JP2006054463A - Electric conduction inspection method of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive for inspection of an electronic component which can be peeled and removed at electrical conduction inspection of a high-density electrode, such as a semiconductor chip, which does not require the time or trouble, and which is economical. <P>SOLUTION: An adhesive layer, having a water absorption of 0.5% or more and consisting of the composite system of one kind of or two or more kinds of substance selected from the following (A) to (B) groups, is formed between electrodes, facing each other, at least one of which protruding from the surface of a substrate, and then, in a state in which the electrodes facing each other come into contact by an applied pressure. Both the electrodes are fixed at the adhesive layer and an electrical conduction inspection of an electronic component with unknown electrical characteristics is performed. After the inspection, the adhesive is removed from the substrate surface, including the electrode of the electronic component using water as a solvent. The material (A) is a viscous adhesive containing a surfactant or that formed in the surface layer, and the material (B) is a viscous adhesive containing a hydrophilic substance or that formed in the surface layer. The surfactant in (A) is nonionic, or the hydrophilic substance in (B) is a substance of a polar group or a deliquescent material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an energization inspection method for an electronic component having a semiconductor chip or the like and a high-density electrode.

  Conventionally, as an inspection method for an electronic component having a semiconductor chip or the like and a high-density electrode, an electrical property is measured by an instrument such as an ohmmeter from an electrode of an electronic component whose electrical property is unknown through an electrode whose electrical property is known. A current inspection method is being evaluated. The energization inspection is extremely important in terms of grasping electrical characteristics such as disconnection of the circuit of the specimen and insulation from adjacent circuits, and checking functions such as driveability and output characteristics of components.

At this time, as a method of obtaining electrical continuity between different parts, a stylus method using a probe having a contact terminal or a curable adhesive is disposed between both electrodes, and an electric current inspection is performed in an uncured or semi-cured state. There are known methods for carrying out the method, or methods using anisotropic conductive sheets whose conductors are exposed or protruded on the front or back side or one side.
Japanese Patent Laid-Open No. 3-16147

  However, the stylus method using the probe has a problem that the resolution is inadequate to cope with the recent increase in the density of electrodes, and that a fine probe is required for each terminal, resulting in an increase in cost.

  Further, the method of inspecting under a state where the adhesive is not sufficiently cured can be relatively easily performed by heat or a solvent when removing defective parts. However, if the adhesive is in an excessively cured state, peeling becomes difficult, and if the curing is insufficient, defective parts will be transferred to unexfoliated parts or plate surface contamination, which means that strict control of the cured state is required. There is a problem. Furthermore, in this method, since the curing of the uncured portion of the adhesive is accelerated by heating the component and it becomes difficult to peel off the component, a voltage is applied to an electronic component such as a semiconductor chip heated to a predetermined temperature, thereby causing an initial defective component. There is also a problem that a so-called burn-in test cannot be adopted.

  Furthermore, the method using anisotropic conductive sheets is a high resolution because the manufacture of anisotropic conductive sheets is provided with fine through-holes by, for example, laser light and a conductor is formed by plating or the like. Although the product can be obtained, the manufacturing cost is high, so there is a problem that it is expensive and difficult to put into practical use. Further, in the case of a sheet in which a conductor is formed in the electrode corresponding part, it is expensive in terms of process, for example, troublesome alignment between both electrodes and the conductor of the anisotropic conductive sheet is necessary.

  Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide an economical method of inspecting electronic parts that can be peeled and removed during energization inspection of a high-density electrode such as a semiconductor chip, and does not require time. To do.

(1) One type selected from the following groups (a) to (b) between an electrode in which at least one of the electrodes facing each other protrudes from the substrate surface and the other opposing electrode in order to achieve the above object Alternatively, an adhesive layer composed of two or more composites with a water absorption rate of 0.5% or more is formed, and then both electrodes are fixed with the adhesive layer in a state in which contact is made between the opposing electrodes by pressing. Then, an electrical current inspection of an electronic component with unknown electrical characteristics is performed, and after the inspection is finished, the adhesive is removed from the substrate surface including the electrodes of the electronic component using water as a medium.
(B) Adhesive containing surfactant or formed on surface layer (b) Adhesive containing hydrophilic substance or formed on surface layer (2) In item (1), ( The surfactant (a) is nonionic, or the (b) hydrophilic substance is a polar group-containing substance or a deliquescent substance.
The adhesive used in the present invention is capable of contacting and holding the counter electrode by pressurization, and is characterized in that the adhesive layer can be peeled off from the substrate surface including the electrode of the electronic component after the inspection is completed.

