JP2002290183A - Manufacturing method of saw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a SAW device which restricts the deformations of a frame or a lid, by developing within a short time. SOLUTION: The method is provided with a first process for forming an IDT 12 and a connection electrode 13 on the front surface of a piezoelectric baseboard 11, a second process for adhering a photosensitive resin film onto the front surface of the piezoelectric baseboard 11, exposing the developing it and forming the frame 14 which encloses the outer peripheral part of the IDT 12; a third process for making the photosensitive resin film readhere onto the front surface of the piezoelectric resin film, exposing the developing it, forming the lid 15 on the frame 14 and covering the IDT 12 by the frame 14 and the lid 15; and a fourth process for arranging a seal resin 18 for covering the outer periphery of the frame 14 and the lid 15. At least a development in the second process or the third process is conducted by injecting developer, while having the piezoelectric baseboard 11 rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for manufacturing a SAW device used for a wireless communication device such as a cellular phone.

[0002]

2. Description of the Related Art Conventionally, a method for manufacturing a highly reliable SAW device that does not require a container-shaped package is disclosed in
What is described in 0-270975 is known.

FIG. 13 is a cross-sectional view of a conventional SAW device, wherein 1 is a piezoelectric substrate, 2a is an interdigital transducer (hereinafter referred to as IDT) provided on the piezoelectric substrate 1, 2b is a connection electrode of the IDT 2a, and 3 is a piezoelectric substrate. A frame 4 provided on the substrate 1 so as to surround the IDT 2a, 4 is a lid provided to seal the IDT 2a with the piezoelectric substrate 1 and the frame, and 5 is a SAW element provided with the piezoelectric substrates 1 to 4 ,
6 is a bump formed on the connection electrode 2b, 7 is a circuit board,
Reference numeral 8 denotes an external electrode, and 9 denotes a sealing resin that covers the entire electrode forming surface of the SAW element 5.

A method for manufacturing this SAW device will be described. First, a plurality of IDs are provided on the surface of the large-sized piezoelectric substrate 1.
T2a and the connection electrode 2b are formed. Next, a frame 3 is formed on the piezoelectric substrate 1 by a photolithography method using a photosensitive resin film so as to surround the outer periphery of the IDT 2a.

Next, a lid 4 is formed by a photolithography method using a photosensitive resin film so as to cover the upper part of the frame 3 and the IDT 2a. After that, the piezoelectric substrate 1 is cut into individual SAW elements 5, bumps 6 for connecting to the external electrodes 8 are formed on the connection electrodes 2 b, and the sealing resin 9 is filled after joining to the external electrodes 8 of the circuit board 7. To obtain a SAW device.

[0006] In this manufacturing method of the SAW device, a developing method in a step of forming the frame 3 and the lid 4 is not specified, but a developing method of a photosensitive resin film in an electronic component such as a SAW device is shown in FIG. 14 and Figure 1
Generally, there are two types as shown in FIG.

In FIG. 1, reference numeral 200 denotes a developing solution, 201 denotes a first support, 202 denotes a second support, 203 denotes a piezoelectric substrate,
05 is a belt conveyor, 206 is a support, 207 is a piezoelectric substrate, 208 is a nozzle, and 209 is a developer.

The first method is as shown in FIG.
And the piezoelectric substrate 2 held by the second supports 201 and 202
03 is immersed in a developing solution 200 and guided up and down to swell and dissolve unnecessary photosensitive resin.

Another method, as shown in FIG. 15, is to move a piezoelectric substrate 207 installed on a belt conveyor 205 via a support body 206 through a developing solution 209 sprayed from a nozzle 208 provided below, thereby making unnecessary. This is an upward injection method that swells and dissolves a photosensitive resin.

[0010]

If any of these two methods is applied to the above-described method for manufacturing a SAW device, the time required for development is long, and the time during which the photosensitive resin film is in contact with the developing solution is long. There has been a problem that the photosensitive resin film swells to deform the frame and the lid, which adversely affects the characteristics of the SAW device. In particular, the deformation of the lid was remarkable.

An object of the present invention is to provide a method of manufacturing a SAW device which can suppress deformation of a frame and a lid by performing development in a short time.

[0012]

Means for Solving the Problems In order to achieve the above object, the present invention has the following arrangement.

