JP2011249527A - Circuit module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform electrical inspection before and after an electrode of a liquid crystal panel and an output terminal of a circuit module are crimped.SOLUTION: A circuit module 1 comprises a flexible printed circuit board 6 having a crimp region 5 where an output terminal 4 to be crimped to an electrode of a liquid crystal panel substrate is provided, and an input terminal 2; and an IC chip 7 mounted on the surface of the printed circuit board 6 on the side of the crimp region 5 and electrically connected with the input terminal 2 and the output terminal 4. A test pad 8 to be electrically connected with the output terminal 4 is provided on the surface of the printed circuit board 6 on the side opposite to the side where the IC chip 7 is mounted.

Description

  The present invention relates to a circuit module.

  In recent years, when an IC chip for driving a liquid crystal panel is mounted on the liquid crystal panel, a circuit module using a COF (Chip On Film) wiring board that can be easily processed into an arbitrary shape has been used. In addition, with the recent increase in size and quality of liquid crystal panels, the number of output signals from the IC mounted on the liquid crystal panel has increased, and the wiring of circuit modules used when mounting IC chips on the liquid crystal panel has also increased. There is a strong demand for miniaturization and high precision.

  In general, a COF wiring board includes an inner lead connected to an IC chip, an outer lead that is arranged in parallel with one end surface of the board and serves as an output terminal that is connected to a liquid crystal panel substrate, a wire breakage and short circuit check, And a test pad for performing an operation test of the mounted IC chip.

  To mount the IC chip on the liquid crystal panel, first, the inner lead and the electrode of the IC chip are joined, and the IC chip is mounted on the COF wiring board. Next, resin sealing is performed on the COF wiring board on which the IC chip is mounted in order to protect the IC chip and the joint. Then, after the operation test of the IC chip is performed, the test pad is cut and removed together with unnecessary portions by die punching or the like, and the circuit module is formed into individual pieces.

  Thereafter, the output terminal of the separated circuit module and the electrode of the liquid crystal panel substrate are pressure-bonded by using an ACF (Anisotropic Conductive Film) to thereby electrically connect the output terminal and the liquid crystal panel substrate. The circuit module on which the IC chip is mounted is mounted on the liquid crystal panel by performing simultaneous connection and adhesion simultaneously (see, for example, Patent Document 1).

  Then, a backlight or the like is incorporated into the liquid crystal panel on which the circuit module having the IC chip is mounted, and after forming the liquid crystal module, a signal is input to the input terminal of the circuit module, whereby a predetermined image is input to the liquid crystal panel. It is checked whether or not is displayed.

  Therefore, in order to improve the yield of the liquid crystal module, before and after crimping the electrodes of the liquid crystal panel and the output terminals of the circuit module, the malfunction of the IC chip due to the defect of the IC chip or the defective mounting of the IC chip is inspected. It is desired to conduct an electrical inspection.

JP 2009-194058 A

  However, in the conventional circuit module, the test pad is removed when forming the individualized circuit module, so that the IC chip is properly operated before crimping the electrode of the liquid crystal panel and the output terminal of the circuit module. It is difficult to perform an electrical test of whether or not it operates.

  Further, terminals are formed at a pitch of 50 to 70 μm in accordance with the bump pitch of the IC chip at the IC chip crimping portion of the circuit module, and terminals are formed at a pitch of 300 μm or less at the liquid crystal panel crimping portion. When electrical inspection is performed by bringing an inspection probe into contact with the output terminal of the circuit module before crimping, the output probe is also formed with the miniaturization of the electrodes on the liquid crystal panel substrate. It is difficult to make it contact.

  In addition, when the inspection probe is brought into contact with the output terminal, the crimped surface on which the output terminal is formed is deformed, scratched, or the like representing a defect called a so-called dent. There is also a possibility that the yield will decrease.

  In addition, since the terminal pitch is fine, there is a case where it is unavoidable to carry out only an appearance inspection without performing an electrical inspection. In this case, the ability to detect defective products is clearly reduced.

  In addition, when the electrodes of the liquid crystal panel and the output terminals of the circuit module are pressure-bonded and an electrical inspection is performed on the liquid crystal module in which a backlight or the like is incorporated, the liquid crystal module is not suitable for reasons such as an IC chip mounting failure. When it is a non-defective product, there is a disadvantage that the loss increases.

  In order to eliminate such inconveniences, an object of the present invention is to provide a circuit module capable of performing an electrical test before and after crimping the electrodes of a liquid crystal panel and the output terminals of the circuit module.

