JP2005117364A - Manufacturing method for surface acoustic wave device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a surface acoustic wave device whose yield is satisfactory by suppressing occurrence of air bubbles (void). <P>SOLUTION: This method comprises: a mounting process for mounting a plurality of surface acoustic wave elements 2 on an aggregate substrate 11 consisting of a plurality of mounting substrates, respectively; a sealing resin first coating process for coating a sealing resin 4b only on one side part each of the plurality of mounted surface acoustic wave elements 2, respectively by using a first mask 6 ; and a sealing resin second coating process for coating a sealing resin 4d on all of the parts of the plurality of mounted surface acoustic wave elements 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a surface acoustic wave device of a chip size package using a sealing resin, which can improve the yield.

  With recent downsizing and weight reduction of electronic devices, there is a demand for downsizing and weight reduction of electronic components. Against this background, the surface acoustic wave filter (hereinafter referred to as SAW filter) used as a surface acoustic wave device used in a communication device such as a mobile phone is also required to be reduced in size and weight. .

  A conventional surface acoustic wave device uses a surface acoustic wave element formed by forming a comb-shaped electrode (Inter-Digital Transducer, hereinafter referred to as IDT) on a piezoelectric substrate, and is flip-chip bonded or die bonded to a package material made of alumina. However, even if the surface acoustic wave element is downsized, the surface acoustic wave device cannot be downsized unless the package is downsized, and there is a limit to downsizing.

  Therefore, in recent years, surface acoustic wave devices with chip size packages have been proposed. The surface acoustic wave device of the chip size package has a surface acoustic wave element placed on the mounting substrate such that the surface of the piezoelectric substrate of the surface acoustic wave element on which the vibration part made of IDT is formed faces the mounting substrate. The surface acoustic wave element is mounted by a flip chip bonding method, and the mounted surface acoustic wave element is sealed with a sealing resin. That is, instead of the package structure having a package material, the surface acoustic wave element is sealed with a sealing resin, so that the size is reduced.

  In the manufacture of the surface acoustic wave device of the chip size package as described above, after mounting the surface acoustic wave element on the mounting substrate, the sealing resin can be applied by printing through the opening of the mask by rubbing with a squeegee. Done. When air bubbles are generated in the sealing resin when the sealing resin is applied, the IDT of the surface acoustic wave element is not blocked from the outside air by the air bubbles (voids). The characteristics will deteriorate. Therefore, Patent Documents 1 and 2 disclose a method of manufacturing a surface acoustic wave device having a chip size package without generating bubbles.

  In patent document 1, although it is a manufacturing method of a semiconductor device, after mounting a semiconductor element on a wiring board, a sealing resin is printed under reduced pressure conditions, and bubbles (voids) are generated in the sealing resin. Preventing is disclosed.

Patent Document 2 discloses a method for manufacturing a surface acoustic wave device having a chip size package. As shown in FIGS. 7 and 8, a plurality of surface acoustic wave elements are provided on a collective substrate 21 composed of a plurality of mounting substrates. It is disclosed that, after mounting 22 in a horizontal and vertical direction, by applying the sealing resin in two steps as follows, the generation of bubbles in the sealing resin can be prevented. Yes. Specifically, as shown in FIG. 7, in the first application of the sealing resin, the sealing resin is applied in a stripe pattern between the plurality of surface acoustic wave elements 22 adjacent along one arrangement direction. Then, as shown in FIG. 8, in the second application of the sealing resin, the resin is applied to the entire surface, so that a plurality of elasticity that is not applied by the first application of the sealing resin. It is disclosed that a sealing resin is applied between the surface wave elements 22.
Japanese Patent Laid-Open No. 11-040589 (Publication date: February 12, 1999) JP 2003-142972 A (publication date: May 16, 2003)

  However, in the manufacturing method described in Patent Document 1, since the resin is applied in a reduced-pressure atmosphere, it is possible to prevent bubbles from being generated in the sealing resin, but the sealing resin is a surface acoustic wave. There is a problem that it flows into a space formed between the element and the mounting substrate, and the characteristics of the surface acoustic wave device cannot be obtained.

