An electronic module according to the present invention includes a first electronic parts having a first electrode terminal, a second electronic parts having a second electrode terminal, and a conductive connection material formed between the first electrode terminal and the second electrode terminal, for electrically connecting the first electrode terminal with the second electrode terminal. The second electrode terminal includes plural branch portions located in a portion other than a portion which is in contact with the conductive connection material. The electronic module further includes a third electronic parts having a third electrode terminal. At least one of the plural branch portions of the second electrode terminal is electrically connected with the third electrode terminal.
The second electrode terminal includes the plural branch portions located in the portion other than the portion which is in contact with the conductive connection material, so a connection resistance of the conductive connection material for connecting the first electronic parts with the second electronic parts can be measured. When the branched portions (branch portions) of the second electronic parts are electrically connected with the third electrode terminal of the third electronic parts, the second electrode terminal including the branch portions can be used as an actual wiring.
Hereinafter, an exemplary embodiment for embodying the present invention will be described with reference to the attached drawings.
As illustrated in
As illustrated in
Then, two probes (wire resistance measurement) P are brought into contact with the electrode wiring 1 of the board 1 serving as the first electronic parts. Two wirings are led from the branch portion ends 8 through the two branch potions 6 of the FPC 4. The two probes P and the two wirings are connected with a multimeter M for four-wire resistance measurement to measure a low resistance value of an ACF bonding portion.
A structure of the FPC 4 will be more specifically described. The FPC 4 includes the ACF bonding wirings 5 to be connected by thermocompression bonding, the branch portions 6, and a translucent film for holding the ACF bonding wirings 5 and the branch portions 6. The ACF bonding wirings 5 to be formed have the pitch equal to the pitch of the electrode wirings 2 of the board 1 which are located on an opposite side and the wiring width substantially equal to the wiring width thereof. The branch portions 6 are obtained by dividing each of the ACF bonding wirings 5 into substantially two. Each of the branch portions 6 have a wiring width equal to ½ of the wiring width of the ACF bonding wiring 5. A gap of approximately 20 μm is formed between the branch portions.
The wiring width of each of the branch portions 6 is not limited to ½ of the wiring width of the ACF bonding wiring 5 and thus may be ½ or less thereof or may be ½ or more thereof. At least two branch portions 6 are formed.
A sum of the wiring widths of the two branch portions 6 is desirably equal to or larger than the wiring width of the ACF bonding wiring 5 in the case where the branch portions 6 are used for a wiring for supplying a large current. When a supplied current is small or when the branch portions 6 are used for a signal line, the sum of the wiring widths of the branch portions 6 may be smaller than the wiring width of the ACF bonding wiring 5. One of the two branch portions 6 may be a thick wiring and the other thereof may be a thin wiring. When one of the wirings is used for only resistance measurement, the thin wiring can be used as a wiring for resistance measurement and the thick wiring can be used as a wiring for both resistance measurement and driving.
The gap formed between the branch portions may be any gap in which adjacent branch portions are not short-circuited. When the branch portions are provided as two wirings for four-wire resistance measurement using a four-wire resistance measurement instrument, the branch portions may be formed in any shape. When the two wirings can be led, two or more branch portions may be formed.
Then, the branch portion ends 8 of the FPC 4 serving as the second electronic parts are connected with a third electronic parts C as illustrated in
When the third electronic parts is an electronic parts connected with the second electronic parts, the third electronic parts is not particularly limited. However, for example, as illustrated in
In this embodiment, description has been made referring to an example in which both the two branch portion ends 8 of the second electronic parts are connected with the third electrode terminal. However, according to the present invention, all the plural branch portion ends may not necessarily be connected with the third electrode terminal. For example, as illustrated in
In this embodiment, the FPC is used as the second electronic parts. However, the present invention is not limited to the FPC. Therefore, any board having wirings connected with the electronic board serving as the first electronic parts, such as wirings for TAB or wirings formed on a glass epoxy thin board, may be employed.
