JPH07294585A - Electric continuity inspection method of electronic parts - Google Patents

Abstract

PURPOSE:To provide an economical adhesive for inspecting electronic parts without requiring much labor and time which can be peeled and eliminated when performing the conduction inspection of a high-density electrode such as a semiconductor chip. CONSTITUTION:An adhesive layer which can be eliminated after an inspection process is formed between an electrode where at least one of opposing electrodes protrudes from a substrate surface and the other opposing electrode, and then is pressed to cause a surplus adhesive layer to flow out to be eliminated from the opposing electrode part and, at the same time, the electrodes to obtain contact state with each other. Both electrodes are adhered and fixed so that they do not deviate in that state and then a conduction inspection is performed. then, the adhesive layer is eliminated from a substrate surface containing the electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting electrical conduction of electronic parts having semiconductor chips and high density electrodes.

[0002]

2. Description of the Related Art Conventionally, as a method of inspecting an electronic component having a semiconductor chip or the like and a high-density electrode, an electrode of an electronic component whose electrical characteristic is unknown is passed through an electrode whose electrical characteristic is known, and a resistance meter, etc. An electric current inspection method for evaluating electric characteristics by a measuring instrument is performed. The energization inspection is extremely important from the viewpoints of grasping the electrical characteristics such as the disconnection of the circuit of the test piece and the insulation with the adjacent circuit, and the function check such as the driveability and output characteristics of the parts.

At this time, as a method for obtaining electrical continuity between different parts, a stylus method using a probe having a contact terminal or a curable adhesive is placed between both electrodes to obtain an uncured or semi-cured state. There is known a method of conducting an electric current inspection, or a method of using anisotropically conductive sheets in which a conductor is exposed or projected on the front and back or one surface.

[0004]

However, the stylus method using the above probe is expensive because it cannot cope with the recent high density of electrodes and lacks resolution and requires a fine probe for each terminal. There's a problem.

Further, the method of inspecting under the condition where the adhesive is not sufficiently cured can be relatively easily carried out by using heat or a solvent when removing defective parts. However, if the adhesive is hardened excessively, peeling becomes difficult, and if the adhesive is insufficiently hardened, strict control of the hardened state is necessary because defective parts may migrate to unpeeled parts or plate surface contamination. There is a problem. Furthermore, in this method, by heating the component, the curing of the uncured portion of the adhesive is promoted and peeling of the component becomes difficult, so a voltage is applied to an electronic component such as a semiconductor chip heated to a predetermined temperature to cause an initial defective component. There is also a problem that the so-called burn-in test cannot be adopted.

Further, the method of using anisotropically conductive sheets is such that the anisotropically conductive sheets are manufactured by forming fine through holes with, for example, a laser beam and forming conductors thereon by plating or the like. However, although a high-resolution product can be obtained, the manufacturing cost becomes high, and 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 portion, it is necessary to perform troublesome alignment between both electrodes and the conductor of the anisotropic conductive sheet, which makes the process expensive.

Therefore, the present invention has been made to solve the above-mentioned problems, and provides an economical method for conducting electricity inspection of electronic parts, which can be removed by peeling and removing for electricity inspection of high density electrodes such as semiconductor chips. To the purpose.

[0008]

In order to achieve the above object, the following (a) to (b) are provided between an electrode in which at least one of the electrodes facing each other protrudes from the substrate surface and the other opposing electrode.
An adhesive layer made of a composite system of one or more selected from the group (d) is formed, and both electrodes are fixed in a state of contacting the electrodes facing each other by pressurization, and the electrical characteristics are A feature of the present invention is that an unknown electronic component is inspected for electricity, and after the inspection is completed, the adhesive layer is removed from the surface of the substrate including the electrodes of the electronic component. (A) Adhesive containing a surfactant or formed on the surface layer (b) containing a hydrophilic substance or forming an adhesive on the surface layer (c) containing a peeling agent or forming a surface layer Adhesive adhesive formed (d) Adhesive adhesive having a glass transition point near room temperature The adhesive used in the present invention can contact and hold the counter electrode by pressurization, and after completion of the inspection, the electrode of the electronic component It is characterized in that the adhesive layer can be peeled and removed from the surface of the substrate including. The method of removal is preferably peelable at room temperature, but heating, ultrasonic waves, forced agitation, irradiation with energy rays such as ultraviolet rays and electron beams, immersion in water or a solvent, and spraying can be applied alone or in combination.

The adhesive layer that can be removed after the inspection used in the present invention is one or more composite systems selected from the above groups (a) to (d), and the contact conditions of the electrodes and the peeling method are taken into consideration. And decide.

Of these, the cases (a) and (b) are preferable, especially when water is removed as a medium, 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 agent to 0.5% or more because the releasability can be improved, and it is more preferably 1 to 20%.