  In the surface acoustic wave device, a space for exciting the surface acoustic wave is required on a portion made of IDT or the like formed on the piezoelectric substrate of the surface acoustic wave element. That is, when a surface acoustic wave device having a chip size package is manufactured, the sealing resin enters the space formed between the surface of the surface acoustic wave element where the IDT of the piezoelectric substrate is formed and the mounting substrate. It is necessary not to.

  Further, the production method described in Patent Document 2 cannot completely prevent the generation of bubbles. In the manufacturing method described in Patent Document 2, after the surface acoustic wave elements 22 are arranged vertically and horizontally and mounted on the collective substrate 21, as shown in FIGS. 7A and 7B, by the first application, A sealing resin is filled between the surface acoustic wave elements 22 adjacent to each other. At this time, the sealing resin is applied in a stripe pattern between the surface acoustic wave elements 22. For this reason, when the resin is applied to the whole second time, the sealing resin is applied by the first application, as shown in FIGS. 8A and 8B, regardless of which direction the resin is applied. Bubbles are easily bitten by the sealing resin applied between the surface acoustic wave elements 22 between the surface acoustic wave elements 22, and the generation of bubbles (voids) 34 a cannot be completely prevented.

  In order to solve the above problems, a method for manufacturing a surface acoustic wave device according to the present invention includes a surface acoustic wave element having a piezoelectric substrate and a vibrating portion including a comb-shaped electrode portion formed on the piezoelectric substrate. The surface acoustic wave device is mounted so that the vibrating portions of the surface acoustic wave element face each other, and the mounted surface acoustic wave element is sealed with a sealing resin, which includes a plurality of mounting substrates. A mounting step of mounting each of the plurality of surface acoustic wave elements on the collective substrate constituted by: a sealing resin first application step of respectively applying a sealing resin to one side of the mounted plurality of surface acoustic wave elements; And a sealing resin second application step of applying a sealing resin to the entirety of the plurality of mounted surface acoustic wave elements.

  In order to solve the above problems, another method of manufacturing a surface acoustic wave device according to the present invention includes a surface acoustic wave element having a piezoelectric substrate and a vibrating portion including a comb-shaped electrode portion formed on the piezoelectric substrate. A method of manufacturing a surface acoustic wave device, wherein the surface acoustic wave device is mounted on a mounting substrate so that the vibrating portions of the surface acoustic wave device face each other, and the mounted surface acoustic wave device is sealed with a sealing resin. A mounting step of mounting a plurality of surface acoustic wave elements on a collective substrate constituted by a mounting substrate, and a first mask having a first opening corresponding to one side of the mounted plurality of surface acoustic wave elements Sealing is performed using a sealing resin first application step in which the sealing resin is applied to the one side by printing, and a second mask having a second opening corresponding to the entirety of the plurality of mounted surface acoustic wave elements. Sealing that applies resin to the whole by printing It is characterized by having a fat second coating step.

  In the manufacturing method, it is preferable that the direction in which the sealing resin is applied in the second sealing resin application step is opposite to the direction in which the sealing resin is applied in the first sealing resin application step.

  According to the above method, the sealing resin can be formed on one side of the surface acoustic wave element by providing the sealing resin first application step, and thus the sealing resin is applied in the sealing resin second application step. In this case, it is possible to prevent the generation of bubbles (voids) in the side surface portion of the surface acoustic wave element that is substantially perpendicular to the application direction.

  That is, in the above method, when the sealing resin is applied in the second sealing resin application step, bubbles (voids) are generated due to air entrainment of the sealing resin at the side surface in the vertical direction in the surface acoustic wave element. ) Can be suppressed, so that a decrease in yield and a decrease in reliability due to the generation of bubbles (voids) can also be avoided.

  In particular, by setting the direction in which the sealing resin is applied in the second sealing resin application step to the direction in which the sealing resin is applied in the first sealing resin application step, the sealing resin first is set. In the coating process, the sealing resin formed on the upstream side in the coating direction is the downstream side in the coating direction of the sealing resin second coating process, that is, the portion where air entrapment easily occurs in the sealing resin second coating process. Therefore, the generation of bubbles can be more efficiently prevented.