  According to the present invention, since both electrodes are brought into contact with an adhesive that can be easily peeled and removed between the electrodes facing each other, and an electric current inspection can be performed under a low resistance of only contact between the two electrodes, accurate electrical characteristics can be obtained. Judgment is possible.

  Further, since both electrodes are bonded and fixed to such an extent that they do not deviate from each other, it is possible to accurately determine the electric characteristics without any electrode deviating even when externally applied during the energization inspection.

  The adhesive layer that can be removed after completion of the inspection used in the present invention is determined in consideration of electrode contact conditions and peeling method as one or more composite systems selected from the groups (a) and (b) above. To do.

  In the case of (A) and (B), particularly when water is removed as a medium, these are preferable because they form a water-soluble layer at the adhesive interface and can be easily peeled off. In this case, it is preferable to increase the water absorption rate (JIS, K7209) of the adhesive to 0.5% or more because the peelability can be improved, and more preferably 1 to 20%.

  A typical example of the adhesive containing a surfactant or formed on the surface layer is an emulsion system in which an adhesive resin such as an acrylate ester, rubber or olefin is dispersed with a surfactant in a medium such as water. is there. As the surfactant, various anionic, nonionic, cationic, and amphoteric ones can be applied. These are preferably water-soluble when peeled off using water as a medium. In consideration of the corrosiveness of the electrode, nonionic properties such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, and polyoxyethylene acyl esters are preferable.

Examples of hydrophilic substances include alcohols, polyhydric alcohols such as glycols and glycerin, polar group-containing substances such as carboxyl groups and hydroxyl groups, or deliquescent substances such as CH ₃ COOK and CaCl ₂ .

  In addition, for example, a photocurable liquid resin having a hydrophilic group such as a polyhydric alcohol is interposed between the electrodes to obtain contact with the electrode in an uncured state, and then cured to fix the electrode by increasing the cohesive force. There is also a method of peeling after the continuity test.

  The electrode protruding from the substrate surface used in the present invention only needs to protrude even slightly from the substrate surface, and so-called bumped semiconductor chips are typical. There are also printed circuit boards having protruding electrodes such as copper foil on an insulating substrate.

  If at least one of the opposing electrodes protrudes from the substrate surface, the other opposing electrode is a concave electrode obtained by, for example, a thin film method or an additive method, as in the case of so-called planar electrodes or bumpless semiconductor chips. But you can. The electrodes of the bumpless semiconductor chips are formed in a concave shape about several microns from the surface insulating layer. In this case as well, the electrodes facing each other can be applied by protruding from the substrate surface (for example, transfer bumps).

  The method of obtaining contact of electrodes facing each other by pressurization is possible at room temperature if the peelable adhesive layer is liquid. However, when a high molecular weight material is used as a basic material, heating and ultrasonic waves are used in combination. You can also. In order to obtain contact of the electrode, the viscosity is preferably set to 100 poise or less by heating or the like.

  For example, when the adhesive layer is in the form of a film, the adhesive fixation may be improved by cooling after heating and melting, and in the case of a liquid material by crosslinking or the like to improve the cohesive force of the adhesive. Moreover, pressurization means, such as an inspection apparatus, can be used together as needed.

  In the case where the peelable adhesive layer is in the form of a film, the coating process is not required, and it can be supplied in a continuous state with a constant thickness, so that the process can be automated and effective in reducing costs. Further, for example, it can be formed in advance on a wiring board having an inspection electrode, and the circuit board with a film can be easily obtained by pasting or the like. At this time, it is preferable that the adhesive has tackiness because the positioning and temporary fixing of the electrodes are facilitated.

  Further, by adding conductive particles in the adhesive, it is possible to more efficiently obtain contact between the opposing electrodes. In this case, it should be noted that the particle size is made smaller than the distance between adjacent electrodes, and the addition amount is set to 15% by volume or less, preferably 12% by volume or less so as not to cause a short circuit with the adjacent electrode.

After the energization inspection, by removing the adhesive layer from the substrate surface including the electrodes, only normal products can be mounted on the substrate in the next process. In this case, it is preferable that the peeling strength is 5 kg / cm ² or more, preferably 15 kg / cm ² or more because the film can be easily handled in a peelable state.

