Processing methods

Abstract

To provide a processing method that makes it possible to perform desired processing on a wiring board without contaminating the wiring board and device chips.SOLUTION: The processing method for processing a wiring board on which device chips are provided on the front and back surfaces includes a sealing step, a fixing step, and a processing step. The sealing step is for sealing the wiring board with a thermo-compression bonding sheet by wrapping the wiring board with the thermo-compression bonding sheet, heating the wiring board, and removing air from the wiring board. The fixing step is for fixing the front and back surface sides of the wiring board sealed with the thermo-compression bonding sheet to a substrate. The processing step is for holding the substrate on a chuck table of a processing device and performing desired processing on the wiring board by means of processing means constituting the processing device.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for processing a wiring board having device chips disposed on its front and back surfaces. [Background technology]

[0002] A wafer having a plurality of devices such as ICs and LSIs formed on its surface defined by division lines is separated into individual device chips by a dicing machine or a laser processing machine. The chips are then mounted on wiring boards and used in electrical devices such as mobile phones and personal computers.

[0003] Generally, a wiring board is formed into a predetermined shape corresponding to the form of an electric device such as a mobile phone or a personal computer, and is assembled into the electric device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-163634 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when device chips are disposed on the front and back surfaces of a wiring board, when the front and back surfaces of the wiring board are inverted in order to process the front and back surfaces of the wiring board, support portions for supporting the wiring board may be formed on the wiring board. This poses a problem that processing must be performed to remove such unnecessary portions without contaminating the wiring board and device chips before assembly into the electrical equipment, resulting in an unbearable burden.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its main technical object is to provide a processing method capable of performing desired processing on a wiring board without contaminating the wiring board and device chips. [Means for solving the problem]

[0007] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a processing method for a wiring board having device chips disposed on its front and back surfaces, comprising a sealing step of wrapping the wiring board in a thermocompression sheet, heating it, removing air, and sealing the wiring board with the thermocompression sheet, a substrate fixing step of fixing the front side or the back side of the wiring board sealed with the thermocompression sheet to a substrate, and a processing step of holding the substrate on a chuck table of a processing device and performing a desired processing on the wiring board by a processing means constituting the processing device.

[0008] The processing means is preferably a cutting means having a rotatable cutting blade having a cutting edge on its outer periphery, and is adapted to cut off unnecessary portions of the wiring board. Effect of the Invention

[0009] The processing method of the present invention is a method for processing a wiring board having device chips on the front and back sides, and includes a sealing step of wrapping the wiring board in a thermocompression sheet, heating it, removing air, and sealing the wiring board with the thermocompression sheet, a substrate fixing step of fixing the front side or back side of the wiring board sealed with the thermocompression sheet to a substrate, and a processing step of holding the substrate on a chuck table of a processing device and performing a desired processing on the wiring board by a processing means constituting the processing device, so that the wiring board can be processed as desired without contaminating the wiring board and the device chips, and for example, unnecessary parts can be removed from the wiring board. Therefore, the problem of the troublesome work of performing a desired processing without contaminating the wiring board and the device chips before assembling the wiring board in a predetermined electric device is solved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a wiring board processed by a processing method according to an embodiment of the present invention; [Diagram 2] 2 is a perspective view showing a state in which the wiring board shown in FIG. 1 is wrapped with a thermocompression sheet. FIG. [Diagram 3] 3 is a perspective view showing a mode in which the outer peripheral region of the thermocompression-bonding sheet shown in FIG. 2 is thermocompression-bonded. FIG. [Figure 4] 4 is a perspective view showing a mode in which the central region of the thermocompression sheet shown in FIG. 3 is thermocompression-bonded. FIG. [Diagram 5] 5 is a perspective view showing a manner in which an excess area of ​​the thermocompression sheet shown in FIG. 4 is separated. FIG. [Figure 6] 1 is a perspective view showing an embodiment of a substrate fixing step for fixing a wiring board to a substrate; [Figure 7] FIG. 2A is a perspective view showing an embodiment of a processing step for performing a desired processing on a wiring board, and FIG. 2B is a perspective view of the wiring board after the processing method is completed and the thermocompression sheet has been peeled off. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a processing method configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0012] FIG. 1 shows a perspective view of a wiring board 10 processed by the processing method of the present embodiment. A plurality of device chips 11, 12, 13, and 14 are arranged on the front surface 10a side of the wiring board 10. Although not shown, a plurality of device chips are also arranged on the back surface 10b side of the wiring board 10. As shown in FIG. 1, the wiring board 10 is a substantially rectangular board, and support pieces 15 and 16 that are held when forming a device on the wiring board 10 are formed on the opposing short sides 10c and 10d. The support pieces 15 and 16 are unnecessary parts when the wiring board 10 is assembled into a predetermined electric device, and are parts that are processed and cut by the processing method implemented by the present embodiment. In the present embodiment, the support pieces 15 and 16 are formed only on the short sides 10c and 10d, but they may be formed on the opposing long sides 10e and 10f.

