Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders or supports
  • H03H9/10—Mounting in enclosures
  • H03H9/1064—Mounting in enclosures for surface acoustic wave [SAW] devices
  • H03H9/1085—Mounting in enclosures for surface acoustic wave [SAW] devices the enclosure being defined by a non-uniform sealing mass covering the non-active sides of the SAW device
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
  • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
  • H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
• • H10W72/90—
• • H10W72/923—
• • H10W72/9415—
• • H10W90/724—
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/42—Piezoelectric device making

Definitions

• the present invention relates to a surface acoustic wave device, and more particularly to a surface acoustic wave device with a reduced package size and a method of manufacturing the same.
• FIG. 10 shows the structure of the CSP type SAW device of the prior art 1 described above, in which an IDT and an electrode for exciting the SAW are excited on the lower main surface 103 a of the piezoelectric substrate in the figure. It has a SAW chip 103 on which pads are arranged and a mounting board 101 on which a connection pad 102 is arranged on the upper main surface 101 a in the figure.
• the electrode pad and the connection pad 102 provided on the mounting substrate 101 are conductively fixed via metal bumps 104, and the upper main surface 103b and side surface of the SAW chip 103 in the drawing are shown.
• the resin sheet so that it adheres This is a SAW device that is covered with a gate 105 and has an airtight space 106 formed between the surface 103a and the surface 101a.
• a resin sheet 105 is placed on the upper surface of the SAW chip 103 and heated to a resin softening temperature. Thereby, the resin sheet 105 is deformed so as to be in close contact with the surface contours of the SAW chip 103 and the mounting board 101. After the resin sheet 105 is deformed, the resin sheet 105 is further heated to give fluidity to the resin sheet 105 and is cured so that the resin sheet 105 is bonded to the SAW chip 103 and the mounting substrate 101, and the shape of the resin sheet 105 is changed. Fix it.
• the prior art 1 since the area of the upper surface of the SAW chip 103 is smaller than that of the mounting board 101, it is difficult to perform a masking identification for a filter or to perform suction for a device pickup.
• the structure is such that the resin sheet 105 having a small thickness is simply adhered along the outer surface of the SAW chip 103, there is a problem that the resin sheet 105 is easily damaged and the moisture resistance is weak.
• the resin sheet 105 is brought into close contact with the SAW chip 103 by generating a contraction force by applying a temperature gradient to the resin sheet 105, so that the resin sheet 105 becomes thinner at the corner A of the SAW chip 103, and the SAW chip 103 becomes thinner. It may be exposed to the outside, which may cause quality problems.
• FIG. 11 A jig 200 having a shape conforming to the outer shape of the chip 103 is provided, and the resin sheet 105 is brought into close contact with the inner wall 200a by sucking gas from the hole 201a of the suction tube 201 to change the shape. Then, the jig 200 is placed on the SAW chip 103, and the resin sheet 105 is heated so that the resin sheet 105 is in close contact with the surface of the mounting board 101 with the SAW chip 103.
• Prior Art 2 since the shape of the resin is changed in advance and then the resin is brought into close contact with the SAW chip, the possibility that the corners of the upper surface of the SAW chip are exposed to the outside is reduced. However, as in the prior art 1, the resin film is thin and thus easily damaged, and the problems such as low moisture resistance, and problems such as difficulty in marking and device pick-up work are not improved. . In addition, since resin sealing is performed using a jig, it is necessary to prepare a mold for each size of the SAW chip, so that there is a problem that work efficiency is poor.
• prior art 3 there is a structure disclosed in Japanese Patent Application No. 2002-334954 as another prior art (hereinafter referred to as prior art 3).
• Prior Art 3 the moisture resistance is improved because the conductive film layer is formed on the resin, but as in Prior Art 1 and 2, the resin sheet is thin, so it is easily damaged, and it is difficult to use for marking and device build-up. Problems such as difficulties in the work are not improved.
• the present invention has been made in order to solve the above-mentioned problems.
