strong, a small dent may be formed in the probe tip 1c due to the contact pressure between the probe 1 and the electrode pad of the semiconductor chip, so that the welded aluminum is removed. More and more, a cleaning sheet that wraps the probe tip 1c and can be flexibly deformed is required. It is essential that the Young elastic modulus of the first elastic member 4a is 400 kgf / mm ² or less as a material having this enveloping ability, that is, a flexible deformation ability. In the present embodiment, as an example, a two-component mixed curable silicone rubber whose hardness can be slightly changed depending on the blending ratio is employed. However, the material having such properties is not limited to the two-component mixed curable silicone rubber, and the first elastic material can be used as long as it is a general silicone rubber within the above Young's modulus range. It can be used as the member 4a.

The silicon rubber used in the present embodiment is a material having a substantial Young's modulus of 10 to 30 kgf / mm ² and very flexible, and this constitutes the first elastic member 4a of the cleaning sheet.

(B) Second elastic member 4b
In the member for removing foreign matter adhering to the probe tip of the present embodiment, the second elastic member 4b is formed on the surface of the first elastic member 4a, and the probe tip 1c is elastically deformed by the contact pressure with the probe. I try not to pierce it.

For example, when a probe having a probe tip diameter of φ30 μm and a tip sphere diameter R of 20 μm contacts the cleaning sheet with a contact force of 7 g, the tensile stress acting on the cleaning sheet surface is about 5 kgf / mm ² . Therefore, with the general tensile strength of silicon rubber that maintains flexibility, the probe tip 1c breaks the surface of the silicon rubber and pierces the silicon rubber. If the probe tip 1c pierces the cleaning sheet, the probe 1 is deformed and the probe card becomes unusable. Therefore, it must be avoided. Therefore, a film having a high tensile strength is coated on the first elastic member 4a as the second elastic member 4b so as to withstand the contact stress of the probe 1.

Regarding the tensile stress of the second elastic member 4b, a tensile stress of less than 0.1 kgf / mm ² is applied even when the probe has a sphere diameter R of about 30 to 50 μm and the contact force is about 5 to 7 g. It has been found that the second elastic member 4b (for example, PET film) having the second elastic member 4b itself is torn. Therefore, the second elastic member 4b needs to have a tensile stress of 0.1 kgf / mm ² or more, that is, a tensile strength, but considering the variation of the tensile stress of the material itself, 0.4 kgf / mm ² or more is required. More preferred.

  Further, since the second elastic member 4b is also required to have flexibility to follow the deformation of the first elastic member 4a, a material that satisfies the above two conditions can be formed thin and has high tensile strength and elongation. It is limited to a certain resin material.

  In this embodiment, a polyimide film is selected as a material that satisfies these two conditions. In addition to polyimide resins, various engineering plastics such as polyamide resins, POM (polyoxymethylene) or PES (polyethersulfone) resins can be used as materials that satisfy the requirements of the present embodiment. Furthermore, as long as the resin material satisfies the above material characteristics, other resin materials such as a laminate film of polyethylene and polyamide resin and a fiber reinforced composite material of polyvinyl chloride can be used without any problem.

In order to be able to follow the deformation of the first elastic member 4a while utilizing the property of high tensile strength, it is desirable to make the second elastic member 4b as thin as possible. When the probe 1 is in contact with 5 to 10 g, which is a general contact force range, the deformation amount (sink amount) of the first elastic member 4a when the Young's modulus is several tens kgf / mm ² is 10 μm or more. It becomes. As a result of experiments using a polyimide resin material on the thickness of the second elastic member 4b that can follow the amount of deformation, the deformation capability (deflection capability) is insufficient unless the thickness of the second elastic member 4b is 20 μm or less. It was found that the probe tip 1c was not wrapped. Actually, when the thickness of the second elastic member 4b exceeds 20 μm, the deformation due to the contact of the probe 1 is governed by the mechanical strength of the second elastic member 4b, and the first elastic member 4a provided with great effort is provided. It turned out that the effect of the flexibility which can follow a deformation | transformation becomes small.