[0013] The processing method of this embodiment, which is carried out to prepare the wiring board 10 having the device chips disposed on the front surface 10a and the back surface 10b so as to be in a state in which the wiring board 10 can be assembled into a predetermined electric device, will be described below.

[0014] When carrying out the processing method of this embodiment, once the unprocessed wiring substrate 10 described above is prepared, the sealing step described below is carried out.

[0015] When carrying out the sealing step, as shown in the upper part of Fig. 2, thermocompression sheets 22, 24 having a size capable of wrapping the wiring board 10 are prepared. The thermocompression sheets 22, 24 are sheets that are not coated with a glue or the like on the surface and exhibit adhesive strength when heated, and are preferably selected from polyolefin-based sheets or polyester-based sheets. When selecting from polyolefin-based sheets, it is preferable to select from, for example, polyethylene sheets, polypropylene sheets, and polystyrene sheets, and when selecting from polyester-based sheets, it is preferable to select from, for example, polyethylene terephthalate sheets and polyethylene naphthalate sheets. The temperature at which the thermocompression sheets 22, 24 are heated varies depending on the material of the sheet, and by heating to a temperature close to the melting temperature of each sheet, adhesive strength can be exhibited more effectively.

[0016] In this embodiment, a case will be described where polyethylene sheets are selected as the thermocompression sheets 22, 24. As can be seen from the figure, the thermocompression sheets 22, 24 are selected in a size that can wrap the entire wiring board 10 including the support pieces 15, 16 and ensure an excess area on the periphery for bonding the thermocompression sheets 22, 24 together with pressure. Note that the thermocompression sheets of the present invention are not limited to two sheets, and may be, for example, a single thermocompression sheet having an area capable of wrapping the front surface 10a and the back surface 10b of the wiring board 10, which is folded and used.

[0017] Once the above-mentioned thermocompression sheets 22, 24 have been prepared, as shown in the figure, the back surface 10b of the wiring board 10 is placed in the center of one of the thermocompression sheets 24, and the other thermocompression sheet 22 is placed over the front surface 10a of the wiring board 10, so that the entire wiring board 10 is wrapped in the thermocompression sheets 22, 24, as shown in the lower part of Figure 2.

[0018] Next, a heating roller 30 shown in FIG. 3 is prepared as a means for performing thermocompression bonding. The heating roller 30 is provided with a heating means (not shown) for heating the surface 32 of the heating roller 30 therein, which is a means for heating to a predetermined temperature, for example, 120°C to 140°C, at which the thermocompression sheets 22, 24 exert their adhesive force. The surface 32 is also coated with a fluororesin so that the thermocompression sheets 22, 24 do not adhere to the heating roller 30 even if the thermocompression sheets 22, 24 exert their adhesive force due to the heating. Once the heating roller 30 is prepared, the heating roller 30 is heated to the predetermined temperature and rotated in the direction indicated by the arrow, and the thermocompression sheets 22, 24 are pressed against the outer peripheral region 26 surrounding the wiring board 10, thereby thermocompression bonding the thermocompression sheets 22 and 24 together. At this time, as shown in FIG. 3, the heat roller 30 does not perform thermocompression bonding on the central region 27 where the wiring board 10 is placed and on the suction region 28 which is a part of the outer circumferential region 26.

