JP2009180620A - Device and method for testing bond strength of ic chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for nondestructively testing bond strength of a plate-like IC chip that is bonded to a circuit in a face down state, and a method for testing it. <P>SOLUTION: The device for testing bond strength of a plate-like IC chip 3 that is bonded to terminals 21, 22 of a circuit substrate 5 includes a suction board 6 for sucking a flat surface 3b opposite to the composition surface of the IC chip 3, a tube-like body 8 for connecting between the suction board and a vacuum pump, and a mechanism section 9 for fixing the tube-like body 8 to one chuck in a test device 10 by holding the tube-like body 8. The method includes the steps of fixing the tube-like body to one chuck by the mechanism section 9 by holding it by use of the test device, fixing the circuit substrate 5 to another chuck; and peeling off the IC chip 3 from the circuit substrate 5 through the tube-like body in the state that the suction board 6 is sucked to the IC chip 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an IC chip bonding strength test apparatus and a bonding strength test method. More specifically, the present invention relates to a test apparatus and a test method for testing the bonding strength of a flat IC chip that is bonded to a terminal of a circuit board in a face-down state without breaking the IC chip.

  When the test object is very small and a portion to be gripped (chucked) by a testing machine cannot be obtained, the peel strength and tensile strength tests may be difficult. In particular, recently, articles in which IC chips (semiconductor integrated circuits) are mounted on circuit boards have come to be used frequently in daily life. However, if these articles have weak IC chip bonding strength, they cannot be put into practical use. Opportunities for testing the bonding strength are increasing, and the need for confirmation by a simple test method is increasing.

Since IC chips are becoming increasingly smaller in recent years, it is particularly difficult to perform a test when they are bonded face-down (flip chip mounting) to terminals or the like of a circuit board.
An IC chip has a circuit integrated on one side of a silicon chip, and pads or bumps connecting from the circuit to an external circuit are formed on the same surface (face) side. Are bonded to the terminals of the circuit board. On the other hand, the side surface opposite to the integrated circuit surface of the silicon chip is usually a smooth surface, and a chucking portion is usually not obtained.

  When bonding the IC chip 3 to a terminal of an external circuit in a face-down state, as shown in FIG. 6, the pad or bumps 31 and 32 are fixed in contact with the terminals 21 and 22, and the periphery is sealed. 7 is performed by resin sealing and fixing. Separately, a liquid anisotropic conductive adhesive is applied between the pads or bumps 31 and 32 and the terminals 21 and 22 for connection, or a hot melt anisotropic conductive adhesive sheet is sandwiched between the pads or bumps 31 and 32 and hot pressure is applied. In some cases, connection may be made.

In order to test the IC chip 3 mounted in this manner, as described in Patent Document 1, a pole (convex protrusion) made of an adhesive is provided on the surface of the IC chip 3, and a jig is applied thereto. The peel strength may be tested by pressing from the side. However, in such a test method, there is a problem that a measured value changes at a place (height) where a jig is applied and a constant measured value cannot be obtained.
There is also a “board wiring peeling tester” as in Patent Document 2, but there is a problem that the apparatus becomes large and cannot be easily introduced due to a special apparatus.

  Further, as shown in FIG. 7, a chucking wire w or the like is fixed to a smooth surface on the back surface of the IC chip 3 with a thermosetting adhesive 18, and the wire w is chucked and pulled by a testing machine. Is also possible. However, such a test method is a so-called destructive test, and there is a problem that the tested IC chip 3 cannot be reused. In addition, for example, it is difficult to test quickly and in large quantities in the manufacturing process of a non-contact IC tag or the like.

JP 2003-106990 A JP-A-8-166340

In an article or the like mounted with an IC chip, the bonding strength with the terminal of the IC chip greatly affects the durability. Therefore, it is necessary to exclude products whose bonding strength does not meet the standard when the product is shipped.
In such a case, a conventional test apparatus or test method cannot perform quick measurement, a stable result cannot be obtained, or a test that destroys an IC chip, resulting in a decrease in production efficiency. There was a problem that wasted resources.
Therefore, the present invention has been completed by researching a test apparatus and a test method in which test results can be obtained quickly in the manufacturing process and resources are not wasted.