  In addition, if the above-described bending ability of the second elastic member 4b is insufficient, the deformation of the cleaning sheet due to contact affects the contact state of adjacent probes with respect to the probe tips 1c arranged at a narrow pitch of about 100 μm, for example. When the contact is made, the probe between the pins falls into a state where the contact surface with the cleaning sheet becomes small. That is, the object of the present invention is achieved by combining a film type cleaning sheet having a base of several tens of μm or more (bending rigidity or bending rigidity is high) and a flexible material on the lower surface of the cleaning sheet. It was impossible at all. Therefore, the thickness of the second elastic member 4b employed in the present embodiment is set to 20 μm or less.

  Also, as a result of the experiment, it is clear that when the film thickness of the second elastic member 4b is 5 μm or less, the contact between the probe tip 1 and the cleaning sheet is further improved and the polishing effect on the probe adhering foreign matter is further improved. It became.

  On the other hand, regarding the lower limit of the film thickness of the second elastic member 4b, it is necessary to set it to 0.1 μm or more in order to stably control the film thickness of the second elastic member 4b due to manufacturing problems described later. is there. Further, it has been experimentally found that the second elastic member 4b having a film thickness of less than 0.1 μm is easily broken by contact with the probe 1. This is presumably because the film thickness uniformity is not constant over the entire cleaning sheet. However, the numerical value of 0.1 μm is a lower limit when the second elastic member 4b is stably formed. In view of various process variation factors during manufacturing, in order to form more stably, 0.5 μm The above is more preferable.

  From the above consideration, it was found that the film thickness of the second elastic member 4b is preferably in the range of 0.1 μm to 20 μm, more preferably 0.5 μm to 5 μm.

(C) Polishing layer 5
The polishing layer 5 is formed on the second elastic member 4b. The polishing layer 5 needs to have both the function of removing the adhered foreign matter on the probe tip 1c and the two functions of sliding the probe tip surface. Therefore, the polishing layer 5 is composed of a mixed layer of hard particles 5a that can remove foreign matter adhering to the probe tip 1c, and a binder material 5b that can fix the hard particles 5a and maintain the cleaning sheet surface in a relatively smooth state. did.

  The hard particles 5a used as the abrasive grains are the surface of the abrasive layer 5 as in ordinary abrasive materials (what is called a wrapping film or abrasive tape shown as an abrasive layer in JP-A-10-300777). If it is exposed largely on the top, there will be a problem of damaging the probe tip. Here, the scratch means a scratch having a depth of 1 μm or more.

  Accordingly, the surface of the binder material 5b to which the hard particles 5a are fixed is broken or deformed by the contact pressure of the probe 1, so that the surface of the hard particles 5a and the surface of the probe tip 1c can be brought into contact with each other. Was set to be a mixed layer of the hard particles 5a and the binder material 5b. Here, the mixed layer is called a mixed layer, unlike the conventional polishing material in which hard particles or hard materials are in direct contact with the probe 1, and the polishing layer 5 realizes a smooth sliding operation with the probe 1 simultaneously with the polishing action. This is because the binder material 5b containing the hard particles 5a must also bear a part of the contact surface pressure with the probe 1.

  The important point here is that the second elastic member 4b receiving the tensile strength and the polishing layer 5 must be clearly separated. That is, if the hard particles 5a serving as the abrasive grains are directly fixed to the second elastic member 4b receiving the tensile strength, the contact pressure of the probe 1 via the hard particles 5a during the probe contact causes the second elasticity. Directly transmitted to the member 4b, the hard particles 5a damage the second elastic member 4b. As a result, the second elastic member 4b responsible for the tensile strength is broken and the probe 1 is stuck into the cleaning sheet. . In order to deal with such problems, it is important that the polishing layer 5 is composed of a mixed layer of the hard particles 5a and the binder material 5b, and the force received by the hard particles 5a is dispersed by the binder material 5b. The hard particles 5a that can be used from the condition that the abrasive grains can be uniformly dispersed with respect to the film thickness of the second elastic member 4b can be used if the particle size is 9 μm or less, and a sufficient effect can be obtained at about 5 μm. I understood. The particle diameter of the hard particles of 5 μm corresponds to about # 3000 as a general cleaning sheet material. The smaller the particle size of the hard particles 5a, the more effectively it functions. However, in view of the effect of the polishing action, the lower limit is preferably 0.1 μm or more.