In this embodiment, the electronic board in which only one group including the plural electrode wirings is provided on one side of the board is described. However, the electrode wirings may be formed on each of four sides of the board or plural groups each including electrode wirings may be provided on one side thereof. Although the electronic board including the plural electrode wirings is described, a single electrode wiring may be used.
When there is no problem in using the electronic board serving as the first electronic parts, as illustrated in
Examples of the electronic module include an FPC connected with a semiconductor integrated circuit board serving as the electronic board and an FPC connected with a display panel serving as the electronic board. Examples of an electronic devices containing the electronic module includes a camera, a printer, a facsimile machine, a medical device, a videocassette recorder, a DVD drive, a CD drive, an electronic calculator, various types of displays, and various types of measuring instruments. Examples of the displays include a liquid crystal display (LCD), an organic EL display (OELD), a plasma display panel (PDP), and a field emission display (FED), which are used for a display section of each of a television receiver, a personal computer, a mobile telephone, and a personal digital assistant (PDA). In particular, when an organic EL display operated by current driving is manufactured, light emission is significantly influenced by a resistance of the ACF connection portion. Therefore, an effect that a light emission intensity is made uniform is large in the case where the structure of the electronic module according to the present invention is employed. When the organic EL display is manufactured, the first electronic parts in this embodiment serves as an organic EL panel (organic electroluminescence panel).
Hereinafter, the electronic module according to the present invention and a method of manufacturing the electronic module will be described in a manufacturing order. However, the present invention is not limited to the following structures and the following manufacturing methods.
Hereinafter, the method of manufacturing the electronic module will be described.
(Condition Determination and Reliability Evaluation)
A heater head temperature, a compression bonding pressure, and a compression bonding time, each of which were an ACF connection condition, were changed. The first electronic parts was connected with the second electronic parts in each changed condition. Probes were brought into contact with portions immediately above the FPC, of an electrode wiring of the board of each electronic module which was bonded to the FPC. Two wirings were led from the branch portions of the FPC. The two probes and the two wirings were connected with the multimeter for four-wire resistance measurement to measure a low resistance value of the ACF connection portion. Such operation was performed for each of the electrode wirings in each condition to measure an initial resistance value.
The first electronic parts and the second electronic parts which were connected with each other in each changed condition were placed in a contrast temperature bath and a reliability test was performed under the condition of a high temperature and a high humidity for 1,000 hours. After a lapse of 1,000 hours, the first electronic parts and the second electronic parts which were connected with each other and placed in the bath were taken out. Then, as in the initial case, the two wirings were led from the branch portions of the FPC. The two probes and the two wirings were connected with the multimeter for four-wire resistance measurement to measure a low resistance value of only the ACF connection portion. Such measurement was performed in each condition.
Members having highest reliability were determined based on the initial resistance values and a result obtained by measurement on a change in resistance value during 1,000 hours. A heater head temperature, a compression bonding pressure, and a compression bonding time with respect to the determined members were set as manufacturing conditions.
In this example, the test is performed at a high temperature and a high humidity for 1,000 hours. However, a heat cycle test which can be carried out in a relatively short time may be performed as the reliability test to determine the conditions.
(Connection between First Electronic Parts and Second Electronic Parts)
The first electronic parts in which the electrode wirings (first electrode terminals) were formed on the board and the second electronic parts in which the ACF bonding wirings (second electrode terminals) had been formed were prepared. The ACF connection was made based on the manufacturing conditions obtained by the condition determination to connect the first electronic parts with the second electronic parts.
The ACF 9 having a length required for the electrode wirings 2 of the board 1 was temporarily bonded by compression thereto. Then, the board alignment marks 3 of the board 1 were aligned with the FPC alignment marks 7 of the FPC 4. After the mark position alignment, the board 1 and the FPC 4 were set below a thermocompression bonding head (not shown) and bonded to each other by compression through the ACF 9 with the manufacturing conditions including the heater head temperature, the compression bonding pressure, and the compression bonding time, with the result that the first electronic parts was connected with the second electronic parts.