  An embodiment of the method for manufacturing a surface acoustic wave device according to the present invention will be described below with reference to FIGS.

  First, the configuration of the surface acoustic wave device will be described. The surface acoustic wave device includes a ceramic substrate (mounting substrate) 1, a surface acoustic wave element 2, and a sealing resin 4, as shown in FIG. Have. The surface acoustic wave element 2 includes a substantially rectangular plate-like piezoelectric substrate 2a having a substantially rectangular parallelepiped shape, and a vibrating portion 2b made of IDT formed on the piezoelectric substrate 2a. The surface acoustic wave element 2 is mounted by a flip chip bonding method using the bumps 3 so that the vibration part 2b of the surface acoustic wave element 2 faces the surface of the ceramic substrate 1 with a space. Yes. In addition, in the surface acoustic wave device, the outer wall surfaces of the mounted surface acoustic wave element 2 and the exposed surface of the ceramic substrate are tightly sealed with a sealing resin 4. That is, the surface acoustic wave device is a surface acoustic wave device of a chip size package.

  In the surface acoustic wave device, the sealing resin 4 is formed so as to surround the periphery of the vibration part 2b on the formation surface of the vibration part 2b of the surface acoustic wave element 2, that is, along the outer edge of the formation surface. A dam portion 5 for preventing inflow into the space portion is formed so as to protrude outward at the same height in the substantially vertical direction from the formation surface. The dam portion 5 is preferably made of a resin having flexibility. The dam portion 5 may be formed on the surface acoustic wave element 2 or may be formed on the ceramic substrate 1.

  In this manufacturing method, as shown in FIGS. 1 (a) and 1 (b), a collective substrate 11 that is an aggregate of a plurality of mounting substrates is placed on the surface of the work table 9 (preferably a horizontal plane). And mounting the plurality of surface acoustic wave elements 2 on the collective substrate 11 at positions corresponding to the respective mounting substrates 1 and sealing the plurality of surface acoustic wave elements 2 mounted. It has an application (formation) step of forming the stop resins 4b and 4d so as to cover them by application, and a separation step (not shown) for separating the aggregate substrate into each mounting substrate by dicing or the like.

  And in this manufacturing method, the process which apply | coats and forms sealing resin 4b, 4d with respect to the several surface acoustic wave element 2 each mounted in the position corresponding to each said mounting substrate 1 on the collective substrate 11 is formed. Is characterized by being divided into two steps as described below.

  The 1st time (sealing resin 1st application process) is performed as follows. The surface acoustic wave element 2 has a rectangular shape (a rectangular parallelepiped shape), and the first opening 6a is provided at a position corresponding to a side surface portion (upstream side surface portion in the squeegee direction below) of one side of each surface acoustic wave element 2. The first mask 6 having the first mask 6 is placed on each surface acoustic wave element 2 and used. Next, the sealing resin material 4a on the first mask 6 is moved in one direction with the squeegee 7 (for example, along the longitudinal direction of the surface acoustic wave element 2). Rub to inject.

  Accordingly, in the above method, the sealing resin material 4a is placed in a tapered shape only on the side surface portion of one side of the surface acoustic wave element 2, and the sealing resin 4b is tapered only on the side surface portion. Form. In addition, it is preferable that the sealing resin 4b is formed in the whole side part, and it is desirable to cover the whole side part substantially.

  Even if the sealing resin 4b is placed so as not to reach the opposing side surface portion of the adjacent surface acoustic wave element 2, that is, in a separated state, the adjacent surface acoustic wave element 2 is also opposed. The sealing resin 4b may be placed so as to reach the side surface portion to be performed.

  The second time (sealing resin second application step) is performed as follows. As shown in FIG. 1B, a second mask 8 having a second opening 8a corresponding to the entire collective substrate 11 on which each surface acoustic wave element 2 is mounted is used, and sealing on the second mask 8 is performed. The surface acoustic wave element 2 and the surface acoustic wave element 2 are applied by applying the sealing resin material 4c by rubbing with the squeegee 7 from the direction opposite to the direction in which the resin material 4c is rubbed with the squeegee 7 when the first sealing resin material 4a is applied. A sealing resin 4d that covers the exposed surface of the collective substrate 11 is formed. The surface of the sealing resin 4 d is preferably set to be flush with the surface of the collective substrate 11.

