JP4555068B2 - Method for manufacturing crystal resonator package - Google Patents

Description

  The present invention relates to a method for manufacturing a quartz resonator package that is covered and sealed with a cover made of glass or the like.

  Piezoelectric elements such as quartz resonators are susceptible to breakage due to subtle changes in characteristics due to changes in ambient temperature and humidity, or due to minute foreign matter, and mechanical vibration and impact. For this reason, the element mentioned above is sealed for use in a package. The package system is divided into a hermetic sealing system and a simple sealing system using a resin. In the SMD (Surface Mounted Device) type hermetic sealing system, materials such as ceramics and metals are mainly used. Further, as a cheaper hermetic sealing method, a hermetic sealing plastic package using plastic has also been realized.

  In addition, an airtight package has been proposed in which a crystal resonator piece and an outer frame are integrally formed from a quartz substrate, and a lid and a case made of glass or the like are anodically bonded at the outer frame (see Patent Document 1). According to the technique of Patent Document 1, a smaller package is realized, and in addition, solder and low-melting glass are not used for joining the lid and the case, so that the problem of adhesion of outgas to the crystal unit piece is suppressed. And higher airtightness can be obtained.

  In addition, a technique has been proposed in which a plurality of elements are simultaneously formed at a wafer level so as to be sealed and then cut into individual elements (chips) to form a packaged chip (Patent Literature). 2). In this technique, a glass wafer is bonded to a crystal wafer on which a plurality of crystal resonator bodies are formed, and a portion of the crystal resonator body is sealed.

  Here, a method for manufacturing a package sealed in a wafer state will be briefly described. First, as shown in FIG. 5, each electrode and wiring are formed on a plurality of chip portions formed on the crystal wafer 101. As shown in FIG. 5, the plurality of chip portions formed on the quartz wafer 101 includes a frame portion 110 and a quartz resonator element 111 formed by hollowing out the periphery. In addition, the opening 102 is formed in a region corresponding to the four corners of the frame 110, and the four corners 110 a, 110 b, 110 c, and 110 d of the frame 110 protrude to the inside of the opening 102. Yes. Here, FIG. 5B is a cross-sectional view schematically showing a cross section taken along line BB ′ in FIG. 5A, and FIG. 5C is a cross section taken along line CC ′ in FIG. It is sectional drawing which showed typically.

  As shown in each cross-sectional view, the crystal unit piece 111 is fixed to the frame unit 110 by the connecting portion 113 and the connecting unit 114, and the crystal unit piece 111 has electrodes 121 and 131 on both surfaces. Is formed. The electrode 121 provided on one surface of the crystal resonator element 111 is provided at a corner portion 110 b on one surface of the frame portion 110 via a wiring (first wiring) 122 provided on the connecting portion 113. Connected to the peripheral adjustment terminal 523. The electrode 131 provided on the other surface of the frame portion 110 is connected to the wiring (second wiring) 132 provided on the other surface of the connecting portion 114 and the side wiring 533 provided on the side surface of the connecting portion 114. , And connected to a peripheral terminal 524 provided at a corner 110a of one surface of the frame 110.

  As shown in FIG. 5, after the two peripheral terminals are formed on one surface, before the glass wafer is bonded, the peripheral terminals 523 and the peripheral terminals 524 of each chip portion are used. The frequency is adjusted for each part. Next, by removing the side wiring 533, the electrical connection between the wiring 132 and the peripheral terminal 524 is cut off as shown in the cross-sectional view of FIG. FIG. 6 corresponds to the cross section taken along the line CC ′ of FIG.

  Next, as shown in FIG. 7A, the metal layer 534 is formed on one surface of the frame 110, and the other surface of the frame 110 is shown in FIG. 7B. In this state, a metal layer 535 is formed. The metal layer 534 and the metal layer 535 function as a bonding film for bonding a cover described below by anodic bonding, and also function as wiring for connecting the electrode 121 and the electrode 131 to terminals provided outside the cover. To do. Here, on one surface of the frame part 110 shown in FIG. 7A, the peripheral terminal 523 and the peripheral terminal 524 are electrically connected by the metal layer 534. However, the circumferential adjustment terminal 524 is not electrically connected to the wiring 132 provided in the connecting portion 114 on the other surface of the frame portion 110. Therefore, even if the metal layer 534 and the metal layer 535 are formed, the electrode 121 and the electrode 131 are not electrically connected.