  The circuit module of the present invention is mounted on a surface of the flexible printed circuit board on the side of the pressure-bonding region, the flexible printed circuit board having a pressure-bonding region and an input terminal provided with an output terminal to be crimped to an electrode of the liquid crystal panel substrate, and the input And an IC chip electrically connected to the output terminal, and a test pad electrically connected to the output terminal is provided on a surface opposite to the surface on which the IC chip is mounted. And

  According to the present invention, since the test pad that is electrically connected to the output terminal is provided on the surface opposite to the surface on which the IC chip of the circuit module is mounted, the output terminal connected to the electrode of the liquid crystal panel substrate; A signal output from the IC chip can be obtained from the IC chip via the test pad.

  Therefore, it is possible to perform an electrical test as to whether or not the IC chip operates normally before the electrodes of the liquid crystal panel substrate and the output terminals of the circuit module are pressure-bonded using the signal obtained through the test pad. . Thereby, the yield of the liquid crystal panel on which the circuit module is mounted can be improved.

  In addition, even after the electrodes of the liquid crystal panel substrate and the output terminals of the circuit module are pressure-bonded, the electrical inspection can be performed using the signal acquired through the test pad. Therefore, since the electrical inspection can be performed without forming a liquid crystal module in which a backlight or the like is incorporated in a liquid crystal panel on which the circuit module is mounted, the yield of the liquid crystal module can be improved.

  In addition to confirming simple operation of the IC chip, it is possible to detect the drive signal waveform supplied directly to the liquid crystal panel, and also the fluctuation of the drive signal in a loaded state by connecting the liquid crystal panel. It is possible to electrically detect and determine a slight decrease in electrical characteristics that is difficult to detect in a lighting test, a short circuit in a liquid crystal panel, and the like, thereby improving yield and inspection throughput.

  Furthermore, since the test pad is provided on the surface opposite to the surface on which the IC chip is mounted as well as having the crimping region where the output terminal is provided and the input terminal, an electrical test is performed by bringing the inspection probe into contact with the output terminal. However, it is possible to prevent deformation, scratches, etc. from occurring in the crimping region. Therefore, it is possible to prevent a decrease in yield due to deformation of the IC chip mounting surface.

  In the circuit module of the present invention, it is preferable that the test pads are arranged in a staggered manner in a region on the surface opposite to the crimping region.

  According to the test pads arranged in a staggered manner in the back surface area of the circuit module opposite to the crimping area, test pads corresponding to the output terminals can be easily formed on the back surface even if the adjacent output terminals are narrow. . Furthermore, since the test pad is disposed in the region on the surface opposite to the crimping region, a crimping region including an output terminal having a predetermined terminal width can be easily formed.

  In the circuit module of the present invention, it is preferable that a blind via for electrically connecting the output terminal and the test pad is provided.

  According to the blind via that electrically connects each output terminal and the test pad, a test pad corresponding to each output terminal can be formed, and the space between the output terminals and between the test pads can be further reduced. Therefore, it is possible to reduce the size of the circuit module including the crimping region and the region where the test pad is disposed.

The figure which shows the mounting surface of the circuit module of this embodiment. The figure which shows the back surface of the mounting surface of the circuit module of this embodiment. FIG. 3 is an enlarged view of the test pad 8 of FIG. 2 and its peripheral part. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. The expanded sectional view of the blind via 9 vicinity of the circuit module of this embodiment.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  As shown in FIG. 1, the circuit module 1 of this embodiment includes an input terminal portion 3 in which input terminals 2 are arranged and an output terminal portion 5 in which output terminals 4 that are crimped to electrodes of a liquid crystal panel substrate (not shown) are arranged. The flexible printed circuit board 6 (corresponding to the crimping region of the present invention) and the input terminal section 3 and the output terminal section 5 of the flexible printed circuit board 6 are mounted on the input terminal 2 and the output terminal 4. IC chip 7 electrically connected.

  Further, as shown in FIG. 2, the circuit module 1 of the present embodiment is a test that is electrically connected to the output terminal 4 on the surface of the circuit module 1 opposite to the surface on which the IC chip 7 of FIG. 1 is mounted. A pad 8 is provided. As shown in FIG. 3, the test pads 8 are staggered in the area on the back surface of the circuit module 1 opposite to the output terminal portion 5 of the circuit module 1, and the output terminals 4 provided on the output terminal portion 5 It is configured to be electrically connected through the blind via 9.