  In the member for removing foreign matter adhering to the probe tip in the first embodiment of the present invention, alumina abrasive grains (particle size: # 8000, average particle size 2 μm) are used as the hard particles 5a, and a urethane resin-based resin material is used as the binder material 5b. It was used. In this case, the mixing ratio of both was alumina abrasive grains: urethane resin = 1: 4 to 1: 8 volume ratio. From the experimental results, it was found that if the amount of urethane resin is too small, the probe 1 breaks the second elastic member 4b and pierces the cleaning sheet or the alumina abrasive grains fall off, causing dust generation. Moreover, when the volume ratio of the urethane resin was too high, it discovered that the grinding | polishing efficiency with respect to the aluminum deposit | attachment of the probe tip 1c fell.

  The urethane resin used in the present embodiment has an appropriate hardness, and the sliding motion of the probe tip 1c is good, which is suitable as the binder material 5b for forming the mixed layer (polishing layer 5) with the hard particles 5a. Moreover, the urethane resin was able to ensure moderate wettability and adhesive strength even with respect to the polyimide resin employed as the second elastic member 4b as the base. However, since engineering plastics having high mechanical strength, such as polyimide resin, are chemically quite stable, the surface of the above polyimide resin is made of an organic solvent such as tetrahydrofuran in order to ensure bonding strength with urethane resin. It was found that it was necessary to swell and activate in advance.

  Further, as a result of the experiment, the cleaning efficiency and the probe tip 1c were adjusted such that the volume ratio of the hard abrasive grains was 5 to 70% with respect to the entire polishing layer 5 as the blending ratio of various hard abrasive grains other than alumina abrasive grains and urethane resin. It was found that both of the sliding characteristics of the polishing layer 5 can be secured satisfactorily, and the polishing layer 5 capable of achieving both the polishing efficiency of the adhering foreign matter and the sliding characteristics of the probe tip 1c within such a range can be realized. Further, it has been found that this effect becomes more effective when the volume ratio of the hard abrasive grains is in the range of 10 to 20%.

  Japanese Patent Laid-Open No. 10-300777 cited as the prior art of the present embodiment also describes the blending ratio of the binder material 5b and the hard particles 5a, and the volume ratio of the hard particles 5a is about 80% of the whole (abrasive abrasive grains) : Polyester resin = 4: 1) is said to be good, but the general blending ratio disclosed in the prior art, that is, the volume ratio of about 80%, the polishing efficiency with respect to adhered foreign matters is certainly good. Experiments in the present embodiment have revealed that it is difficult to realize a smooth sliding operation between the polishing layer 5 and the probe tip 1c, which is one of the important objects of the invention. Incidentally, the reliable polishing efficiency means that the probe 1 and the cleaning sheet are subjected to a relative displacement amount of 50 to 100 μm as a forced contact amount (overdrive amount), and when the contact is repeated about 10 to 100 times, It refers to the polishing efficiency that can remove the adhered aluminum.

  As described above, alumina abrasive grains and urethane resin are taken as examples of the constituent elements of the polishing layer 5, but the hard particles 5a include ceramic particles such as diamond, silicon (Si), silicon carbide (SiC), etc. in addition to alumina. In addition, any other material may be used as long as it has a hardness capable of removing foreign substances adhering to the probe tip 1c.

  In addition to urethane resin adhesives, binders such as epoxy and acrylic adhesives are also effective as the binder material 5b. Furthermore, the second elastic member 4b (in this embodiment, a polyimide material) is also effective. Any material may be used as long as it has adhesiveness and adhesiveness and has a material strength that does not easily peel off or drop off with respect to the contact force of the probe 1.

(D) Base plate 3
In the case of the member for removing foreign matter adhering to the probe tip in the present embodiment, a silicon wafer is used as the base plate 3, but a probing apparatus having a wafer table 2 (a probing test by loading and unloading a wafer in which a semiconductor device is built) If the cleaning device recognizes the cleaning sheet and can be loaded / unloaded on the wafer table 2, it can be used by orientation-flatting or notching the resin plate or metal plate.