(Check of ACF Connection Portion)
One of groups each including the first electronic parts and the second electronic parts which had been compression-bonded by the above-mentioned process was extracted and the two probes P were brought into contact with portions immediately above the FPC 4 of the electrode wiring 2 of the board 1 which was bonded to the FPC 4. The two wirings were led from the branch portion ends 8 of the branch portions 6 of the FPC 4. The two probes and the two wirings were connected with the multimeter M for four-wire resistance measurement to measure a low resistance value of only the ACF connection portion. A resistance value of each of the electrode wirings of the electronic module was measured in the same manner. In such measurement, when a specific four-wire resistance measurement jig is used instead of the probes, the resistance can be more easily measured in a short time.
For comparison, the conventional first electronic parts and the second electronic parts as illustrated in
For each group including the first electronic parts and the second electronic parts which were connected with each other, the two probes were brought into contact with the portions immediately above the FPC, of the electrode wiring of the board which was bonded to the FPC. The two wirings were led from end terminals of the FPC. The two probes and the two wirings were connected with the multimeter for four-wire resistance measurement to perform resistance value measurement. A resistance value of each of the electrode wirings of each member was measured.
(Measurement Value Comparison)
An average value of resistance measurement values in the case of Example 1 was 0.37Ω. An average value of resistance measurement values in the comparison example was 4.5Ω. Therefore, there was a large difference in the resistance values. This reason is as follows. In the conventional case, a large resistance value is exhibited because a resistance value of the entire electronic parts is also included thereto. On the other hand, in the case of Example 1, the resistance value of only the ACF connection portion can be substantially measured.
As described above, in the conventional case, the resistance value of the connection portion was hidden in the large resistance value of the entire electronic parts, so it was difficult to detect a fault in the connection portion. In contrast, when the low resistance value can be measured as in the case of Example 1, whether or not the manufacturing conditions of the electronic module have abnormality or whether or not partial fault occurs can be instantaneously determined by a sampling inspection. Therefore, accurate inspection and evaluation can be performed.
In this example, the sampling inspection of manufacturing lots was performed. However, a 100% inspection may be performed instead of the sampling inspection.
The condition determination and the reliability test can be performed using products, so it is unnecessary to manufacture specific electronic parts for condition determination and reliability test and a manufacturing cost is reduced.
(Connection between Second Electronic Parts and Third Electronic Parts)
The third electronic parts in which the third electrode terminals had been formed was prepared. The third electronic parts was connected with the first electronic parts and the second electronic parts which had been connected with each other through the ACF. In this example, the ACF connection was performed as in the case of the connection between the first electronic parts and the second electronic parts. The ACF having a length required for the third electrode terminals 31 of the controller 32 was temporarily bonded by compression thereto. Then, board alignment marks of the controller 32 were aligned with the FPC alignment marks of the FPC 4. After the mark position alignment, the controller 32 and the FPC 4 were set below the thermocompression bonding head (not shown) and bonded to each other by compression through the ACF with the manufacturing conditions including the heater head temperature, the compression bonding pressure, and the compression bonding time, with the result that the electronic module is produced.
A point in which this electronic module is different from the electronic module according to Example 1 will be described.
(Condition Determination and Reliability Evaluation)
As in the case of Example 1, in order to determine the manufacturing conditions, the first electronic parts was connected with the second electronic parts. As illustrated in
As a result obtained by measurement after the test, a heater head temperature, a compression bonding pressure, and a compression bonding time with respect to members having highest reliability were set as the manufacturing conditions.