• a SAW device in which a SAW chip is flip-chip mounted on a mounting board and the surface is sealed with resin, the SAW chip is strongly protected and quality is improved. Improved SAW device It is intended to provide a manufacturing method. Disclosure of the invention
• the invention according to claim 1 of the present invention is directed to a method of flip-chip mounting a surface acoustic wave (SAW) chip on a mounting substrate and sealing the outer surface of the SAW chip with a resin.
• SAW surface acoustic wave
• the electrode pad provided on the lower surface of the SAW chip and the connection pad provided on the mounting substrate are electrically connected.
• L (X + Gx) (Y + Gy) (H + T + A) -XYT-XYA- ⁇ XVy A + Y Vx A + (4 Vx Vy A) / 3 ⁇ (L: one S AW type
• X the length of one side of the SAW chip
• Y the length of the other side of the SAW chip
• Gx the distance between adjacent SAW chips in the X direction
• Vx Distance from the dicing cut extending in the Y direction to the nearest side of the SAW chip.
• Gy Distance between adjacent SAW chips in the Y direction.
• Vy Distance from the dicing cut extending in the X direction to the nearest side of the SAW chip.
• the outer surface of one SAW chip is covered with a resin sheet.
• the resin sheet has a structure in which a protective film having releasability is attached to an upper surface of a resin sheet body having adhesiveness, and the lower surface of the resin sheet body is formed of the SAW.
• the said each process is performed in the state mounted on the chip
• the invention according to claim 3 is the method for manufacturing a SAW device according to claims 1 and 2, wherein the protective film is made of polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• the method for manufacturing a SAW device further comprising: The invention according to claim 6, wherein the laminating step includes the following steps: (1) After disposing the mounting substrate on which the SAW chip is mounted in a sealed container, the gas in the sealed container is discharged to reduce the pressure, Alternatively, after the step (2) and (1), the resin sheet is placed on the SAW chip and the resin sheet is softened. 4.
• the method for producing a SAW device further comprising: a step of pressing the resin sheet while melting the resin sheet.
• the invention according to claim 7 is characterized in that, in the laminating step, the atmosphere in the sealed container is replaced with an inert gas before the inside of the sealed container is depressurized or evacuated. 7.
• a method for manufacturing a SAW device according to any one of claims 1 to 6.
• the invention according to claim 9 is characterized in that, in the laminating step, the closed container has at least two spaces separated by a partition member, and the first space has the SAW chip mounted thereon and is provided on an upper surface of the SAW chip.
• a mounting board on which the resin sheet is mounted is disposed, and the atmosphere is maintained in a reduced pressure or vacuum state. The atmosphere in the second space is released to the atmospheric pressure, and the partition member is moved to the first space.
• the closed container in the laminating step, includes at least two spaces separated by a partition member, and the first space mounts the SAW chip and mounts the SAW chip on an upper surface of the SAW chip.
• a mounting substrate on which the resin sheet is mounted is arranged, and the atmosphere is maintained in a reduced pressure or vacuum state, and a pressure greater than the atmospheric pressure is applied to the atmosphere in the second space to cause the partition member to move to the first space.
• the SAW device manufacturing method according to any one of claims 1 to 8, wherein the resin sheet is pressed against the SAW chip by pressing against the space side.
• the invention according to claim 11 is the method for manufacturing a SAW device according to any one of claims 1 to 10, wherein in the laminating step, a surface of the partition member is an elastic body.
• An invention according to claim 12 is the method for manufacturing a SAW device according to any one of claims 1 to 11, wherein the press forming step is performed simultaneously with the laminating step.
• the invention according to claim 13 is the method for manufacturing a SAW device according to any one of claims 1 to 12, wherein the press molding step and the post-curing step are performed simultaneously with the laminating step.
• a laminating step is performed after arranging a flat plate having an area equal to or larger than the area where the SAW chip is mounted on the upper surface of the resin sheet.
• a frame is provided on the mounting board so as to overlap with a peripheral portion of the SAW chip, and the thickness of the frame is not less than 10 zm and not more than 30 m.
• the invention according to claim 18 is characterized in that, in the SAW chip, a dam is provided on an outer peripheral portion of the SAW chip except for a SAW excitation portion, and the thickness of the dam is 10 zm or more and 30 zm or less.