In the case of (c) and (d), it is possible to peel and remove in air. In the case of (c), the surface tension of the adhesive interface is lowered to facilitate peeling. In the case of (d), it becomes hard and brittle below the glass transition point (hereinafter referred to as Tg), and T
By utilizing the property of the polymer that is softened at g or more, the conditions of contact and peeling of the electrode are satisfied.

The tacky adhesive containing a surface active agent or formed in the surface layer is an emulsion prepared by dispersing an acrylic acid ester or an adhesive resin such as rubbers or olefins in a medium such as water with a surface active agent. The system is typical. As the surfactant, anionic, nonionic, cationic,
Various types of both sexes can be applied. It is preferable that these are water-soluble when peeling using water as a medium. Further, in consideration of the corrosiveness of the electrode, it is preferably nonionic such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, and polyoxyethylene acyl esters.

As the hydrophilic substance, alcohols, polyhydric alcohols such as glycol and glycerin, polar group-containing substances such as carboxyl group and hydroxyl group, or C
Examples include deliquescent substances such as H ₃ COOK and CaCl ₂ .

Further, for example, a photocurable liquid resin having a hydrophilic group such as polyhydric alcohol is interposed between the electrodes to obtain contact with the electrodes in an uncured state, and then cured to increase cohesive force. There is also a method in which the electrodes are fixed and then peeled off after the continuity test.

Typical examples of the release agent are low surface tension substances such as silicone and fluorine, and those having a surface tension of 35 dyn / cm or less are preferable.

Examples of the adhesive having Tg around room temperature (0 to 50 ° C., preferably 15 to 35 ° C.) include acrylic acid esters which can be arbitrarily set by copolymerization of monomers having different Tg. In particular, when the ester has a long-chain form having 12 or more carbon atoms, Tg acts like a melting point, so that temperature activity becomes sharp and a temperature difference between pasting and peeling can be made small, which is preferable.

The electrode projecting from the substrate surface used in the present invention is only required to project slightly from the substrate surface, and so-called bumped semiconductor chips are typical. There is also a printed circuit board having protruding electrodes such as copper foil on an insulating substrate.

If at least one of the electrodes facing each other is projected from the surface of the substrate, the other opposing electrodes are, for example, so-called flat electrodes and bumpless semiconductor chips obtained by a thin film method or an additive method. A concave electrode may be used. The electrodes of the bumpless semiconductor chips are formed in a concave shape of about several microns from the surface insulating layer, but in this case as well, the electrodes facing each other can be applied by projecting from the substrate surface (for example, transfer bumps or the like).

The method of contacting the electrodes facing each other by pressurization can be carried out at room temperature as long as the peelable adhesive layer is liquid, but when a high molecular weight material is used as a basic material, heating or ultrasonic wave is used. Can also be used together. In order to obtain contact with the electrodes, it is preferable to set the viscosity to 100 poise or less by heating or the like.

The adhesive fixing may be carried out by, for example, improving the cohesive force of the adhesive by cooling after heating and melting when the adhesive layer is in the form of a film and by crosslinking in the case of a liquid material. If necessary, a pressurizing means such as an inspection device can be used together.

When the peelable adhesive layer is in the form of a film,
Since the coating process is not required and the product can be continuously supplied with a constant thickness, the process can be automated, which is effective for cost reduction. Further, it can be formed in advance on a wiring board having an inspection electrode, for example, and the circuit board with film can be easily obtained by pasting or the like. At this time, it is preferable that the adhesive has tackiness because the electrodes can be easily aligned and temporarily fixed.

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

By removing the adhesive layer from the surface of the substrate including the electrodes after the electric current inspection, only normal products can be mounted on the substrate in the next step. At this time, the peelable condition is that the peeling strength is 5 kg / cm ₂ or more, preferably 15 kg / cm _2.
When it is at least ₂ cm ₂ , peeling in a film state that is easy to handle is possible, which is preferable.

As a mounting method, a general method such as so-called flip chip or wire bonding can be adopted. However, since the continuity test is performed by the adhesive of the present invention in the previous step, the same steps and materials are used. It is preferable to use a bonding method using an adhesive such as an epoxy resin because the work can be simplified.

Like the above-mentioned removable adhesive layer, it is preferable to add conductive particles to the adhesive layer, because it is easy to obtain contact with the electrodes facing each other, but contact with the electrodes is possible. If not necessary.