[0019] Next, as shown in the upper part of FIG. 4, a suction pump (not shown) is connected to the suction port 28a of the suction region 28, and a negative pressure V is generated at the suction port 28a to remove air from the central region 27 that encases the wiring board 10. At the same time, hot air H is supplied from above the thermocompression sheet 22 and below the thermocompression sheet 24 to heat the thermocompression sheets 22, 24 to the above-mentioned predetermined temperature (120°C to 140°C). As a result, the thermocompression sheets 22, 24 are thermocompressed in close contact with the front surface 10a and back surface 10b of the wiring board 10 in the central region 27 that encases the wiring board 10 without any gaps. At the same time that the thermocompression of the central region 27 is completed, the air intake port 28a is closed and the suction region 28 is also thermocompressed. As a result, the wiring board 10 is sealed and integrated by the thermocompression sheets 22, 24, the device chips formed on the front surface 10a and back surface 10b of the wiring board 10 are lifted up, and the sealing process of this embodiment is completed as shown in the lower part of Figure 4.

[0020] The specific form of thermocompression bonding of the thermocompression sheets 22, 24 in carrying out the sealing step is not limited to the above embodiment. For example, instead of the heating roller 30, a flat heating and pressing means corresponding to the outer peripheral region 26 surrounding the wiring board 10 may be prepared, and the heating and pressing means may be pressed against the outer peripheral excess region 26 to perform thermocompression bonding. The heating method using the hot air H is also not limited to this, and the thermocompression sheets 22, 24 may be heated by irradiating them with infrared rays, for example.

[0021] After the above-mentioned sealing step is performed to form the wiring board 10 sealed by the thermocompression sheets 22 and 24, the substrate fixing step described below is performed. In this embodiment, the surplus area separation step described below is performed before the substrate fixing step is performed. The surplus area separation step is performed to obtain a shape more suitable for performing the substrate fixing step described below, and can be omitted as appropriate depending on the size of the wiring board 10, the size of the thermocompression sheets 22 and 24, etc.

[0022] In the excess region separation step, as shown in Fig. 5, the wiring board 10 sealed and integrated by the thermocompression sheets 22, 24 is placed on the upper surface Ta of an appropriate table T, and a separation groove 100 is formed along the outer periphery of the wiring board 10 by an appropriate separation means 40 to remove the excess region 29, and the wiring board 10 is shaped into a rectangular shape smaller than the thermocompression sheets 22, 24 before separation as shown in the lower part of Fig. 5. Even in the rectangular shape from which the excess region 29 has been removed, the wiring board 10 is entirely wrapped by the thermocompression sheets 22, 24 from which the excess region 29 has been removed, and the integrated state by thermocompression is maintained.

[0023] After the above-mentioned excess region separation step is performed, a substrate 50 shown in FIG. 6 is prepared. The substrate 50 is, for example, a circular plate-like member having rigidity, and is made of glass, stainless steel, or the like. When the wiring board 10 sealed by the thermocompression sheets 22, 24 is fixed to the substrate 50, for example, liquid resin P is first dripped onto the center of the substrate 50. After the liquid resin P is dripped, the wiring board 10 sealed by the thermocompression sheets 22, 24 is placed on the substrate 50 with either the front surface 10a or the back surface 10b facing upward. In this embodiment, the wiring board 10 is placed on the liquid resin P with the front surface 10a facing upward and the back surface 10b facing downward. The liquid resin P hardens over time, and the wiring board 10 is fixed onto the substrate 50 as shown in the lower part of FIG. 6, completing the substrate fixing step of this embodiment. The liquid resin P is interposed between the substrate 50 and the wiring board 10, and thus unevenness caused by the device chips on the rear surface 10b of the wiring board 10 is absorbed, and the wiring board 10 is stably fixed onto the substrate 50. In the above-described embodiment, the liquid resin P is used to fix the wiring board 10 sealed by the thermocompression sheets 22, 24 to the substrate 50, but the liquid resin P is not particularly limited as long as it is a material capable of absorbing unevenness caused by the device chips arranged on the wiring board 10 and performing the function of fixing the wiring board 10 to the substrate 50. For example, wax that melts when heated and solidifies when cooled, or a flexible double-sided tape can be used.