  A first aspect of the present invention is an apparatus for testing the bonding strength of a flat-plate IC chip bonded face-down to a terminal of a circuit board, wherein a flat surface portion opposite to the bonding surface of the IC chip is tested. An IC chip bonding strength test comprising: an adsorbing plate to be adsorbed; a tube-like body connecting the adsorbing plate and a vacuum pump; and a mechanism for fixing the tube-like body to one chuck of a test apparatus. In the device.

  In the above, if the inner diameter of the tubular body is 0.3 mm to 1.0 mm, it can be applied to a minute IC chip. In addition, if the tubular body is a plastic tube or a metal tube, it can be easily chucked to the test apparatus. Further, the flat IC chip may be mounted on the antenna of the non-contact IC tag.

  A second aspect of the present invention is a method for testing the bonding strength of a flat-plate IC chip that is bonded to a terminal of a circuit board in a face-down state. What is the bonding surface of the IC chip bonded to the terminal of the circuit board? The suction plate is fixed to the opposite flat surface portion, and the suction plate is connected to a vacuum pump by a tube-like body and vacuum suction is performed. Then, the tube-like body is fixed to one chuck of the test apparatus, The strength at the time of peeling the IC chip from the terminal of the circuit board by fixing the circuit board to the other one chuck, pulling the tube-like body in a state where the suction plate is adsorbed to the flat IC chip. There is a method for testing the bonding strength of an IC chip, which is characterized in that it is obtained.

  In the above, if the inner diameter of the tubular body is set to 0.3 mm to 1.0 mm, it can be applied to a minute IC chip. In addition, if the tubular body is a plastic tube or a metal tube, it can be easily chucked to the test apparatus. Further, the flat IC chip may be mounted on the antenna of the non-contact IC tag.

The IC chip bonding strength test apparatus of the present invention includes an adsorption board that adsorbs an IC chip with a force equal to or higher than the bonding strength. Since the IC chip can be adsorbed to the adsorption board, the bonding strength test can be performed. It becomes possible. In addition, there is no variation in measured values in the test results. Furthermore, since the test can be performed without destroying the IC chip, materials and resources are not wasted.
In the IC chip bonding strength test method of the present invention, the bonding strength of the IC chip can be rapidly tested nondestructively using the test apparatus.

  The present invention relates to a test apparatus and a test method for testing the bonding strength of a flat IC chip bonded to a circuit in a face-down state. The face-down state means that a bump or pad of an IC chip (semiconductor integrated circuit) is mounted in a so-called flip chip state so as to face the terminal of the circuit board. The circuit board is not particularly limited, and means a printed or etched wiring board having terminals to which bumps or pads of the IC chip 3 are connected. It may be a resin plate, a laminated plate, or a film. The number of bumps or pads and the number of terminals are not particularly limited.

  The IC chip 3 has a flat plate shape, and preferably has a flat surface portion 3b on the side opposite to the face surface to which the terminals 1 and 2 are joined. The size of the flat surface portion 3b depends on the outer shape of the chip, and it is difficult to ensure with a very small size IC chip, but the outer surface insertion length or outer diameter is preferably 0.5 mm to 2.0 mm or more. . In recent years, finely divided IC chips have also been used, but it is necessary to secure the suction area of the suction disk.

The IC chip 3 and the terminals 21 and 22 of the circuit board may be joined in any state. Generally, a method of fixing using an anisotropic conductive adhesive or an anisotropic conductive adhesive sheet is employed. There may be a method of simply fixing the periphery of the IC chip with a sealing resin in a state where the two are in close contact with each other. The case where both are joined by soldering or ultrasonic waves may be used.
As a typical example of such a joined state, an example in which a non-contact IC chip is connected to a terminal of an antenna coil in a non-contact IC tag can be given.

  The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a bonding strength test apparatus according to the present invention, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 3 is a perspective view showing a state in which an IC chip is adsorbed on a suction disk, FIG. 4 is a cross-sectional view of a method for fixing a terminal to which an IC chip is bonded on the circuit board side, and FIG. 5 is a plan view showing a non-contact IC tag.