(2) Cleaning Sheet Manufacturing Method Next, the main points of the probe tip foreign matter removing member having the above-described configuration, that is, the cleaning sheet manufacturing method will be described. In order to provide the second elastic member 4b as a thin film having a thickness of 20 μm or less on the surface of the first elastic member 4a, the following method is required for the manufacturing method.

  First, it is necessary to ensure the flatness of the first elastic member 4a. As a cleaning sheet with which the probe 1 comes into contact, in order to bring a large number of probe tips 1c into contact with the surface of the cleaning sheet at the same time, a flatness of about 10 μm, which is half of the height variation ± 10 μm of a general probe tip 1c, is obtained. Of course, the flatness of 10 μm or less is also required from the viewpoint of forming a thin film made of a uniform second elastic member 4 b of 20 μm or less on the surface of the first elastic member 4 a by spin coating. It is necessary to secure.

  Therefore, as a method of forming the first elastic member 4a, the base plate 3 shown in FIG. 1 or FIG. 2 is used as a substrate material, and a two-component mixed curable silicon material is poured on the surface of the substrate material, and the flatness is measured. And the flatness of the surface of the first elastic member 4a could be reduced to 10 μm or less. The substrate material used was an 8-inch silicon wafer, and the flatness of the substrate material itself was 5 μm or less.

  In general, the height variation of the probe 1 of the probe card in which several to thousands of probes are arranged is about 20 μm in Max-Min, the flatness of the first elastic member 4a itself is 10 μm, and the wafer table 2 of the probing apparatus 2 Since the height positioning variation is 10 μm, in order for the probe tip 1c to make good contact with the cleaning sheet in the entire probe card in which a plurality of probes 1 are erected, there is a margin in the sinking stroke of the first elastic member 4a. As a result, the film thickness of the first elastic member 4a needs to be 50 μm or more. From this knowledge, the film thickness of the first elastic member 4a is set to 100 μm in this embodiment. However, in the experiment carried out with respect to the present invention, the height variation of the probe tip 1c is somewhat corrected by the probe 1 coming into contact with the cleaning sheet. Therefore, the first elastic member 4a exhibits the minimum function even when the film thickness is 30 μm. It turns out that you can.

  In this embodiment, the first elastic member 4a is press-molded. However, if there is a silicon rubber sheet having a uniform film thickness, the first elastic member is bonded to the upper portion of the base plate 3 by bonding the silicon rubber sheet. There is no problem even if it is used as 4a.

  Next, the second elastic member 4b needs to be thinned and formed on the surface of the first elastic member 4a. In order to form a thin film having a thickness of 20 μm or less uniformly and stably, it is most appropriate to use the spin coating method, but in order to use the spin coating method, a material that is the basis of the second elastic member 4b. The initial form of must be liquid. As a material that exhibits a function of forming a film having a high tensile strength after being thinly coated in a liquid state, the polyimide used in the present embodiment was an optimal material. However, the polyimide needs to be baked (baked), but since the silicon rubber is applied to the first elastic member 4a, it must be baked at a baking temperature lower than the heat resistant temperature of the silicon rubber. There are limitations.

  Therefore, in the embodiment of the present invention, the second elastic member 4b is configured by selecting a polyimide material having a baking temperature of 300 ° C. or lower. Also, when applying polyimide raw material on silicon rubber, the surface of silicon resin is cleaned and activated in advance using an organic solvent such as NMP (N-2 methylpyrrolidone) to improve wettability. ing. However, a film having a film thickness of 20 μm or less, such as polyimide or polyamide, may be prepared and formed on the surface of the first elastic member 4a by being laminated by a vacuum press or a roller. Needless to say, mass production becomes easier.

  The important point here is that a cleaning sheet that has conventionally existed as an alternative to the combination of the second elastic member 4b and the polishing layer 5 described in the present invention, that is, a cleaning sheet having a base material thickness of several tens of micrometers or more. Even if the base material is applied as it is, the bending rigidity or bending rigidity of the base material is too large, so that it cannot be deformed along the probe tip shape. Only about one third of the contact area can be obtained.