  For ease of explanation, the sealing resins 4b and 4d are illustrated separately, but are actually made of the same material and are integrated as the sealing resin 4. That is, in this embodiment, the same resin is used for the sealing resin materials 4a and 4c and the sealing resins 4b and 4d.

  In the method of the present invention, when the sealing resin material 4c is applied by printing the sealing resin materials 4a and 4c in two steps, each surface acoustic wave element 2 on the downstream side in the squeegee direction is applied. Since the sealing resin 4b is present on each of the side surfaces, the generation of bubbles (voids) can be prevented in the sealing resins 4b and 4d formed by application. The formation of the sealing resin 4b for the first time is not limited to the printing method using the squeegee 7, but may be a dispensing method in which injection is performed using a needle-like dispenser.

  The production method of the present invention will be described more specifically. First, a first mask that is a first printing mask for resin coating and a second mask that is used as a second printing mask for resin coating used in a general screen printer. Prepare a mask and each.

  At this time, as shown in FIGS. 3 and 4, the first mask 6 is opened so that only one side (side surface portion) of the side surface of the surface acoustic wave element 2 can be applied. The size of the first opening 6 a is smaller than the size of the surface acoustic wave element 2, and the opening area is preferably in the range of 4% to 24% of the surface area of the surface acoustic wave element 2. On the other hand, as shown in FIG. 5, the second mask 8 is provided with a second opening 8 a that is open so that the entire aggregate substrate 11 can be applied.

  Thereafter, in the squeegee printing method, as shown in FIG. 4A, the first mask 6 is applied to each elastic so that the sealing resin material 4 a is applied only to one side of the surface acoustic wave element 2. Each surface acoustic wave element 2 is placed on the surface wave element 2 and the sealing resin material 4a on the first mask 6 is scanned in one direction in the squeegee 7 as shown in FIG. The sealing resin 4b is placed on the side (side surface portion) on the upstream side in the first scanning direction. At this time, the sealing resin 4b may or may not be cured.

  Next, in the squeegee printing method, the second mask 8 is placed as shown in FIG. 5, and as shown in FIG. The sealing resin material 4c is applied, and each surface acoustic wave element 2 is covered with the sealing resin 4d. The squeezing direction during the second scan is opposite to the squeegee direction during the first scan (FIGS. 1A and 1B). Thereafter, the sealing resins 4b and 4d are cured at a predetermined temperature and time.

  As a comparative example, as shown in FIG. 6, when the sealing resin 4 d is applied only by solid coating on the entire surface (that is, only in the second time), the surface acoustic wave element 2 is perpendicular to the squeegee direction. Bubbles (voids) 4e due to air entrainment were generated at the position (side surface portion of the surface acoustic wave element 2 on the downstream side in the squeegee direction) (occurrence rate: 40% to 80%).

  However, if the sealing resin 4b is applied in advance to the position where the previous bubble (void) is generated in the first application (applied only to the side portion of one side), the occurrence of bubble (void) failure is 1%. It became the following. The ratio of the area (application area) of the first opening 6a of the first mask 6 used for the first time is set within the range of 4% to 24% of the surface area of the surface acoustic wave element 2 (surface area of the IDT formation surface). Thus, the sealing resin 4b can be applied only to the one side portion.

  Depending on the viscosity of the sealing resin material to be used, the area of the first opening 6a of the first mask 6, and the application temperature, there is a range where inflowing bubbles can be suppressed, and the setting range is described below. The above problems could be improved.

  The sealing resin material used has a viscosity of 300 Pa · s to 800 Pa · s, the opening area of the first opening 6a of the first mask 6 is set to 4% to 24% of the surface area ratio of the surface acoustic wave element, and the coating temperature When the temperature was set to 40 ° C. to 50 ° C., the inflow of the sealing resin material to the IDT formation surface could be prevented (occurrence rate 0%), and the generation of bubbles (voids) could be suppressed (occurrence rate 1.0%).