• Item 18 A method for manufacturing a SAW device according to any one of Items 1 to 16.
• the invention according to claim 19 wherein a dam is provided on an outer peripheral portion of the SAW chip except for an exciting portion of SAW, and a frame is provided on the mounting board at substantially the same position as the dam. 17.
• the invention according to claim 20 is the method for manufacturing a SAW device according to claims 17 to 19, wherein at least one of the frame and the dam is made of a photosensitive resin.
• the invention according to claim 22 is characterized in that the height of the connection pad formed on the mounting board is reduced by 10 to 30 zm with respect to a region of the mounting board other than the connection pad.
• the mounting board has a structure in which a plurality of individual mounting boards are connected and integrated, and includes a step of cutting into individual pieces. 23.
• FIG. 1 shows a flip chip mounting process of a SAW device according to the present invention.
• (A) is a plan view and
• (b) is a cross-sectional view.
• FIG. 2 is a view showing a step of placing a resin sheet of a SAW device according to the present invention on a SAW chip.
• FIG. 3 is a view showing a vacuuming step of the SAW device according to the present invention.
• FIG. 4 is a diagram showing a laminating step and a press forming step of the SAW device according to the present invention.
• FIG. 5 is a view showing a state after a post-curing step of the SAW device according to the present invention.
• FIG. 6 is a view showing a state after the dicing step of the SAW device according to the present invention.
• FIG. 7 (a) and 7 (b) are views showing another manufacturing procedure of the SAW device according to the present invention.
• FIGS. 8 (a) to 8 (c) are enlarged views of a mounting substrate preform at the time of laminating a SAW device according to the second embodiment of the present invention.
• FIGS. 9 (a) to 9 (d) are enlarged views of a mounting substrate preform at the time of laminating the SAW device according to the third embodiment of the present invention.
• FIG. 10 is a diagram showing the structure of a conventional SAW device.
• FIG. 11 is a diagram showing the structure of a second conventional SAW device. BEST MODE FOR CARRYING OUT THE INVENTION
• FIGS. 1 (a) and 1 (b) are a plan view and a cross-sectional view showing a process of flip-chip mounting the SAW chip 15 on a mounting board base material 40 having a structure in which the mounting board 2 is connected in a sheet shape. is there.
• the mounting board 2 has external electrodes 4 for surface mounting on the bottom of the insulating board 3 and electrical connection with the SAW chip 15 on the top. And an internal conductor 6 for conducting between the external electrode 4 and the connection pad 5 therein.
• the SAW chip 15 has an IDT 17 for exciting SAW on the main surface of the piezoelectric substrate 18 and a connection pad 16 electrically connected to the IDT 17. Then, flip-chip mounting is performed by connecting the connection pad 5 on the mounting board 2 and the connection pad 16 on the SAW chip 15 using the conductor bump 10.
• FIG. 2 shows a process of mounting the resin sheet 30 so as to straddle the upper surfaces of the plurality of SAW chips 15 mounted on the mounting substrate base material 40 of FIG.
• a protective film 32 having releasability is releasably attached to one surface of the resin sheet main body 31 having adhesiveness.
• PET polyethylene terephthalate
• the protective film is used for the protective film.
• tr is set under the following conditions.
• the resin sheet main body 31 As described above, by setting the thickness of the resin sheet main body 31, when the resin is later laminated on the SAW chip, the resin thickness becomes insufficient and holes are opened in the airtight space. Therefore, there is no danger that the SAW device will reduce its anti-dust and moisture resistance.
• FIG. 3 shows a process in which the resin sheet 30 temporarily bonded on each SAW chip 15 is placed in a sealing device 50 and brought into a vacuum state.
• the sealing device 50 includes a bottom heat source 52 and an upper heat source 53, a bottom exhaust port 54, and an upper exhaust port 55 in the chamber 51.
• a transport film 56 for transporting the SAW device is installed between the bottom heat source 52 and the upper heat source 53, and an elastic diaphragm is provided in the gap between the transport film 56 and the bottom heat source 52. It has a structure with 57 stretched.
• the mounting board base material 40 on which the resin sheet 30 is placed on the SAW chip 15 is placed in the transfer film 56, and the bottom heat source 52 and the top heat source 53 are used.