  On the other hand, by applying the second elastic member 4b having a film thickness of 20 μm or less shown in the present embodiment, about 80% of the probe tip having a general probe tip diameter (φ10 to 60 μm) is covered. A cleaning sheet that can be obtained can be obtained.

  As described above, the flexible first elastic member 4a is formed thick on the base plate 3 made of the substrate material, and the second elastic member 4b is formed on the first elastic member 4a in a thickness of 0.1 to 20 μm. By forming the polishing layer 5 formed of a resin thin film and further comprising the hard particles 5a and the binder material 5b at the above-described predetermined mixing ratio on the second elastic member 4b, it is possible to efficiently follow the probe tip shape. A cleaning sheet capable of removing the adhering foreign matter on the probe tip 1c could be manufactured.

  The cleaning sheet of the present invention is designed so that the total thickness including the base plate 3, the elastically deforming member 4, and the polishing layer 5 is 1.5 mm or less. By limiting the thickness of this cleaning sheet and reducing its weight, the loader load on the probing device can be reduced, and the conventional wafer transfer jig can be used as it is, and it is loaded and unloaded as if it were a semiconductor wafer. It becomes possible. However, even if the total thickness of the cleaning sheet of the present invention is 1.5 mm or more, the original effect of the cleaning sheet is not impaired.

Embodiment 2. FIG.
Based on FIGS. 3 and 4, a method for cleaning the probe to which the probe tip foreign matter removing member according to the second embodiment of the present invention is applied will be described. In the figure, 1b is a probe horizontal portion, 6a is a scraped foreign matter, and 6b is a scrub mark.

As described in the first embodiment, the current flowing through the power supply or the ground tends to increase with the increase in the capacity of the semiconductor chip, and the heat generated by the contact stress of the probe 1 and the energizing current has a synergistic effect. Aluminum welding to the probe tip 1c is increasing. For example, in a DRAM or the like, pulsed current supply is performed at regular intervals accompanying a refresh operation for holding memory contents, but the current flowing through the power supply pin of the semiconductor chip reaches 300 mA instantaneously (inrush current). In some cases, if the diameter R of the sphere at the tip of the probe is 30 μm, the current density of this portion has reached a level exceeding 400 A / mm ² , and the probe tip 1 c is instantaneous but is several hundred degrees due to instantaneous heat generation. May rise.

  For this reason, for example, even in a probe made of a high melting point tungsten material, as shown in FIG. 2 of the first embodiment, the phenomenon that the aluminum which is the attached foreign matter 1a of the probe tip 1c bites into and adheres to the probe material side. occured. The adhering aluminum that has digged into the probe side is difficult to remove with the conventional cleaning sheet, and the adhering aluminum is used as a nucleus to further expand the adhesion area of the aluminum, thereby deteriorating the electrical contact performance of the probe. It became clear by the study of.

  Based on FIG. 3, a conventional cleaning method and a cleaning method using a probing apparatus used for a wafer test will be described. For the sake of convenience, the cleaning sheet in the figure is not the conventional one but the one in the first embodiment.

  In the probe card called the cantilever method, the probe 1 arranged on the substrate of the probe card 10 is connected to the probe card 10 and fixed to the substrate of the probe card 10 by being connected to the probe card 10 and having a probe tip spherical surface 1c. The probe horizontal portion 1b is formed. In the conventional cleaning sheet, after the cleaning sheet mounted on the wafer table 2 (also referred to as a wafer chuck top) of the probing apparatus and the probe tip 1c of the probe card 10 are slightly in contact, an operation called overdrive (OD) is performed. That is, the probe tip 1c is cleaned by piercing the probe tip 1c into a conventional cleaning sheet by the Z-direction (vertical direction) movement of the wafer table 2. By using this piercing operation for the cleaning sheet shown in the first embodiment, the probe tip 1c can be cleaned by sliding on the surface of the cleaning sheet.