  Next, as shown in the perspective view of FIG. 8A, a glass wafer 140 having a plurality of circular openings 102a and a glass wafer 150 having a plurality of circular openings 102b are prepared. . The glass wafer 150 has a plurality of recesses 150b. Although not shown in FIG. 8, the glass wafer 140 is similarly formed with a plurality of recesses. The openings 102 a and 102 b are formed in the same arrangement as the openings 102 provided in the crystal wafer 101. For example, when the glass wafer 140 and the quartz wafer 101 are bonded together, the center of the opening 102 overlaps the center of the opening 102b as shown in the plan view of FIG. 8B. In addition, the corner 110a, the corner 110b, the corner 110c, and the corner 110d protruding inside the opening 102 are exposed in the opening of the circular opening 102b.

  The glass wafer 140 and the glass wafer 150 thus formed are anodically bonded by the metal layer 534 and the metal layer 535 formed on the frame portion 110, whereby the glass wafer 140 and the glass wafer 150 are bonded to the crystal wafer 101 ( A state of being bonded to the frame portion 110) is obtained. In the bonded state, in each chip region, the crystal resonator element 111 is sealed in a space formed by the frame 110, the recess 140 b of the glass wafer 140, and the recess 150 b of the glass wafer 150. It will be in the state.

  Further, in the bonded state, the respective opening portions 102a, the opening portions 102, and the opening portions 102b are in communication with each other, and the corner portions 110a protrude in the communication holes. Further, the metal layer 534 formed in the frame part 110 and the part of the metal layer 535 extending to the corner part 110b (corner part 110a) and the corner part 110d (corner part 110c) It will be in an exposed state.

  Next, a metal film is formed on the outer surface of the glass wafer 140 including the above-described communicating holes, and a terminal is formed by the formed metal film. At this time, the side wiring for connecting each terminal, the metal layer 534, and the metal layer 535 is formed on the inner surface of the communication hole formed by the opening 102a, the opening 102, and the opening 102b. .

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
Japanese Patent No. 3390348 JP 2003-188436 A

  By the way, the place where the peripheral terminal 523 and the peripheral terminal 524 are provided on one surface of the frame part 110 is in a state in which a metal layer 534 is laminated and a step is formed with another region. For this reason, when the glass wafer 140 is anodically bonded to the metal layer 534 formed on the quartz wafer 101, there is a problem that it is not easy to ensure airtightness at the stepped portion.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to eliminate air gaps on the surfaces to be joined so that airtightness can be secured more easily.

  The method for manufacturing a crystal resonator package according to the present invention includes a plurality of substantially rectangular pieces in which a frame portion and a crystal resonator piece disposed inside the frame portion are integrally formed via a first connecting portion and a second connecting portion. A step of preparing a crystal wafer in which the chip portion is disposed through a cutting region, a first electrode is formed on a first main surface of the crystal resonator piece, and a second portion of the crystal resonator piece is formed. A step of forming a second electrode on the main surface, a first wiring disposed in the first connecting portion and connected to the first electrode, and a frame portion continuously disposed in the circumferential direction. The first metal layer connected to the first metal layer, the first peripheral terminal disposed in the cutting region and connected to the first metal layer, and the first metal layer and the first peripheral terminal disposed in the cutting region are insulated and separated. A step in which the second circumferential terminal is formed by the same metal layer on the first main surface side, and a second connection The second wiring connected to the second electrode and connected to the second electrode, the second metal layer arranged continuously in the circumferential direction on the frame and connected to the second electrode, and the second metal layer arranged in the cutting region The step of setting the third wiring to be connected to be in the state formed of the same metal layer on the second main surface side, and the state of forming the fourth wiring for connecting the second circumferential terminal and the third wiring are formed. The step of adjusting the frequency of the crystal resonator piece on which the first electrode and the second electrode are formed using the step, the first peripheral terminal and the second peripheral terminal, and the first glass wafer is at least the first A step of joining the first main surface of the crystal wafer by the metal layer, a step of joining the second glass wafer to the second main surface of the crystal wafer by at least the second metal layer, In a state where the first glass wafer and the second glass wafer are bonded to the quartz wafer, By cutting to remove court area, in which a plurality of chips portion is so provided at least a step of a state of being cut individually.

  Therefore, in a state where the glass wafer is bonded and cut into individual chip portions as a result of cutting, the metal layer serving as the bonded portion has no step. Note that the through hole may be formed in the cutting region, and the fourth wiring may be formed on the inner side surface of the through hole. Bonding may be performed by anodic bonding.