[0026]

According to the present invention, an adhesive layer which can be removed after the inspection step is formed between at least one of the electrodes facing each other and the other of the electrodes protruding from the substrate surface and the other facing electrode. The flow of the adhesive layer is eliminated from the facing electrode portion, the electrodes are brought into contact with each other, and in that state, the two electrodes are adhesively fixed to such an extent that they do not shift. For this reason, since the energization inspection can be performed under the low resistance of only the contact of both electrodes, it is possible to accurately determine the electrical characteristics. Further, since both electrodes are bonded and fixed to the extent that they do not shift, even if pressure is applied from the outside during the energization test, there is no displacement of the electrodes, and accurate electrical characteristics can be determined.

Since the adhesive of the present invention uses an adhesive layer that can be removed after the inspection step, it can be applied even under heating conditions such as a burn-in test. After the current-carrying inspection, by removing the adhesive layer from the surface of the substrate including the electrodes of the normal product, only the normal product can be mounted on the substrate, so that the process is simple. When the mounting is a bonding method using an adhesive, the same process as that for the current inspection and the organic adhesive material can be used, so that the cost can be reduced and the reliability can be improved.

According to the present invention, the conduction inspection can be performed by aligning the electrode in which at least one of the electrodes facing each other protrudes from the surface of the substrate and the other facing electrode. Therefore, even in the case of a large area such as a semiconductor wafer having a protruding electrode, it is possible to deal with it by simply preparing a circuit board corresponding to it, so that a low cost inspection can be performed. As a circuit board in this case, there is an advantage that a plane electrode that can be easily processed with high precision is adopted.

[0029]

EXAMPLES The present invention will now be described in detail based on examples, but the present invention is not limited to the examples described below.

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

An IC chip (2 × 10
mm, thickness 0.5 mm, 5 around the four sides called bumps
200 gold electrodes of 0 μm square and 20 μm in height are formed. A polyimide insulating film is formed on the surface other than the bump portion, and a glass electrode whose conductivity has been tested (1.1 / mm thick glass is Ni /
A thin film circuit of Au = 0.5 / 0.1 μm is formed corresponding to the size of the bump electrode of the IC chip, and has a measurement pad that extends as a lead on the periphery of the glass and expands the circuit width of the peripheral portion to 200 μm. A peelable adhesive layer described below was formed between the adhesive layer and the flat electrode.

Acrylic adhesive (Tg 35 ° C., molecular weight 5
An emulsion liquid (solid content: 45%) of 0,000, self-crosslinking type, containing a nonionic surfactant was used as a separator (silicone-treated polyethylene terephthalate film, thickness 40).
μm) was coated 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 electrodes were aligned, and then 50 ° C. and 20 kg.
It was heated and pressed at f / mm ₂ for 5 seconds. With respect to this connection body, it was possible to carry out an electrical inspection of an uninspected IC chip using a glass electrode lead. In addition, the current test is a commercially available TAB
It is more effective to perform under pressure using a silicone rubber cushion material attached to the socket device for inspection, and burn-in evaluation in which 5 V is applied by heating at 100 ° C. using this device was also possible.

After the completion of the electric current inspection, the connection body was immersed in pure water at 70 ° C. for 10 minutes, whereby the film was peeled off from the glass electrode and the IC chip.

After that, the IC chip was washed with pure water and ethanol and dried, and anisorum AC-7144 (anisotropic conductive film, resolution 14) was formed on the glass electrode for the liquid crystal panel.
Book / mm, containing conductive particles plated with epoxy thermosetting adhesive on a plastic having a particle size of 5 μm, trade name of Hitachi Chemical Co., Ltd.) 160 ° C., 30 kgf / mm ₂ , 1
When connected in 5 seconds, good display characteristics were obtained.

In this example, it is considered that the surfactant contained in the emulsion type acrylic pressure-sensitive adhesive was immersed in the heated pure water to reduce the interfacial force and enable the peeling. In addition, the tack of the pressure-sensitive adhesive facilitated the alignment of the electrodes. Further, the connection can use the same process as that for the electric current inspection and the organic material, and the connection work at a relatively low temperature of 160 ° C. was possible.

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.

Acrylic rubber (Tg 10 ° C., molecular weight 60
100 parts by weight of a functional group containing 2% of a carboxyl group) and 2 parts of methylated melamine are dissolved in toluene and then formed on a separator, dried at 120 ° C. for 10 minutes, and an adhesive having a thickness of 10 μm. I got a film. The separator of this film was peeled off, and a 1% methanol solution of glycerin was uniformly sprayed on the surface for surface treatment. When evaluated in the same manner as in the first example, it was possible to carry out an electric current inspection of the IC chip, and the subsequent peeling and connection with an adhesive were also good. In this example, since glycerin was water-soluble, wastewater treatment after peeling was easy, and cleaning at the time of connection was easy.

Next, a third embodiment will be described. In the third embodiment, a condensation type silicone release agent is used in place of the glycerin, and the release after the electric current test is performed at room temperature (25
C.). Other conditions were the same as those in the second embodiment.