  As shown in FIG. 4, the circuit module 1 includes an insulating layer 10 made of a polyimide film, and conductor layers 11a and 11b made of copper foil and forming a wiring pattern on both surfaces of the insulating layer 10. In addition, an IC chip 7 that is pressure-bonded onto the ACF 12 that is affixed to the conductor layer 11a is mounted at a substantially central portion of the circuit module 1.

  As shown in FIG. 5, at the end of the wiring pattern made of the conductor layer 11a, an input terminal 2 and an output each having a nickel plating layer 13 subjected to nickel plating and a gold plating layer 14 subjected to gold plating. Terminal 4 is formed. Further, a cover resist layer 15a coated with a solder resist is formed as a protective cover for preventing a short circuit or disconnection of the wiring on a portion other than the wiring pattern on which the input terminal 2 and the output terminal 4 are formed. .

  As shown in FIG. 4, a reinforcing plate 17 made of a polyethylene terephthalate film adhered to the insulating layer 10 with an adhesive material 16 is provided on the back surface of the input terminal portion 3 on which the input terminals 2 are arranged. In the present embodiment, as shown in FIG. 2, a test pad 18 that is electrically connected to the input terminal 2 is also provided on the back surface of the input terminal portion 3.

  As shown in FIGS. 3 and 5, a wiring pattern of a conductive layer 11 b that is electrically connected to the output terminal 4 through the blind via 9 is formed on the back surface of the output terminal portion 5 in which the output terminal 4 is arranged. A test pad 8 is formed at the end of the wiring pattern. A cover resist layer 15b is also formed on portions other than the test pad 8 other than the wiring pattern.

  The blind via 9 electrically connects the conductor layer 11a and the conductor layer 11b, which are wiring patterns of copper foil formed on both surfaces thereof, via the insulating layer 10 made of polyimide film by the copper plating layer 19.

  As shown in FIG. 3, the test pads 8 provided in the region on the back surface of the output terminal portion 5 are arranged in a staggered manner. Therefore, when the test pads 8 are regularly arranged, the inspection probes contacting the test pads 8 are regularly arranged, and the distance between adjacent test pads is set to a value larger than the arrangement pitch of the output terminals. Can do. Thereby, an inspection device that is relatively easy to design can be used.

  Next, an electrical inspection for inspecting a malfunction of the IC chip 7 mounted on the circuit module 1 of the present embodiment will be described.

  The circuit module 1 of this embodiment includes a test pad 8 that is electrically connected to the output terminal 4 on the back surface of the output terminal portion 5 on the mounting surface side. Therefore, before or after crimping the electrodes of the liquid crystal panel substrate and the output terminals 4 of the circuit module 1, they are connected to a circuit between the output terminals 4 connected to the electrodes of the liquid crystal panel substrate and the IC chip 7. The test pad 8 acquires a signal output from the IC chip 7 with respect to the signal input to the input terminal 2.

  Next, using the signal acquired through the test pad 8, an electrical test is performed to determine whether the IC chip 7 operates normally.

  And before crimping, as a result of electrical inspection, the yield of the liquid crystal panel on which the circuit module 1 is mounted is improved by mounting the circuit module 1 on which the IC chip 7 operates normally on the liquid crystal panel.

  Further, in the case after crimping, as a result of electrical inspection, a liquid crystal module in which a backlight or the like is incorporated is formed only on the liquid crystal panel on which the circuit module 1 in which the IC chip 7 operates normally is mounted. The yield of the liquid crystal module is improved.

DESCRIPTION OF SYMBOLS 1 ... Circuit module, 2 ... Input terminal, 3 ... Input terminal part, 4 ... Output terminal, 5 ... Output terminal part, 6 ... Flexible printed circuit board, 7 ... IC chip, 8 ... Test pad, 9 ... Blind via, 10 ... Insulating layer, 11a, 11b ... conductor layer, 12 ... ACF.

Claims (3)

A flexible printed circuit board having a crimping region and an input terminal in which an output terminal to be crimped to an electrode of the liquid crystal panel substrate is provided;
Mounted on the surface of the flexible printed circuit board on the side of the crimping region, and comprising an IC chip electrically connected to the input terminal and the output terminal,
A circuit module comprising a test pad electrically connected to the output terminal on a surface opposite to a surface on which the IC chip is mounted. The circuit module according to claim 1,
The circuit module according to claim 1, wherein the test pads are arranged in a staggered manner in a region on a surface opposite to the crimping region. The circuit module according to claim 1 or 2,
A circuit module comprising a blind via for electrically connecting the output terminal and the test pad.

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