  As described above, according to the present invention, each circumferential terminal is disposed in the cutting region, and each circumferential terminal and each electrode are connected to each other by a metal layer serving as a joint portion disposed in the frame portion. Therefore, in the frame portion, there is no step in the metal layer serving as the joining portion, and an excellent effect that the airtightness can be easily secured is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1, 2, and 3 show an example of a method for manufacturing a crystal resonator package according to an embodiment of the present invention, and schematically show the state in each step. FIG. 1 is a plan view, and FIG. 1 (a) shows one surface, and the other surface on the opposite side is shown in FIG. 1 (b). 2 and 3 are cross-sectional views.

  First, as shown in FIG. 1A, a plurality of frame portions 110 and crystal resonator elements 111 are formed on a crystal wafer 101, and openings 102 are formed in regions corresponding to the four corners of the frame portion 110. It is assumed that it is formed. Each of these chip portions is arranged substantially squarely via the cutting region 103. Further, in each chip part, the crystal resonator element 111 is disposed inside the frame part 110 and is fixed by the connecting part 113 and the connecting part 114. Accordingly, the frame portion 110 and the crystal resonator element 111 are integrally formed as a substantially rectangular crystal substrate.

  The opening 102 is formed such that the four corners 110 a, 110 b, 110 c, and 110 d of the frame 110 protrude to the inside of the opening 102. In addition, a through hole 104 is formed at a predetermined location in the cutting area 103. These can be formed by processing the quartz wafer 101 by a known photolithography technique and etching technique.

  Next, as shown in FIG. 1A, on one surface side of the crystal wafer 101, the wiring 122 passing through the connecting portion 113, the metal layer 123 disposed in the frame portion 110, and the metal layer 123 are connected. It is assumed that the peripheral terminal 124 disposed in the cutting region 103 and the peripheral terminal 125 disposed in the cutting region 103 are formed. However, the circumferential terminal 125 is insulated and separated from the metal layer 123. In these methods, for example, an aluminum film is formed on the entire surface of one surface of the quartz wafer 101 by sputtering or vacuum deposition, and the formed aluminum film is patterned by a known photolithography technique and etching technique. Thus, the wiring 122, the metal layer 123, the peripheral terminal 124, and the peripheral terminal 125 can be formed. Here, the metal layer 123 is continuously arranged in the circumferential direction of the frame portion 110. In addition, the wiring 122, the metal layer 123, the peripheral terminal 124, and the peripheral terminal 125 are formed from the same metal layer, and there is no step from the frame part 110 to the cutting region 103.

  Similarly, as shown in FIG. 1B, on the other surface side of the crystal wafer 101, the wiring 132 passing through the connecting portion 114, the metal layer 133 disposed in the frame portion 110, and the cutting region are disposed. Then, a wiring (third wiring) 133a connected to the metal layer 133 is formed. In these methods, for example, an aluminum film is formed on the entire other surface of the crystal wafer 101 by sputtering or vacuum deposition, and the formed aluminum film is patterned by a known photolithography technique and etching technique. Thus, the wiring 132, the metal layer 133, and the wiring 133a can be formed. Here, the metal layer 133 is continuously arranged in the circumferential direction of the frame portion 110. Further, the wiring 132, the metal layer 133, and the wiring 133a are formed from the same metal layer, and there is no step from the frame portion 110 to the cutting region 103.

  Here, as shown in FIGS. 2B and 2C, the wiring 133 a formed on the other surface of the frame portion 110 is replaced with the through wiring (fourth wiring) 133 b formed in the through hole 104. And connected to a peripheral terminal 125 formed on one surface. Therefore, the circumferential terminal 124 and the circumferential terminal 125 are arranged on one surface on which the electrode 121 is formed. The through wiring 133b formed on the inner side surface of the through hole 104 is formed, for example, by forming an aluminum film on the inner side surface of the through hole 104 in forming an aluminum film for forming the metal layer 123. Is possible. 2A shows a cross section taken along line BB ′ in FIG. 1, FIG. 2B shows a cross section taken along line CC ′ in FIG. 1A, and FIG. 2C shows FIG. The cross section of DD 'line of (a) is shown.

  As described above, after the electrodes and wirings are formed, the frequency adjustment is performed using the peripheral terminal 124 and the peripheral terminal 125. In this frequency adjustment, the probe is brought into contact with the portion arranged in the region of the trimming region 124 of the peripheral terminal 124 and the peripheral terminal 125, thereby scratching the joint region described below. So that there is no. By doing in this way, the state in which the metal layer formed in the region of the frame part 110 to be bonded is not damaged can be obtained, and the bonding can be performed in a better state.