[0013] The invention described in claim 1 of the present invention is, in particular,
At least one of the frame and the lid formed using the photosensitive resin film is developed by spraying a developer while rotating the piezoelectric substrate, and the photosensitive resin swelled and dissolved by the developer. Is removed by the centrifugal force caused by the rotation of the piezoelectric substrate together with the developing solution, and swelling, dissolving, and removing are constantly repeated, so that development is completed in a short time, and deformation of the frame or the lid can be suppressed.

[0014] The invention described in claim 2 of the present invention is, in particular,
The injection of the developer is performed using a linear nozzle or a fan-shaped nozzle.By jetting the developer in a linear or fan shape, the injection pressure of the developer becomes stronger compared to a charged conical nozzle, etc. The swelling and dissolving of the photosensitive resin are sufficiently performed, and the developer area deposited on the piezoelectric substrate is small due to the small spray area, and the spray pressure is sufficiently applied to the piezoelectric substrate. And the residue of the photosensitive resin can be reduced.

[0015] The invention described in claim 3 of the present invention is, in particular,
During the development of the frame, the developer is sprayed from above and below the piezoelectric substrate in a direction perpendicular to the upper surface of the piezoelectric substrate. As a result, the developer becomes a thin film on the piezoelectric substrate, swells and dissolves constantly in contact with the photosensitive resin film, and the development can be completed in a short time. Also, when the center of the injection of the developer is shifted from the center of the piezoelectric substrate,
Although a large amount of the photosensitive resin residue is generated in the central portion, by spraying the developer from the vertical direction, it becomes easy to aim at the center of the piezoelectric substrate, and the photosensitive resin residue can be reduced.

The invention described in claim 4 of the present invention particularly provides
When the lid is developed, the developer is sprayed from above and obliquely to the piezoelectric substrate. When the developer is sprayed from the vertical direction, the removed photosensitive resin falls between the frames and the piezoelectric substrate is removed. Adhesion to the surface increases the residue of the photosensitive resin. However, by injecting from an oblique direction, the removed photosensitive resin falls between the frames and flows at the same time as the injection pressure, so that the residue of the photosensitive resin can be reduced.

[0017] The invention described in claim 5 of the present invention particularly provides
The method includes a step of holding the piezoelectric substrate in oxygen plasma for a predetermined time after the frame is formed and before the lid is formed, and the frame is formed to incinerate and remove the organic components of the small photosensitive resin residue on the piezoelectric substrate. With this, when bumps or the like for making electrical connection with an external circuit are formed on the connection electrode, a bump having sufficient connection strength with the connection electrode can be formed. Also IDT
When a residue of the photosensitive resin is present on the surface, the propagation loss of the surface acoustic wave increases. However, since the surface acoustic wave is removed by oxygen plasma, the propagation loss can be prevented.

[0018] The invention described in claim 6 of the present invention is, in particular,
The method includes a step of holding the piezoelectric substrate in oxygen plasma for a predetermined time after the lid is formed and before the cover is formed. By forming the lid, the organic component of the small photosensitive resin residue on the piezoelectric substrate is ashed and removed. With this, when bumps or the like for making electrical connection with an external circuit are formed on the connection electrode, a bump having sufficient connection strength with the connection electrode can be formed.

The invention described in claim 7 of the present invention particularly provides
After the lid is formed, the piezoelectric substrate is heat-treated and then held in oxygen plasma, and after the heat treatment, the lid is completely hardened and the strength is improved, and the pressure is reduced in the oxygen plasma holding step and returned to normal pressure during removal. The deformation of the lid body, especially the contact with the IDT on the piezoelectric substrate, can be prevented.

The invention according to claim 8 of the present invention particularly provides
After the lid is formed, the piezoelectric substrate is irradiated with ultraviolet rays before the heat treatment.
Can be suppressed.

The invention as defined in claim 9 of the present invention particularly provides
After the lid is formed and the piezoelectric substrate is held in the oxygen plasma for a predetermined time, the pressure is gradually increased to normal pressure, and a sudden pressure difference is generated between the inside and outside of the space formed by the piezoelectric substrate, the frame, and the lid. Is generated, and contact of the lid with the IDT can be suppressed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Hereinafter, the first embodiment of the present invention will be described, particularly the inventions described in claims 1 to 9.