  FIG. 1 is a diagram showing an embodiment of a bonding strength test apparatus of the present invention. As shown in FIG. 1, the flat surface portion 3 b opposite to the bonding surface of the IC chip 3 is sucked by the suction disk 6. The suction disk 6 is connected to a vacuum pump (not shown) through a tubular body 8. A portion close to the tubular body 8 connected to the vacuum pump may be held by the suspension means 9 as shown in the figure. Since the crosshead 12 moves only slightly when the IC chip 3 is peeled off, the measurement value is not affected even if it is held in this manner. Although the joining state between the IC chip 3 and the terminals 21 and 22 is not visible, it is assumed that they are joined as shown in FIG.

The bonding strength test apparatus 10 includes a mechanism unit 15 that holds the tube-like body 8 for connecting the suction plate 6 and the vacuum pump and fixes the tube-like body 8 to the chuck 16 of the test apparatus 10.
In the case of FIG. 1, the tubular body 8 is a small-diameter vacuum rubber hose 8g, and the mechanism portion 15 firmly holds the periphery of the vacuum rubber hose 8g. It is necessary to hold the rubber hose so that it does not slip when pulled with the rubber hose 8g. As described above, the tubular body 8 may be a rubber tube, but it is necessary to avoid a soft material that is compressed and crushed by the atmospheric pressure when vacuumed. A rubber hose reinforced with a wire spiral may be used.
The inner diameter of the tube-like body 8 is set to 0.3 mm to 1.0 mm, similarly to the inner diameter of the suction plate 6, or slightly smaller than the inner diameter. However, in the case of testing a very small IC chip of about 1 mm to 2 mm square, it is obvious that any dimension can be expanded when the IC chip 3 is large.

  The tubular body 8 itself is bent from the middle of the mechanism portion 15 and connected to a vacuum pump body (not shown). The tubular body 8 is preferably hard. The term “hard” means that it is compressed by atmospheric pressure as described above and is not crushed, and that it needs to be hard enough to expand or contract when it is held by the mechanism portion 15. Many of the commercially available vacuum rubber hoses have an inner diameter of 6 mm or more. However, in order to be applied to a micro IC chip, it is necessary to have a smaller inner diameter than a commercially available product because it is connected to a suction cup 6 having a small diameter. Not only the rubber hose but also a plastic tube, a metal tube, a ceramic tube or the like may be used.

The mechanism unit 15 is fixed to the cross head 12 via the chuck 16 and the load cell 13. The load cell 13 is a sensor that detects force (mass, torque), and detects a force when it is applied, and further converts the detected load into an electrical signal and outputs it.
The basic structure of the bonding strength test apparatus 10 includes a base 11 that chucks the circuit board 5 side of the flat IC chip 3, a cross head 12 that chucks a mechanism portion 15 that grips the tubular body 8, and the base 11 and the cross It is composed of 14 frame portions on both sides for connecting the heads 12 together. The cross head 12 is configured to move up and down along rails provided along the inside of a frame (frame body) 14. The basic structure itself of the test apparatus 10 is the same as that of a tensile tester or a so-called universal tester.

In the case of a non-contact IC tag, the bonding strength between the IC chip 3 and the terminal varies greatly depending on bonding conditions, and is often in the range of 10 to 1000 N (per chip). Therefore, it is preferable that the suction strength of the suction plate 6 that sucks the IC chip 3 is also 1000 N or more.
The acceptance criteria for bonding strength in the case of a non-contact IC tag is not uniform depending on how the IC tag is used. When the surface of the IC chip 3 is covered with a protective sheet, a reinforcing effect can be expected. When it is not covered with a protective sheet, it is necessary to have a considerable strength.

  FIG. 2 is a diagram showing another embodiment of the device of the present invention. Since the external structure of the test apparatus 10 is the same as that in FIG. 1, only the portion that holds the IC chip 3, the suction disk 6, and the tubular body 8 is illustrated. In the case of FIG. 2, the tubular body 8 is made of a metal tube or a plastic tube 8p. There is an advantage that the expansion and contraction and deformation are smaller than those of the vacuum rubber hose 8g and are not easily crushed.

  The metal tube or the plastic tube 8p has a portion 8v that rises about 1 cm to 10 cm perpendicularly from the suction plate 6 that sucks the flat surface 3b portion of the IC chip 3, and is branched in a T-shape from the end of the portion. Horizontal portions 8h1 and 8h2 are provided. The branched 8h2 side has a blunt end to block the air flow. The branched 8h1 side is connected to a vacuum pump (not shown) by a vacuum rubber hose 8g. The branching portion is provided in order to maintain the rising portion 8v vertical by adjusting the inclination with respect to the vacuum pump connection side. Therefore, you may branch in four directions instead of two directions. As shown in FIG. 1, the suspension means 9 for the rubber hose 8g may be provided. When the tubular body 8 is a metal tube or a plastic tube, the inner diameter of the tubular body 8 is set to 0.3 mm to 1.0 mm as in the case of the suction plate 6 or slightly reduced.