[0024] After the substrate fixing step described above is performed, the substrate 50 to which the wiring board 10 is fixed is transferred to a cutting device 60 (only a part of which is shown) which is a processing device of this embodiment shown in FIG. 7(a), and the substrate 50 to which the wiring board 10 is fixed is held on a holding surface 62a of a chuck table 62. Next, a cutting means 63 which is provided with a rotatable cutting blade 64 having a cutting edge on the outer periphery and which is arranged as a processing means of the cutting device 60 and cuts off an unnecessary portion of the wiring board is positioned on a straight line along the short side 10c of the wiring board 10. Next, the cutting blade 64 is rotated and cuts downward while being processed and fed along the short side 10c, cutting off the support piece 15 which is an unnecessary portion when the wiring board 10 is assembled to a predetermined electric device. Following this, a similar cutting process is performed to cut off the support piece 16 which is also an unnecessary portion from the wiring board 10 along the short side 10d, completing the processing step of this embodiment and the processing method of this embodiment.

[0025] After carrying out the above-mentioned processing steps, the thermocompression sheets 22, 24 remaining on the front surface 10a and back surface 10b of the wiring board 10 can be peeled off at any time before the wiring board 10 is assembled into a predetermined electric device, to obtain the state shown in Fig. 7(b). When performing the peeling, the thermocompression sheets 22, 24 are cooled or heated to make them easy to peel off. As described above, no adhesive or the like is applied to the thermocompression sheets 22, 24, and even if the thermocompression sheets 22, 24 are peeled off, no adhesive or the like is left adhering to the wiring board 10, and no deterioration in quality is caused.

[0026] According to the processing method of the embodiment described above, the wiring board 10 and the device chips formed on the front surface 10a and the back surface 10b of the wiring board 10 are protected by the thermocompression sheets 22, 24, and the wiring board 10 sealed and integrated by the thermocompression sheets 22, 24 is firmly fixed to the substrate 50 and put into a state where it is easy to process, so that it is possible to remove unnecessary parts (the support pieces 15, 16 in the embodiment described above) from the wiring board 10 by processing with the cutting device 60 without contaminating the wiring board 10 and the device chips with processing debris, etc. Therefore, the problem that the work of performing the desired processing on the wiring board 10 is unbearable without contaminating the wiring board 10 and the device chips before assembling the wiring board 10 to a predetermined electric device is solved.

[0027] In the above embodiment, an example has been shown in which the processing step is performed by cutting processing to remove unnecessary portions of the wiring board 10 using the cutting device 60 equipped with the cutting blade 64, but the present invention is not limited to this. For example, the processing step performed by the present invention may be laser processing in which a laser beam is irradiated by a laser processing device to remove unnecessary portions of the wiring board 10.

[0028] Furthermore, the desired processing performed by the processing step of the present invention is not limited to the above-mentioned processing of removing the support pieces 15, 16, but may be, for example, a drilling process for forming holes in the wiring board 10. Even when such a drilling process is performed, the above-mentioned sealing process and substrate fixing process are performed, so that the wiring board 10 and the device chips are not contaminated and the problem of the work being unbearable when performing the desired processing on the wiring board 10 is solved. [Explanation of symbols]

[0029] 10: Wiring board 10a: surface 10b: Back side 10c, 10d: Short side 10e, 10f: Long side 11~14: Device chip 15, 16: Support piece 22, 24: Heat-sealed sheet 26: Outer area 27: Central area 28: Suction area 28a: Suction port 30: Heating roller 32: Surface 40: Separation means 50: Substrate 60: Cutting equipment 62: Chuck table 62a: Holding surface 64: Cutting blade 100: Cutting groove P:Liquid resin

Claims

1. A method for processing a wiring substrate having device chips disposed on a front surface and a back surface, comprising the steps of: a sealing process in which the wiring board is wrapped in a thermocompression sheet, heated, and air is removed, and the wiring board is sealed with the thermocompression sheet; a substrate fixing step of fixing the front side or the back side of the wiring board sealed with the thermocompression sheet to a substrate; a processing step of holding the substrate on a chuck table of a processing device and subjecting the wiring board to a desired processing by a processing means constituting the processing device; A processing method comprising the steps of:

2. 2. The processing method according to claim 1, wherein the processing means is a cutting means provided with a rotatable cutting blade having a cutting edge on its outer periphery, and cuts off unnecessary portions of the wiring board.

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