• the inside of the chamber 51 is heated and evacuated from the bottom exhaust port 54 and the upper exhaust port 55 to make the inside of the chamber 51 vacuum. Then, when the inside of the chamber 51 becomes a vacuum state, it is kept as it is.
• a step of laminating the resin sheet 30 on the outer surface of the SAW chip 15 is shown in FIG. First, the resin sheet 30 is heated to a temperature of 80 to 150 ° C. for a time of 1 to 10 minutes by the upper heat source 53 until the resin sheet 30 is gelled, so that the resin sheet 30 is in an optimal softened state. While heating, release to atmospheric pressure from bottom exhaust port 54. At this time, the upper exhaust port 55 side maintains the vacuum state.
• the resin sheet 30 is filled into the outer surface of the SAW chip 15 and the upper surface of the mounting substrate 40 by pressure.
• the resin sheet 30 is pressurized by releasing to the atmospheric pressure, but the resin sheet 30 may be pressurized by applying a pressure higher than the atmospheric pressure.
• the resin sheet is pressed against the SAW chip by expanding the diaphragm, but a flat plate or other pressing means may be used instead of the diaphragm.
• the pressure by opening the atmospheric pressure or higher than the atmospheric pressure By applying pressure to a flat plate or the like and pressing the flat plate against the resin sheet, the resin sheet is filled on the outer surface of the SAW chip and the upper surface of the mounting substrate base material.
• the resin after the laminating process is soft, and if simply heated at the resin curing temperature, the air in the hermetic space S expands and pushes out the resin, and the hermetic space expands more than necessary, so the resin is press-molded.
• the SAW chip 15 and the mounting substrate base material 40 laminated with the resin are kept heated and pressed in the laminating step, so that the diaphragm 57 becomes the SAW chip 15. Since it is deformed along the outer surface of the substrate and the upper surface of the mounting substrate 40 and pressed tightly, the resin can be molded and cured while maintaining the airtight space S.
• the post-curing step is a step in which the resin is heated at a temperature and time at which the resin is completely cured.
• the resin is heated at the resin curing temperature in the state shown in Fig.
• the mounting substrate base material 40 is taken out of the sealing device 50.
• the resin is completely sealed from the outer surface of the Saw chip 15 to the upper surface of the mounting substrate 40 as shown in FIG.
• the protective film 32 is peeled off, and the mounting board base material 40 is diced with a dicing blade along a dicing margin D shown in FIG. SAW device 1 is completed.
• the mounting substrate base material is taken out of the chamber 1, the mounting substrate base material is placed in a constant temperature layer, and the temperature and time at which the resin is completely cured are set.
• the resin may be cured by heating at.
• the entire process from the laminating process to the post-curing process can be performed consistently on the same device without using a separate device.
• the resin is SA
• FIG. 7 is a simplified diagram showing the steps from the arrangement of the substrate to the release of the atmospheric pressure in the laminating step according to the present invention.
• the mounting base material 40 on which the SAW chip 15 is mounted is placed in the chamber 51, and the inside of the chamber 51 is connected to the exhaust ports 54 and 55. After evacuating to a vacuum state, a resin sheet 30 is stuck on the top surface of the chip 15 and the resin sheet 30 is softened by releasing the inside of the chamber from the exhaust port 54 to the atmospheric pressure while softening the resin sheet 30. This is a procedure for pressing the sheet 30 to the SAW chip 15.
• the atmosphere in the chamber 1 may be replaced with an inert gas before the inside of the chamber 1 is evacuated.
• the airtight space after the resin sealing is completed is filled with the inert gas, so that the SAW device can be prevented from changing with time and its electrical characteristics can be maintained over time.
• the diaphragm at the time of lamination is used. Since the pressure applied to the SAW chip located at the outermost periphery of the SAW chip located at the center of the mounting board base material is higher than that of the SAW chip, part B in Fig. 5, that is, the outermost periphery of the mounting board base material There is a possibility that the amount of resin is reduced at the corners of the SAW chip located at, and the SAW chip is exposed to the outside.
• FIG. 8 is an enlarged view of the mounting substrate base material during the laminating step.