(Connection Between First Electronic Parts and Second Electronic Parts)
An ACF (not shown) having a length required for the electrode wirings 12 of the board 11 was temporarily bonded by compression thereto. Then, board alignment marks (not shown) of the board 11 were aligned with FPC alignment marks (not shown) of the FPC 14. After the mark position alignment, the board 11 and the FPC 14 were set below the thermocompression bonding head (not shown) and bonded to each other by compression through the ACF with the manufacturing conditions including the heater head temperature, the compression bonding pressure, and the compression bonding time, with the result that the first electronic parts was connected with the second electronic parts.
(Check of ACF Connection Portion)
One of groups each including the first electronic parts and the second electronic parts which had been compression-bonded by the above-mentioned process was extracted and the two probes P were brought into contact with portions immediately above the FPC 14, of the electrode wiring 12 of the board 11 which was bonded to the FPC 14. Two wirings were led from the lower electrode 16 and the upper electrode 18 which were the two-layer wirings of the FPC 14. The two probes P and the two wirings were connected with the multimeter M for four-wire resistance measurement to measure a low resistance value of only the ACF connection portion. A resistance value of each of the electrode wirings of the electronic module was measured by the above-mentioned operation. As a result, it could be determined that there was no problem on the bonding states of all the wirings. In such four-wire resistance measurement, when a specific four-wire resistance measurement jig is produced instead of the probes, the resistance can be more easily measured in a short time.
The FPC 14 includes the ACF bonding wirings 15 to be connected by thermocompression bonding, the lower electrodes 16, the upper electrodes 18, and a film for holding the ACF bonding wirings 5, the lower electrodes 16, and the upper electrodes 18. The upper electrodes 18 to be formed have a pitch equal to a pitch of the electrode wirings 12 of the board 11 which are located on an opposite side and a wiring width substantially equal to a wiring width thereof. The lower electrodes 16 serving as lower branch wirings have a pitch equal to a pitch of the ACF bonding wirings 15 and a width substantially equal to a width thereof. A current may be led from one of the lower electrode 16 and the upper electrode 18. In the case of a wiring for supplying a large current, the current may be supplied from two upper and lower wirings.
When a supplied current is small or when the lower electrode 16 and the upper electrode 18 are used for a signal line, the width of each thereof may be smaller than the width of the ACF bonding wiring 15. One of the lower electrode 16 and the upper electrode 18 which are lower and upper wirings may be a thick wiring and the other thereof may be a thin wiring. When two wirings are led for four-wire resistance measurement, branch portions each including two or more wiring layers may be formed.
In this example, the sampling inspection of manufacturing lots was performed. However, a 100% inspection may be performed instead of the sampling inspection.
The condition determination and the reliability test can be performed using products, so it is unnecessary to manufacture specific electronic parts for condition determination and reliability test and a manufacturing cost is reduced.
In this example, the wirings can be led from the same positions in a longitudinal direction of the terminal portion. Therefore, for example, the contact with a connector can be made at any of the positions. The contact can be made with each of the upper and lower wirings, so two kinds of connectors can be used. Even in the case of the ACF connection, the bonding can be made with any of the upper and lower wirings, so a leading manner which is more suitable for the electronic module can be employed.
(Connection Between Second Electronic Parts and Third Electronic Parts)
The third electronic parts was further connected with the first electronic parts and the second electronic parts which had been connected with each other through the ACF. In this example, the ACF connection was performed as in the case of the connection between the first electronic parts and the second electronic parts. The ACF having a length required for the third electrode terminals of the controller was temporarily bonded by compression thereto. Then, the board alignment marks of the controller were aligned with the FPC alignment marks of the FPC. After the mark position alignment, the controller and the FPC were set below the thermocompression bonding head (not shown) and bonded to each other by compression through the ACF with the manufacturing conditions including the heater head temperature, the compression bonding pressure, and the compression bonding time, with the result that the electronic module was produced.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Applications No. 2006-228754, filed Aug. 25, 2006, and 2007-202724, filed Aug. 3, 2007, which are hereby incorporated by reference herein in their entirety.
Number | Date | Country | Kind |
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2006-228754 | Aug 2006 | JP | national |
2007-202724 | Aug 2007 | JP | national |