  Next, as described with reference to FIG. 8, a glass wafer 140 having a plurality of circular openings 102a and a glass wafer 150 having a plurality of circular openings 102b are prepared. The glass wafer 150 has a plurality of recesses 150b. Although not shown in FIG. 8, the glass wafer 140 is similarly formed with a plurality of recesses 140b. The openings 102 a and 102 b are formed in the same arrangement as the openings 102 provided in the crystal wafer 101. For example, when the glass wafer 140 and the quartz wafer 101 are bonded together, the center of the opening 102 overlaps the center of the opening 102b as shown in the plan view of FIG. 8B. In addition, the corner 110a, the corner 110b, the corner 110c, and the corner 110d protruding inside the opening 102 are exposed in the opening of the circular opening 102b.

  The glass wafer 140 thus formed is anodically bonded to a bonding film composed of the metal layer 123, the peripheral terminal 124 and the peripheral terminal 125, and the glass wafer 150 is anodically bonded to the bonding film composed of the metal layer 133 and the wiring 133a. By doing so, a state in which the glass wafer 140 and the glass wafer 150 are bonded to the frame portion 110 (crystal wafer 101) is obtained. For example, if the glass wafer 140, the crystal wafer 101, and the glass wafer 150 are stacked in this order, and the same potential is applied to the metal layer 123 and the metal layer 133 and anodic bonding is performed, three wafers are bonded simultaneously. it can.

  In the bonded state, in each chip region, the crystal resonator element 111 is sealed in a space formed by the frame 110, the recess 140 b of the glass wafer 140, and the recess 150 b of the glass wafer 150. It will be in the state. For example, in a state where the wafers are in contact with each other for anodic bonding, these are placed in a vacuum exhaust atmosphere, and thereafter, the sealed space is evacuated by anodic bonding. It can be. Similarly, anodic bonding in a state where the gas is disposed in an inert gas atmosphere provides a state where the sealed space is filled with the inert gas.

  As described above, the metal layer 123, the circumferential terminal 124, and the circumferential terminal 125 are not stepped from the frame part 110 to the cutting region 103. Similarly, the wiring 132, the metal layer 133, and the wiring 133 a are in a state without a step from the frame portion 110 to the cutting region 103. Therefore, the airtightness of the above-described space can be easily obtained by bonding using these as bonding films. In addition, you may make it obtain not only anodic bonding but the state joined by the other method. Moreover, you may make it use the wafer which consists of not only glass but another member.

  Further, in the bonded state, the respective opening portions 102a, the opening portions 102, and the opening portions 102b are in communication with each other, and the corner portions 110a protrude in the communication holes. Further, the corner 110b portion of the metal layer 123 formed in the frame portion 110 and the corner 110d portion of the metal layer 133 are exposed in the communicating hole.

  Next, a metal film is formed on the outer surface of the glass wafer 140 including the inside of the above-described communicating holes, and the terminal 141 and the terminal 142 are formed by the formed metal film as shown in FIG. To do. At this time, the side wiring 126 and the side wiring 135 for connecting the terminal 141 and the metal layer 123 and the terminal 142 and the metal layer 133 are formed on the inner surface of the communication hole. In this state, the electrode 121 is connected to the terminal 141 through the path of the wiring 122 -the metal layer 123 -the side wiring 126. Further, the electrode 131 is connected to the terminal 142 through a path of the wiring 132 -the metal layer 133 -side wiring 135.

  As described above, after the glass wafer 140 and the glass wafer 150 are bonded to the frame 110 (the quartz wafer 101), the bonded glass wafer 140, the quartz wafer 101, and the glass wafer are bonded. By cutting out from 150 to individual chips, individual chip portions are formed. For example, if the lattice-shaped cutting region 103 passing through each opening 102 is cut out by a dicing technique using a diamond blade, a state in which individual chip portions are formed can be obtained.

  By the way, in the above description, the through hole 104 is provided, and the wiring 133 a formed on the other surface of the frame portion 110 is connected to the peripheral terminal 125 formed on one surface by the through wiring 133 b formed in the through hole 104. Although connected, it is not limited to this. As shown in the plan view of FIG. 4, the wiring formed on the other surface of the frame portion 110 by the side wiring (fourth wiring) 401 provided on the side surface of the cutting region 103 exposed in the opening 102. 133a may be connected to a peripheral terminal 125 formed on one surface.