• Fig. 8 (a) shows that after mounting the SAW chips 15 on the mounting board base material 40 by flip-chip bonding, a resin sheet 30 is attached so as to straddle the upper surface of each SAW chip 15, and further, an annular shape is formed on the resin sheet 30. This is the state when the laminating step is performed with the frame 61 provided.
• the annular frame 61 has a thickness smaller than or similar to that of the SAW chip 15, and is arranged so as to surround the SAW chip 15 mounted on the mounting substrate base material 40.
• the mounting substrate preform 40 is disposed in the chamber, and the above-described laminating step is performed.
• the annular frame 61 is provided on the resin sheet 30, the deformation of the diaphragm 57 due to the pressure during the laminating step can be made to be a right angle in the portion C of FIG. 8A. Therefore, there is an effect that the thickness of the resin can be maintained regardless of the mounting position of the mounting substrate base material.
• a wall 62 having the same thickness as the SAW chip 15 is provided on the outer peripheral portion of the mounting substrate base material 40, As shown in FIG.
• a structure in which a flat plate 63 having an area larger than the area where the SAW chip 15 is mounted on the resin sheet 30 may be used. It is possible to suppress a decrease in the amount of resin of the SAW chip at the outermost periphery of the chip, thereby preventing external exposure of the SAW chip.
• FIG. 9 shows an enlarged view of the mounting base material during the laminating process.
• FIG. 9 (a) shows a structure in which a frame 71 is provided around each individual SAW chip 15 of the mounting substrate 40, and the frame 71 overlaps the periphery of the SAW chip 15. It is made of alumina or the like, and has a thickness smaller than the gap between the SAW chip 15 and the mounting substrate base material 40.
• FIG. 9 (b) shows a structure in which a dam 72 is provided on the mounting surface side of the SAW chip 15, and the dam 72 has an outer peripheral portion except for a portion where the IDT 17 of the SAW chip 15 is formed. It is formed of a photosensitive resin or the like so as to surround it, and has a thickness smaller than the gap between the SAW chip 15 and the mounting substrate base material 40. Specifically, the thickness of the dam 72 is set to 10 m or more and 30 m or less.
• FIG. 9C shows a structure in which a region other than the connection pad 5 on the mounting substrate preform 40 is covered with an insulating layer 73 of alumina or the like. Note that the thickness of the insulating layer 73 is smaller than the gap between the SAW chip 15 and the mounting substrate base material 40. Specifically, the thickness of the insulating layer 73 is 10 ⁇ m or more. m or less. Further, FIG. 9 (d) shows a case where a frame 74 is provided so as to overlap with the peripheral edge of each individual SAW chip 15 on the mounting substrate 40, and the portion where the IDT 17 of the SAW chip 15 is formed is shown. Except for this, a dam 75 is formed to surround the outer periphery.
• the frame and dam are almost heavy
• the sum of the thicknesses of the frame 74 and the dam 75 is made smaller than the gap between the SAW chip and the base material of the mounting board. Specifically, the sum of the thickness of the frame 72 and the dam is 30 m or less.
• the dam was formed of a photosensitive resin and the frame was formed of an insulator such as alumina.
• the present invention is not limited to this. Both the dam and the frame were formed of a photosensitive resin or metal or metal. You may form with an inorganic material of an insulator.
• the resin sealing step can be performed consistently. It is excellent in mass productivity because it is not necessary to prepare jigs for each device size.
• the SAW chip is sealed with a sufficiently thick resin to firmly protect it, preventing damage to the SAW chip and exposing the outer surface of the SAW chip, and providing excellent airtightness and moisture resistance S AW devices can be provided.

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• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

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• 2003
  • 2003-06-03 JP JP2003157888A patent/JP3689414B2/ja not_active Expired - Fee Related
• 2004
  • 2004-06-01 US US10/559,238 patent/US7183125B2/en not_active Expired - Fee Related
  • 2004-06-01 WO PCT/JP2004/007900 patent/WO2004109912A1/ja not_active Ceased
  • 2004-06-01 CN CN2004800154502A patent/CN1799194B/zh not_active Expired - Fee Related

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