FIG. 1 shows an SA according to the first embodiment of the present invention.
It is sectional drawing of a W device.

In the figure, 11 is a piezoelectric substrate made of lithium niobate, lithium tantalate, or the like, 12 is an aluminum or aluminum alloy IDT provided on the piezoelectric substrate 11, 13 is a connection electrode connected to the IDT 12,
Reference numeral 14 denotes a frame provided around the outer peripheral portion of the IDT 12 on the piezoelectric substrate 11 using a photosensitive resin film containing a photosensitive monomer (acrylic monomer or the like) as a main component;
Reference numeral 15 denotes a lid provided using the same photosensitive resin film so as to cover the space above the frame 14 and the portion (IDT 12) where the surface acoustic wave propagates, and 16 denotes the piezoelectric substrate 11, IDT1.
2. SAW provided with connection electrode 13, frame 14, and lid 15
Element 17 is a bump formed of gold or the like for connecting the connection electrode 13 to an external electrode of the substrate, and 18 is a SAW element 16
, A sealing substrate for mounting the SAW device, and 20 an external electrode formed on the circuit board 19.

A method for manufacturing the SAW device configured as described above will be described with reference to the drawings.

FIG. 2 shows SA in Embodiment 1 of the present invention.
It is a manufacturing process figure of a W device.

FIG. 3 is a side view for explaining a step of forming the frame body 14 according to the first embodiment of the present invention, FIG. 4 is a top view of the same, and FIG. FIG. 6 is a side view for explaining the forming process, FIG.
FIG. 6 is an enlarged side view of a main part of FIG. 5.

In the drawing, reference numeral 21 denotes a table, 11 denotes a piezoelectric substrate mounted on the table 21, 22 denotes a straight nozzle,
23 is a developer, 24 is an exposed portion of a photosensitive resin film, 2
Reference numeral 5 denotes the unexposed portion.

First, as shown at 100 in FIG. 2, at least an IDT 12 and a connection electrode 13 connected thereto are formed on the surface of a large-sized piezoelectric substrate 11 using aluminum or an aluminum alloy.

Next, as shown by 101a in FIG. 2, a photosensitive resin film is laminated on the entire surface of the portion of the piezoelectric substrate 11 which will become the SAW element 16. The photosensitive resin film is mainly composed of a photosensitive monomer (such as an acrylic monomer), a thermosetting monomer (such as an epoxy resin) for improving heat resistance, and a filler (for example, talc or aluminum hydroxide) for improving strength. Etc.).

Next, as shown by 101b and 101c in FIG. 2, the photosensitive resin film is exposed and developed using a predetermined pattern mask.

The developing step will be described in detail as shown at 101c in FIG. As shown in FIGS. 3 and 4, the back surface of the piezoelectric substrate 11 is fixed on the table 21 by vacuum suction or the like.
The straight nozzle 2 above while rotating the table 21
From 2, the developer 23 is ejected vertically for a predetermined time while aiming at the center of the piezoelectric substrate 11. The unnecessary portion of the photosensitive resin film swells and dissolves when the developer 23 comes into contact, and is removed by the jet pressure. The number of rotations of the table 21 during development is preferably as fast as possible to remove unnecessary developer 23 and swelled and dissolved photosensitive resin by centrifugal force.
000r / min is desirable. Similarly, it is desirable that the liquid pressure of the injection be 2 × 10 ⁵ Pa or more.

After the development, as shown at 101 in FIG. 2, the piezoelectric substrate 11 is washed with water, drained and dried to obtain a frame 14.