The surface tension of the film surface after the surface treatment is 3
It was 2 dyn / cm (JIS, K6768). In this case as well, it was possible to inspect the electric conduction of the IC chip, and the subsequent peeling was also good. In this example, by setting the surface tension of the film surface to 32 dyn / cm, peeling at room temperature in the atmosphere was possible, so the work was easy. Since the silicone release agent was cross-linked with the adhesive, it did not migrate to the electrode surface and there was no problem in connection.

In the fourth embodiment, 100 parts by weight of polyethylene glycol diacrylate and benzophenone 3 are used.
Part, photocurable resin consisting of 1 part of Michler's ketone (25 ° C
Viscosity, 20 poise) is formed on the glass electrode on the IC chip mounting part with a dispenser, the IC chip is placed and the electrodes are aligned, and then ultraviolet rays are irradiated from the lower surface of the glass (1
J / cm ² ) and cured. In this case as well, it was possible to carry out an electric test of the IC chip, 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 contact of the electrodes was obtained at room temperature. In addition, the step of peeling the separator was simple, and when the light-impermeable layer was formed on the transparent circuit board, the unnecessary portion was hardened during curing, and peeling became easier.

In the fifth embodiment, the ester has 13 carbon atoms.
The Tg of the pressure-sensitive adhesive mainly composed of is around room temperature, and it is an acrylic pressure-sensitive adhesive of mixed solvent system of n-heptane / methyl ethyl ketone (Tg 25 ° C., molecular weight 1.1 million), and other conditions are the first
The same as in the example. In this case as well, it was possible to carry out an electric conduction inspection of the IC chip, and the peeling was good after that.

In this embodiment, since Tg is near room temperature, 4
Contact of the electrodes was obtained by heating at 0 ° C, and peeling was easy under an environment of 10 ° C. Further, in the case of this example, since the molecular weight was large and peeling was carried out at a temperature of Tg or lower, migration did not occur during peeling even without crosslinking. Further, since Tg acts like a melting point and the temperature activity is sharp, it is possible to make the temperature difference between pasting and peeling small.

In the sixth embodiment, 1% by volume of conductive particles plated on plastic having a particle diameter of 5 μm was added, and the other conditions were the same as in the first embodiment. In this example, 50 ° C., 5
It was possible to conduct electricity at a relatively low pressure by heating and pressurizing at a pressure of kgf / mm ² , 5 seconds, and it was possible to carry out an electrical inspection. Further, since the adhesive has a large cohesive force, it can be easily peeled off, the conductive particles do not fall off from the pressure-sensitive adhesive, and it was possible to collect and reuse from the water after peeling with a filter.

The seventh embodiment is based on the above Anisorum AC-71.
The surface of No. 44 was treated with the condensation type silicone release agent as in the third example, and the other conditions were the same as in the first example. In this example, heating and pressing were performed at 80 ° C., 5 kgf / mm ² , and 5 seconds. In the case of this example as well, it was possible to carry out an electric current inspection, and it was possible to peel at room temperature with a release agent even though it was a curable adhesive.

In the eighth embodiment, the conductive particles of Anisolum AC-7144 described above were not added as an adhesive, and the other conditions were the same as in the first embodiment. In the case of this embodiment as well, it is possible to conduct an electric current test by contacting both electrodes, and the subsequent peeling and connection with an adhesive are also good, and a connection with excellent reliability by adhesive fixation was obtained.

[0048]

As described above, according to the present invention, both electrodes are brought into contact with each other with an adhesive that can be easily peeled and removed from the electrodes facing each other, and only a contact between the both electrodes is performed under low resistance. Since the energization inspection can be performed, it is possible to accurately determine the electrical characteristics.

Further, since both electrodes are adhered and fixed to the extent that they do not shift, even if pressure is applied from the outside during the energization inspection, there is no displacement of the electrodes and it is possible to accurately determine the electrical characteristics.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/66 S 7630-4M

Claims (1)

[Claims] 1. One or two or more kinds selected from the following groups (a) to (d) are provided between an electrode in which at least one of the electrodes facing each other protrudes from the substrate surface and the other facing electrode. An adhesive layer consisting of a composite system is formed, and both electrodes are fixed in a state where contact between the electrodes facing each other is obtained by pressurization, and an electric component is inspected for electrical characteristics. A method for inspecting electrical conduction of an electronic component, characterized in that the adhesive layer is removed from the surface of the substrate including the electrode. (A) Adhesive containing a surfactant or formed on the surface layer (b) containing a hydrophilic substance or forming an adhesive on the surface layer (c) containing a peeling agent or forming a surface layer Formed adhesive / adhesive (d) Adhesive / adhesive with glass transition temperature around room temperature