  That is, in the cleaning sheet of the first embodiment, the elastically deformable member 4 having the two-layer structure is provided on the base of the polishing layer 5 that exhibits the cleaning function, so that the sliding operation is performed in accordance with the Z-direction operation of the wafer table 2. It became possible to wake up. As shown in FIG. 3, after the probe tip spherical surface comes into contact with the cleaning sheet surface, the probe 1 is lifted by raising (overdrive) the wafer table 2 in the Z direction. As 1b rotates upward, a probe sliding operation (scrub amount) occurs on the cleaning sheet.

  In the case of a conventional cleaning sheet, the probe tip 1c bites into the cleaning sheet almost immediately after overdrive. However, the cleaning sheet of the first embodiment in which the surface of the cleaning sheet is not torn is a force caused by a reaction from the probe 1 ( Since the horizontal portion of the probe is bent upward and rotated, the probe tip on the cleaning moves, resulting in a constant scrubbing action, that is, a sliding action.

  When a general probe card is used, a slip amount of about 20 to 30 μm is generated with an overdrive amount of 70 μm (the slip amount varies due to the influence of probe height variation). By this sliding, the foreign matter adhered to the probe tip 1c comes into contact with the ceramic member of the cleaning sheet to realize a frictional operation, and the foreign matter adhered to the probe tip 1c is removed. However, in the probe sliding operation that occurs in the Z direction of the wafer table 2 that occurs in the conventional method, that is, in the vertical direction, the amount of sliding per one time is about 30 μm, so it is necessary to completely remove the adhered foreign matter. It was necessary to repeat the contact operation many times.

  On the other hand, if the cleaning sheet of the present invention is not torn against the contact stress generated at the probe tip 1c and the probe tip 1c slides while contacting the surface of the cleaning sheet, an efficient cleaning method can be obtained. can get. That is, after giving a certain amount of overdrive in the Z direction, the wafer table 2 is moved in the XY direction, that is, in the horizontal direction, and a long-distance slip amount is obtained at once. This cleaning method corresponds to repeating the sliding amount of 30 μm by the Z-direction overdrive in the conventional cleaning method 1000 times only by setting the sliding amount to 30 mm.

  In addition, since such a cleaning method can cause a sliding motion while keeping the most effective contact pressure constant, it provides an effect of obtaining a much higher polishing efficiency for adhering foreign matter than a simple calculation based on a proportional number of times. .

  Such a cleaning method is a cleaning method that could not be realized with a conventional piercing type cleaning sheet or a cleaning sheet in which a portion corresponding to the second elastic member 4b is formed of a thick base film.

Embodiment 3 FIG.
When a long-distance slip amount is generated using the cleaning sheet of Embodiment 1, the constituent material of the polishing layer 5 on the surface of the cleaning sheet is scraped to the probe tip 1c by the probe tip 1c. It may adhere to the probe tip 1c. In this case, if the locus that causes the sliding movement of the probe tip 1c and the cleaning sheet is set in a closed loop shape in advance, for example, in the case of a square closed loop movement as shown in FIG. Since it leaves | separates from 1, the above-mentioned trouble can be solved. If a sliding motion of one rotation or more is caused in the closed loop shape, the probability that the scraped constituent material can remain on the cleaning sheet side is increased.

  In addition to the closed loop operation, the probability that the scraped constituent material can remain on the cleaning sheet side is increased by the zigzag or S-shaped continuous operation.

  The closed loop shape is not particularly limited to a circle or a quadrangle. In addition, the same effect can be expected by simply giving a reciprocating motion, but it can be said that this also draws a closed-loop trajectory strictly considering the rattling of the probing device.

  FIG. 5 shows a schematic diagram of an SEM (Scanning Electron Microscope) observation image in a state where aluminum is adhered to the probe tip 1c by repeating the probing test. FIGS. 6 and 7 schematically show SEM observation images of the results of comparing the cleaning effect of the above-mentioned probe to which the aluminum is adhered with the conventional and cleaning sheets according to the present invention. In the figure, 1d indicates a polishing flaw.

  It was confirmed that the probe tip 1c cleaned with the conventional cleaning sheet shown in FIG. 6 was formed with scratches caused by the contact with the cleaning sheet in the sliding direction. From FIG. 6, the adhered aluminum is almost removed, but it can be seen that some adhered foreign matter 1 a, that is, aluminum remains on the edge of the cleaning region because the flexibility of the cleaning sheet is insufficient. Further, it can be seen from the state of the scar on the probe tip 1c that the contact area is only about one third of the probe tip diameter (in this case, Φ30 μm).