  As a mounting method, a general method such as so-called flip chip or wire bonding can be adopted. However, since the conduction test using the adhesive of the present invention is performed in the previous process, the same process or material should be used. For example, a bonding method using an adhesive such as an epoxy is preferable because the operation can be simplified.

  It is preferable to add conductive particles to the adhesive layer, as in the case of the above-described removable adhesive layer, because it is easy to obtain contact with the opposite electrode, but it is always necessary if contact with the electrode is possible. Not.

  According to the present invention, an adhesive layer that can be removed after the inspection process is formed between an electrode in which at least one of the opposing electrodes protrudes from the substrate surface and the other opposing electrode, and the electrodes are opposed when pressed. The adhesive layer is flow-excluded from the part, and contact between the electrodes is obtained, and in this state, both electrodes are bonded and fixed to such an extent that they do not shift. For this reason, an electrical current inspection can be performed under a low resistance of only contact between both electrodes, and thus accurate electrical characteristics can be determined. Further, since both electrodes are bonded and fixed to such an extent that they do not deviate from each other, it is possible to accurately determine the electric characteristics without any electrode deviating even when externally applied during an energization inspection.

  Since the adhesive of the present invention uses an adhesive layer that can be removed after the inspection process, it can also be applied under heating conditions such as a burn-in test. After the energization inspection, the normal product can be mounted on the substrate by peeling and removing the adhesive layer from the substrate surface including the electrodes, so that the process is simple. In the case of mounting using an adhesive bonding method, the same process and organic adhesive material as those used in the electric current inspection can be used, so that cost reduction and improved reliability can be obtained.

  According to the present invention, it is possible to conduct an energization inspection by aligning an electrode in which at least one of the opposed electrodes protrudes from the substrate surface and the other opposing electrode. Therefore, even in the case of a large area such as a semiconductor wafer having a protruding electrode, it can be dealt with only by preparing a circuit board corresponding to this, so that low-cost inspection is possible. As a circuit board in this case, there is an advantage that a planar electrode that can be easily processed with high definition can be adopted.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to the Example described below.

  First, a first embodiment of the present invention will be described.

  IC chip (2 × 10 mm, thickness 0.5 mm, 4 sides, 50 μm square, 20 μm high gold electrodes called bumps are formed on the sides, polyimide insulating film on the surface other than the bumps And a conductively inspected glass electrode (a thin film circuit of Ni / Au = 0.5 / 0.1 μm is formed on a 1.1 mm thick glass corresponding to the size of the bump electrode of the IC chip). Then, a peelable adhesive layer described below was formed between the glass periphery and a planar electrode having a measurement pad extending as a lead on the periphery of the glass and expanding the circuit width of the peripheral portion to 200 μm.

  An acrylic adhesive (Tg 35 ° C, molecular weight 500,000, self-crosslinking type, containing nonionic surfactant) emulsion (solid content 45%) is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 µm) with a roll coater. And dried at 120 ° C. for 20 minutes to obtain a crosslinked adhesive film having a thickness of 20 μm. The water absorption rate (JIS, K7209) of this film was 2.4%.

This film was attached to the IC chip mounting portion on the glass electrode, the separator was peeled off, the IC chip was placed and the electrode was aligned, and then heated and pressurized at 50 ° C., 20 kgf / mm ² for 5 seconds. With respect to this connection body, it was possible to inspect an uninspected IC chip using a glass electrode lead. In addition, the energization inspection is more effective by performing under pressure using a silicone rubber cushioning material attached to a socket device for TAB inspection on the market, and burn-in in which 5 volts is applied by heating at 100 ° C. using this device. Evaluation was also possible.

  When the connected body after completion of the energization test was immersed in pure water at 70 ° C. for 10 minutes, the film was peeled cleanly from the glass electrode and the IC chip.

Thereafter, the IC chip is washed and dried with pure water and ethanol, and anisolum AC-7144 (anisotropic conductive film, resolution 14 / mm, plastic with a particle size of 5 μm on epoxy thermosetting adhesive) is used for glass electrodes for liquid crystal panels. When it was connected at 160 ° C., 30 kgf / mm ² , for 15 seconds with a conductive particle plated on, a product name of Hitachi Chemical Co., Ltd.), good display characteristics were obtained.