  When bubbles (voids) are generated, the functional part (vibration part) of the surface acoustic wave element 2 is not blocked from the outside air, resulting in characteristic deterioration. Further, the yield is deteriorated in the leak inspection for detecting it.

  By the way, in the prior art described in Patent Document 2, as described above, bubbles are easily generated.

  However, in the present invention, first, the sealing resin 4b is applied to only one side of the surface acoustic wave element 2, and then the sealing resin 4d is overcoated from the opposite direction so that it can be applied while extruding air. Generation of air bubbles (voids) can be prevented.

  The method for manufacturing a surface acoustic wave device of the present invention can suppress the generation of bubbles in the sealing resin when mass-producing surface acoustic wave devices of chip size packages using the sealing resin. Thus, the yield of the obtained surface acoustic wave device can be improved, and the surface acoustic wave device can be suitably used for mass production of chip size packaged surface acoustic wave devices.

It is sectional drawing of each process in the manufacturing method of the surface acoustic wave apparatus of this invention, Comprising: (a) shows a 1st application process, (b) shows a 2nd application process. It is sectional drawing of the said surface acoustic wave apparatus of a resin sealing type. It is a top view of the 1st mask used for the said manufacturing method. It is a top view which shows the usage method of the 1st mask to each surface acoustic wave element in the said 1st application | coating process, (a) shows before application | coating and (b) shows after application | coating. It is a top view which shows the usage method of the 2nd mask to each surface acoustic wave element in the said 2nd application | coating process. It is a top view which shows the result (bubble generation | occurrence | production) of the application | coating process to each surface acoustic wave element in the manufacturing method of a comparative example. 1 shows one process of a conventional manufacturing method, (a) shows a plan view of a process in which a sealing resin material is applied in a striped pattern in one direction between each surface acoustic wave element, and (b) shows the above process. A cross-sectional view is shown. The other process of the said conventional manufacturing method is shown, (a) is the plane of the process which apply | coated the sealing resin material along the said other direction in the stripe form of the other direction between each surface acoustic wave element. FIG. 4B is a plan view of a process in which a sealing resin material is applied in a stripe shape in the other direction between the surface acoustic wave elements in a direction perpendicular to the other direction.

Explanation of symbols

2: Surface acoustic wave element 2a: Piezoelectric substrate 2b: Vibrating part (comb electrode part, IDT)
4a, 4c: sealing resin material 4b, 4d: sealing resin 6: first mask 6a: first opening 8: second mask 8a: second opening

Claims (3)

A surface acoustic wave element having a piezoelectric substrate and a vibration part formed of a comb-shaped electrode part formed on the piezoelectric substrate is mounted on a mounting substrate so that the vibration part of the surface acoustic wave element faces the mounting part. A method of manufacturing a surface acoustic wave device in which a surface acoustic wave element is sealed with a sealing resin,
A mounting step of mounting a plurality of surface acoustic wave elements on a collective substrate composed of a plurality of mounting substrates,
A sealing resin first application step of applying a sealing resin to one side of the plurality of mounted surface acoustic wave elements,
A method of manufacturing a surface acoustic wave device, comprising: a sealing resin second application step of applying a sealing resin to a plurality of mounted surface acoustic wave elements. A surface acoustic wave element having a piezoelectric substrate and a vibration part formed of a comb-shaped electrode part formed on the piezoelectric substrate is mounted on a mounting substrate so that the vibration part of the surface acoustic wave element faces the mounting part. A method of manufacturing a surface acoustic wave device in which a surface acoustic wave element is sealed with a sealing resin,
A mounting step of mounting a plurality of surface acoustic wave elements on a collective substrate composed of a plurality of mounting substrates,
A sealing resin first application step of applying a sealing resin to the one side part by printing using a first mask having a first opening corresponding to one side part of the plurality of mounted surface acoustic wave elements;
And a sealing resin second application step of applying the sealing resin to the whole by printing using a second mask having a second opening corresponding to the whole of the plurality of mounted surface acoustic wave elements. A method for manufacturing a surface acoustic wave device. The direction in which the sealing resin is applied in the second sealing resin application step is opposite to the direction in which the sealing resin is applied in the first sealing resin application step. A method for producing the surface acoustic wave device according to claim 1.

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