  FIG. 7 shows a case where cleaning is performed by using the cleaning sheet of the first embodiment to provide a closed loop (rectangular trajectory) slippage due to the movement of the wafer table of the probing apparatus according to the second embodiment (forced contact at this time). The amount of so-called overdrive amount is 50 μm.) Is a schematic diagram of the SEM observation image of the probe tip 1c, and it can be seen that the adhered aluminum is almost completely removed from the probe tip 1c.

  In addition, since a rectangular closed-loop slip trajectory was given, polishing scratches 1d perpendicular to each other were observed on the probe tip surface. Since the polishing scratches 1d are formed orthogonally, the effect of reducing the depth of scratches by polishing has also been found. The surface roughness of the probe tip surface shown in FIG. 7 is in a mirror state less than Rmax = 0.1 μm. In a contact resistance measurement experiment performed after this, even under severe conditions of 50,000 contacts, the surface roughness is 0. It has been demonstrated that it exhibits a very stable contact resistance of 5Ω or less.

  It was also confirmed that an area range of 80% or more with respect to the probe tip diameter could be cleaned from the scar 1d by polishing. The probe card used at this time had 20 pins with an inter-probe pitch of about 200 μm, but the state as shown in FIG. 7 was confirmed for all probes. Incidentally, these series of results were obtained by SEM observation of the probe tip performed by the inventors.

  When cleaning is performed by moving the wafer table in the XY plane, the total slip amount is estimated to be 0.6 mm (slip amount 30 μm × 20 times) or more estimated from the number of cleaning operations in a general Z direction operation. Therefore, it was necessary to modify the conventional probing apparatus so as to generate the slippage.

  From the above results, the cleaning sheet of the present invention and the method for cleaning the probe tip of a probe card of a vertical type which is expected to increase in the future or a membrane type probe card in which protrusions for electrical contact are arranged in a plane are provided. A method of cleaning the wafer table by moving it is considered essential.

  As a comparison, when a conventional cleaning sheet is used and the XY wafer table 2 is moved horizontally along the probe's closed loop trajectory by the horizontal movement of the probe, the force due to the reaction received from the cleaning sheet even when the overdrive amount is about 50 μm or less. Since it is large, the frictional resistance is also increased, and it has been found that the probe shape is deformed when a slip in the lateral direction is given to the direction in which the slip naturally occurs, that is, the direction parallel to the probe.

Embodiment 4 FIG.
Next, the probe tip foreign matter removing member according to Embodiment 4 of the present invention will be described with reference to FIG. In the figure, 5c represents an overcoat film.

  As shown in the second embodiment, when the cleaning sheet according to the first embodiment is used with high polishing efficiency, foreign matter adhered to the tip of the probe, hard particles on the surface of the cleaning sheet, or binder material may fall off and cause dust generation. There is.

  Therefore, in the probe tip foreign matter removing member of the present embodiment, the soft metal overcoat film 5c is provided on the surface of the polishing layer 5 of the cleaning sheet shown in the first embodiment. By using a soft metal for the overcoat film 5c, it becomes possible to capture the dust generated during the above-described polishing with the soft metal film, and the dust generation can be effectively suppressed. Here, the soft metal refers to, for example, aluminum, copper, gold, silver or the like whose material elongation is 10% or more.

  Further, in the conventional probing apparatus, the contact with the cleaning sheet was performed with a microscope, but by providing an overcoat film 5c, which is a conductive soft metal film, on the cleaning sheet surface of the first embodiment, The contact between the probe and the cleaning sheet can be electrically detected, and a more accurate overdrive amount can be provided.

  In the present embodiment, the overcoat film 5c is formed by sputtering aluminum, and the film thickness of the aluminum is set as thin as 0.5 μm or less. This is because if the overcoat film thickness is increased, the dust generation suppressing effect is enhanced, but the polishing efficiency is lowered, so that it is necessary to set an appropriate film thickness.