  In this example, it is considered that the surfactant contained in the emulsion-type acrylic adhesive system was immersed in heated pure water, thereby reducing the interfacial force and making it peelable. In addition, the position of the electrode was easy due to the tack of the adhesive. Furthermore, the connection can be performed at a relatively low temperature of 160 ° C. by using the same process and organic material as in the current inspection.

  Next, a second embodiment will be described. In this second embodiment, the peelable adhesive layer was changed, but the other conditions were the same as in the first embodiment.

  A composition composed of 100 parts by weight of acrylic rubber (Tg 10 ° C., molecular weight 600,000, containing 2% carboxyl group as a functional group) and 2 parts of methylated melamine was dissolved in toluene, and then formed on a separator, 120 ° C. for 10 minutes It dried and obtained the 10-micrometer-thick adhesive film. The separator of this film was peeled off, and a surface treatment was performed by uniformly spraying a 1% methanol solution of glycerin on the surface. When evaluated in the same manner as in the first example, it was possible to inspect the energization of the IC chip, and subsequent peeling and connection with an adhesive were also good. In this example, since glycerin is water-soluble, waste water treatment after peeling is easy, and cleaning at the time of connection is easy.

In the third embodiment, a photocurable resin (25 ° C. viscosity, 20 poise) composed of 100 parts by weight of polyethylene glycol diacrylate, 3 parts of benzophenone and 1 part of Michler's ketone is formed on the IC chip mounting part on the glass electrode by a dispenser. Then, after placing the IC chip and aligning the electrodes, ultraviolet rays were irradiated (1 J / cm ² ) from the lower surface of the glass and cured. Also in this case, the IC chip was inspected for current, and the subsequent peeling and connection with an adhesive were also good.

  In this example, since the material was liquid, the viscosity was low, and electrode contact was obtained at room temperature. In addition, it was simple because there was no process for peeling the separator, and when a light-impermeable layer was formed on a transparent circuit board, curing of unnecessary parts was sweetened during curing, and peeling was further facilitated.

  In the fourth example, the Tg of the pressure-sensitive adhesive mainly composed of 13 carbon atoms of the ester is set to around room temperature, and a mixed solvent type acrylic pressure-sensitive adhesive (Tg 25 ° C., molecular weight 1.1 million) of n-heptane / methyl ethyl ketone is used. The conditions were the same as in the first example. In this case as well, the IC chip was inspected for energization and the peeling was good thereafter.

  In this example, since Tg was near room temperature, electrode contact was obtained by heating at 40 ° C., and peeling was easy under an environment of 10 ° C. Furthermore, in the case of this Example, since the molecular weight was large and the film was peeled off at a temperature of Tg or less, no transition occurred at the time of peeling even without crosslinking. Moreover, since Tg acts like a melting point and the temperature activity is sharp, it becomes possible to make the temperature difference between sticking and peeling slight.

In the fifth example, 1% by volume of conductive particles plated on a plastic having a particle size of 5 μm was added, and other conditions were the same as in the first example. In this example, conduction was obtained at a relatively low pressure at 50 ° C., 5 kgf / mm ² , 5 seconds, heating and pressurization, and an energization test was possible. Moreover, since the cohesive force of the adhesive is large, it is easy to peel off, and the conductive particles do not fall off from the pressure-sensitive adhesive, and can be recovered from the water after peeling with a filter and reused.

In the sixth example, the conductive particles of the above-mentioned Anisol AC-7144 were not added as an adhesive, and other conditions were the same as those in the first example. In the case of this example as well, it was possible to inspect the energization by contacting both electrodes, the subsequent peeling and the connection with an adhesive were good, and a connection with excellent reliability by adhesion fixation was obtained.

Claims (2)

Water absorption comprising one or two or more composite systems selected from the following groups (a) to (b) between an electrode in which at least one of the opposing electrodes protrudes from the substrate surface and the other opposing electrode An electronic component with an unknown electrical characteristic is formed by forming an adhesive layer with a rate of 0.5% or more, and then fixing both electrodes with the adhesive layer in a state in which contact is made between the opposing electrodes by pressing. An electronic component energization inspection method comprising: removing an adhesive from a substrate surface including an electrode of an electronic component using water as a medium after completion of the inspection.
(B) Adhesive containing surfactant or formed on surface layer (b) Adhesive containing hydrophilic substance or formed on surface layer The method of claim 1, wherein the surfactant in (a) is nonionic, or (b) the hydrophilic substance is a polar group-containing substance or a deliquescent substance.