  Further, in the cutting region 103, a gap may be provided on the cutting region 103 between the metal layers 123 of the adjacent chip portions and between the metal layers 133 of the adjacent chip portions. By providing the gap, the metal layer 123 provided on one surface and the metal layer 133 provided on the other surface are separated from each other for each chip portion. It is possible to adjust the frequency with a small stray capacitance for each chip portion. In this case, for example, after performing the frequency adjustment, the anodic bonding may be performed after forming the wiring connecting the gaps in the cutting region 103. When such a wiring is provided, a step is formed at a portion where the wiring is connected to the metal layer. However, the step is disposed in the cutting region 103, and the frame portion 110 is maintained without a step. In addition, due to the presence of the step, for example, when the above-described vacuum exhaust state is established, a gap corresponding to the step is formed between the wafers. In addition, it is not necessary to provide a gap between the wafers with other equipment such as spacers or jigs, and this can be done more quickly.

It is a top view which shows the state of the one part process in the manufacturing method example of the crystal oscillator package in embodiment of this invention. It is sectional drawing which shows the state of the one part process in the example of the manufacturing method of the crystal oscillator package in embodiment of this invention. It is sectional drawing which shows the state of the one part process in the example of the manufacturing method of the crystal oscillator package in embodiment of this invention. It is a top view which shows the state of the one part process in the other example of a manufacturing method of the crystal oscillator package in embodiment of this invention. It is the top view (a), sectional drawing (b), and sectional drawing (c) which show the state of the middle process in the manufacturing method of the conventional quartz oscillator package. It is sectional drawing which shows the state of the middle process in the manufacturing method of the conventional quartz oscillator package. It is a top view which shows the state of the halfway process in the manufacturing method of the conventional quartz oscillator package. It is the perspective view (a) and the top view (b) which show the state of the middle process in the manufacturing method of the conventional crystal oscillator package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Quartz wafer, 102 ... Opening part, 103 ... Cutting area, 104 ... Through-hole, 110 ... Frame part, 111 ... Quartz vibrator piece, 113, 114 ... Connection part, 121 ... Electrode, 122 ... Wiring, 123 ... Metal Layer, 124 ... peripheral terminal, 125 ... peripheral terminal, 126 ... side wiring, 131 ... electrode, 132 ... wiring, 133 ... metal layer, 133a ... wiring, 133b ... through wiring, 135 ... side wiring, 140, 150 ... Glass wafer, 140b, 150b ... Recess, 141, 142 ... Terminal.

Claims (2)

The frame portion and the crystal resonator piece disposed inside the frame portion include a plurality of substantially rectangular chip portions integrally formed via the first connection portion and the second connection portion, and the chip portion defines the cutting region. Preparing a quartz wafer arranged via,
A step of forming a first electrode on a first main surface of the crystal resonator piece and forming a second electrode on a second main surface of the crystal resonator piece;
A first wiring disposed on the first connecting portion and connected to the first electrode; a first metal layer continuously disposed on the frame portion in the circumferential direction and connected to the first electrode; and the cutting region. A first tuned terminal disposed and connected to the first metal layer; and a second tuned terminal disposed in the cutting region and insulated from the first metal layer and the first tuned terminal; A step of forming the same metal layer on the first main surface side;
A second wiring arranged in the second connecting portion and connected to the second electrode; a second metal layer arranged continuously in the circumferential direction on the frame portion and connected to the second electrode; and the cutting region A third wiring connected to the second metal layer is formed on the second main surface side by the same metal layer; and
A step of forming a fourth wiring connecting the second circumferential terminal and the third wiring;
Adjusting the frequency of the crystal unit piece in which the first electrode and the second electrode are formed using the first peripheral terminal and the second peripheral terminal;
A step of bringing the first glass wafer into a state of being bonded to the first main surface of the quartz wafer by at least the first metal layer;
A step of bringing the second glass wafer into a state of being bonded to the second main surface of the crystal wafer by at least the second metal layer;
A step of cutting a plurality of the chip portions individually by cutting so as to remove the cutting region in a state where the first glass wafer and the second glass wafer are bonded to the crystal wafer. A method for manufacturing a crystal resonator package, comprising: In the manufacturing method of the crystal oscillator package according to claim 1,
A step of forming a through hole in the cutting region;
And a step of forming the fourth wiring on the inner side surface of the through-hole.

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