  It has been experimentally confirmed that when the film thickness of the overcoat film 5c exceeds 3 μm, the polishing efficiency generally deteriorates. Further, it was confirmed that the dust generation suppressing effect is reduced when the thickness of the overcoat film 5c is less than 0.01 μm. Therefore, the effective film thickness range of the overcoat film 5c is preferably 0.01 μm or more and 3 μm or less.

  In this embodiment, aluminum is used as an example of the material of the overcoat film 5c. However, even if a metal other than aluminum is used as long as the material has a large elongation and does not significantly increase the electrical resistance, gold, silver, or copper is used. There is no problem even if other soft metals are used.

  In each of the above-described embodiments, the object to be inspected by the probe is described as a semiconductor chip for convenience. However, it goes without saying that the present invention can be similarly applied to a display device such as a liquid crystal.

It is a figure concerning Embodiment 1 of this invention, and is the figure which showed the mode of the structure of a polishing film, and the contact state of a probe. It is a figure concerning Embodiment 1 of this invention, and is the figure which showed the detail of the polishing film and probe contact. It is a figure concerning Embodiment 1 and Embodiment 2 of this invention, and is the figure shown about the concept of the overdrive of a cleaning sheet. It is a figure concerning Embodiment 2 of this invention, and is a figure shown about the locus | trajectory in case a probe slides with a cleaning sheet. It is a schematic diagram based on the SEM observation photograph of the probe tip to which aluminum adhered. It is a schematic diagram based on the SEM observation photograph of the probe tip at the time of using the conventional cleaning sheet. It is a schematic diagram based on the SEM observation photograph of the probe tip at the time of using the cleaning sheet by this invention. It is a figure related to Embodiment 3 of this invention, and is a figure showing a cross-sectional configuration of a cleaning sheet in which an overcoat for suppressing dust generation is provided on the cleaning sheet of Embodiment 1. FIG. It is the figure which showed the cleaning method by the conventional cleaning sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probe, 1a Tip adhering foreign substance, 1b Probe horizontal part, 1c Probe tip spherical surface, 1d Polishing scratch, 2 Wafer table, 3 Base plate, 4 Elastically deforming member, 4a First elastic member, 4b Second elastic member, 5 polishing layer, 5a hard particles, 5b binder material, 5c overcoat, 6a scraped foreign matter, 6b scrub mark, 10 probe card, 102 base material, 103 fine powder abrasive.

Claims (2)

A base plate, a first elastic member formed on the base plate, a second elastic member formed on the first elastic member, and hard particles formed on the second elastic member; and a polishing layer made of a binder material, the Young's modulus of the first elastic member, 5 kgf / mm ² or more 400 kgf / mm ² or less, the film thickness of the second elastic member, 0. 1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, and the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, A probe tip adhering foreign matter removing member having a particle size of the hard particles of 0.1 μm or more and 9 μm or less is installed on the wafer stage;
A probe having a tip having a substantially spherical shape or a shape having a flat portion on a part of a substantially spherical surface is slid to draw a circular or square closed loop shape on the probe tip adhered foreign matter removing member, A cleaning method for foreign matter adhering to the probe tip, wherein foreign matter adhering to the tip of the probe is removed. A base plate, a first elastic member formed on the base plate, a second elastic member formed on the first elastic member, and hard particles formed on the second elastic member; and a polishing layer made of a binder material, the Young's modulus of the first elastic member, 5 kgf / mm ² or more 400 kgf / mm ² or less, the film thickness of the second elastic member, 0. 1 μm or more and 20 μm or less, the tensile strength of the second elastic member is 0.1 kgf / mm ² or more, and the volume ratio of the hard particles to the polishing layer is 5% or more and 70% or less, A member for removing foreign matter attached to the probe tip , wherein the hard particles have a particle size of 0.1 μm or more and 9 μm or less ;
A probe whose tip has a substantially spherical shape or a shape having a flat portion in a part of the substantially spherical surface;
A wafer stage that can be moved in the horizontal direction and the vertical direction so that the probe can be slid in a circular or square closed loop shape on the probe tip adhered foreign matter removal member installed;
A probing device comprising:

Images