The mechanism 15 for holding the tubular body 8p may be pulled vertically from the tip of the rising portion 8v with a metal material as shown in FIG. 2, or from both of the substantially horizontal portions 8h1 and 8h2 branched in a T shape. You may pull. In this case, the mechanism portion 15 is only a suspended portion for fixing the tubular body 8p to the chuck 16.
The same applies to FIG. 1, but the test apparatus may be a horizontal type instead of a vertical type. In that case, of course, the sample is pulled in the horizontal direction, not the vertical direction. The circuit board 5 is attached in parallel to the base 11 and in the vertical (gravity) direction.

FIG. 3 is a perspective view showing a state in which the IC chip is adsorbed to the adsorbing board. The planar outer shape of the suction surface 6f of the suction disk 6 is circular or rectangular. The outer size of the suction disk 6 is adjusted to the size of the flat surface portion 3b of the IC chip 3, and the outer diameter φ is about 0.5 mm to 10.0 mm. It is preferably about 5 mm to 2.0 mm.
The inner diameter of the suction holes through which air is sucked is preferably in the range of 0.3 mm to 1.0 mm corresponding to the size of the outer diameter φ of the suction disk 6. The inner diameter r of the tubular body 8 is equal or slightly reduced. This is because the recent IC chip 3 is fragmented to 1.0 mm square or less, so that it can cope with a minute flat surface. The suction disk 6 is often made of silicon rubber or polyurethane rubber.

  The IC chip bonding strength test method of the present invention is performed as follows using the test apparatus 10 described above. First, the circuit board 5 in which the flat IC chip 3 is bonded to the terminals 21 and 22 in a face-down state is prepared. The suction disk 6 is fixed to a flat surface portion opposite to the bonding surface of the IC chip 3 bonded to the terminals 21 and 22 of the circuit board 5 while vacuum suction. Vacuum suction is continued in a state where the suction disk 6 is connected to the vacuum pump by the tubular body 8. The tubular body 8 is fixed to one chuck 16 of the test apparatus 10, and the circuit board 5 is fixed to another chuck on the base 11 side of the test apparatus. In a state where the suction plate 6 is attracted to the flat IC chip 3, the crosshead 12 is operated to pull the tubular body 8, and the IC chip 3 is peeled from the terminals 21 and 22 of the circuit board 5. Determine the bonding strength at the time.

  As described above, the side of the circuit board 5 facing the IC chip 3 is fixed to the chuck of the apparatus base 11. When the circuit board 5 is a rigid board that does not deform, it can be fixed as it is without any special device for fixing the chuck. However, if the circuit board 5 is made of a flexible film like a non-contact IC tag, the chuck can be used as it is. Can not. Therefore, the following is performed.

FIG. 4 is a cross-sectional view of a fixing method on the circuit board 5 side of the terminal to which the IC chip 3 is joined. The case of the non-contact IC tag 20 which consists of a flexible base material is illustrated.
4A shows a fine hole (diameter 0.5 to 1) on the back surface of the base film 5p of the non-contact IC tag 20 (the film surface opposite to the side where the IC chip 3 is mounted on the antenna 2). This is a measurement method in a state where a large number of vacuum suction plates (vacuum plates) 30 are in close contact with each other and fixed by vacuum suction.
FIG. 4B shows a state in which the back surface of the base film 5p of the non-contact IC tag 20 is adhered to the hard substrate 31 with the adhesive 17 and measured. In this method, a hard substrate 31 is fixed to the chuck of the base 11 for measurement. Also in this case, the IC chip 3 itself is not destroyed.
In FIG. 4C, the surface of the non-contact IC tag 20 is covered with a hard plate 32 having an opening 32h slightly larger than the planar shape of the IC chip 3 so that the IC tag 3 is fitted into the opening 32h. In this method, the same hard plate 33 that is not perforated is applied, and the non-contact IC tag 20 is fixed to the chuck of the base 11 while being sandwiched between both hard plates 32 and 33.
Any of such fixing methods can be employed on the circuit board 5 side.

Here, for reference, a non-contact IC tag will be described. FIG. 5 is a plan view showing a non-contact IC tag. It is the state seen through from the back side of the base film 5p which is a transparent base material in which the antenna pattern 2 is formed. In the non-contact IC tag 20, the antenna pattern 2 is formed on the base film 5 p, and the IC chip 3 is bonded to both end terminals 21 and 22 of the antenna pattern 2. In the final product, the antenna and the IC chip 3 are usually covered with a protective sheet. When FIGS. 1-4 etc. are the non-contact IC tags 20, it means the test performed before laminating a protective sheet. The conducting member 26 is a member that connects the other end of the antenna to the terminal 21 from the back side. The recent IC chip 3 has a thickness of about 100 μm to 500 μm. PET, polyimide, or the like is used for the base film 5p.
The antenna pattern 2 is shown as a planar coil in FIG. 5, but it may be a dipole antenna or a patch antenna consisting of two pieces on the left and right. Usually, it consists of a pattern in which a metal foil laminated on the base film 5p is etched or printed with conductive ink.

The test apparatus of the present invention has the simple configuration as described above, but has a feature that the bonding strength of the IC chip can be easily measured. In addition, since a test result can be obtained quickly in the manufacturing process of the product and the IC chip is not destroyed, the test apparatus does not waste resources.
In the IC chip bonding strength test method of the present invention, the bonding strength of the IC chip can be rapidly tested nondestructively using the test apparatus. It is obvious that it can be used for the bonding strength test of minute products other than IC chips.

It is a figure which shows one Embodiment of the joining strength test apparatus of this invention. It is a figure which shows other embodiment. It is a perspective view which shows the state by which the IC chip was adsorbed by the adsorption board. It is sectional drawing of the fixing method by the side of the circuit board of the terminal which an IC chip joins. It is a top view which shows a non-contact IC tag. It is a figure which shows the joining state between an IC chip and the terminal of a circuit. It is a figure which shows the conventional joining strength test method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Antenna pattern 21, 22 Terminal 3 IC chip 31,32 Pad 5 Circuit board 6 Suction board 7 Sealant 8 Tubular body 9 Suspension means 10 Bonding strength test apparatus 11 Base 12 Crosshead 13 Load cell 14 Frame 15 Mechanism part 16 Chuck 17 Adhesive 20 Non-contact IC tag

Claims (8)

An apparatus for testing the bonding strength of a flat IC chip bonded face-down to a terminal of a circuit board, the suction disk adsorbing a flat surface portion opposite to the bonding surface of the IC chip, An IC chip bonding strength test apparatus comprising: a tube-like body connecting between the suction plate and the vacuum pump; and a mechanism unit for fixing the tube-like body to one chuck of the test apparatus. 2. The IC chip bonding strength test apparatus according to claim 1, wherein the tubular body has an inner diameter of 0.3 mm to 1.0 mm. 3. The IC chip bonding strength test apparatus according to claim 1, wherein the tubular body is a plastic tube or a metal tube. 2. The IC chip bonding strength test apparatus according to claim 1, wherein the flat IC chip is mounted on an antenna of a non-contact IC tag. A method for testing the bonding strength of a flat-plate IC chip bonded face-down to a terminal of a circuit board, on a flat surface portion opposite to the bonding surface of the IC chip bonded to the terminal of the circuit board The suction disk is fixed, the suction disk is connected to a vacuum pump by a tube-like body, and vacuum suction is performed. Then, the tube-like body is fixed to one chuck of the test apparatus, and a circuit is connected to the other one chuck of the test apparatus. The IC is characterized in that the substrate is fixed, the tube-shaped body is pulled in a state where the suction plate is adsorbed to the flat IC chip, and the strength when peeling the IC chip from the terminal of the circuit board is obtained. Chip bonding strength test method. 6. The IC chip bonding strength test method according to claim 5, wherein an inner diameter of the tubular body is 0.3 mm to 1.0 mm. 7. The method of testing the bonding strength of an IC chip according to claim 5, wherein a plastic tube or a metal tube is used as the tubular body. 6. The IC chip bonding strength test method according to claim 5, wherein the flat IC chip is attached to an antenna of a non-contact IC tag.

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