Next, as shown at 102 in FIG.
If there is a residue of the photosensitive resin on the surface of the piezoelectric substrate 11 after the formation, the following steps may be performed. That is, the piezoelectric substrate 11
Is kept in oxygen plasma for a certain period of time, that is, oxygen plasma ashing is performed to ash the residue of the photosensitive resin. The components of the photosensitive resin are mainly composed of carbon and hydrogen, except for the filler, which is an inorganic substance, and are converted to carbon dioxide and water vapor by the reaction with oxygen, and are ashed and removed. At this time, the oxygen plasma was maintained in an oxygen plasma pressure of about 133 Pa and a high frequency output of 5
This is performed at 0 to 200 W for about 2 to 10 minutes. If the high-frequency output is increased and the holding time is increased, the surface of the frame 14 itself is considerably ashed, and the adhesion to the lid 15 to be formed next is deteriorated. Further, if the high-frequency output is weak and the holding time is short, the ashing of the residue becomes insufficient. In addition, although the filler which is an inorganic substance will remain, the amount originally contained in the photosensitive resin film is small, and even if it remains fine, it does not adversely affect the formation of the bump which is a post-process even if it remains fine. .

Next, as shown at 103a in FIG.
A photosensitive resin film serving as a lid 15 is adhered onto the cover 4. At this time, as shown in FIG. 11, the photosensitive resin film adheres only to the upper surface of the frame 14, and the piezoelectric substrate 11 and the IDT
12. Avoid contact with the connection electrode 13.

Thereafter, exposure and development are carried out in the same manner as in the formation of the frame 14 as shown at 103b in FIG. 2 and development is carried out as shown at 103c in FIG.
Change the position of 2. In other words, for the development when forming the frame 14, the linear nozzle 22 is installed at a position where the developer 23 is jetted from the vertical direction to the piezoelectric substrate 11 as shown in FIG. When developing, as shown in FIG. 5, the linear nozzle 22 is installed so as to be inclined with respect to the piezoelectric substrate 11, and the center of the piezoelectric substrate 11 is aimed obliquely from the oblique direction. The liquid 23 is injected. As shown in FIG. 7, the photosensitive resin of the unexposed portion 25 to be removed falls between the frames 14 due to the oblique injection, and is removed by being washed away by the developing solution 23 without adhering to the piezoelectric substrate 11. Therefore, the residue of the photosensitive resin can be reduced.

In this case, it is desirable that the straight nozzle 22 is inclined at 5 to 45 °, preferably about 20 ° with respect to the vertical plane of the piezoelectric substrate 11. If the inclination angle of the straight nozzle 22 is small, the effect of removing the photosensitive resin dropped between the frame bodies 14 is small. If the inclination angle is too large, it is difficult to aim the central portion of the piezoelectric substrate 11 to eject the developer 23. Becomes
Conversely, a photosensitive resin residue is likely to be generated at the center of the piezoelectric substrate 11. Also, at this time, similarly to the development of the frame 14, the rotation of the table 21 is 100 to 1000 r / min.
It is desirable that the hydraulic pressure of the injection be 2 × 10 ⁵ Pa or more.

After the development, as shown at 103 in FIG. 2, the piezoelectric substrate 11 is washed with water, drained, and dried to obtain the lid 15.

Next, as shown at 104 in FIG. 2, the piezoelectric substrate 11 is irradiated with ultraviolet rays to cure the frame 14 and the lid 15, and then, as shown at 105 in FIG.
Heat treatment for 0 minute to 2 hours.

Further, when a photosensitive resin residue is generated in the step of forming the lid 15, the photosensitive resin residue is left in an oxygen plasma for a certain period of time as in the case of the frame 14, and the photosensitive resin residue is ashed.
The oxygen plasma ashing indicated by 106 is performed. The holding in the oxygen plasma is also performed at an oxygen gas pressure of about 133 Pa and a high frequency output of 50 to 200 W for about 2 to 10 minutes for the above-described reason.

The SAW element 16 is obtained through the above steps.

Next, as shown at 107 in FIG. 2, a bump 17 is formed on the connection electrode 13 of the SAW element 16, and the SA is connected to the external electrode 20 provided on the circuit board 19 via the bump 17.
The bump is bonded to the external electrode 20 so that the W element 16 is electrically connected, and the process is performed as shown by 108 in FIG. At this time, since the height of the bumps 17 is higher than the height of the frame 14 and the height of the lid 15 combined, the height of the
There is a space between.

Next, as shown in FIG.
The entire surface on which the electrodes of the W element 16 are formed and the outer periphery of the bump 17 are covered with a sealing resin 18 such as an epoxy resin, and the resin is sealed as shown at 109 in FIG. 2 to obtain a SAW device.

The characteristics of the SAW device configured as described above will be described.

FIG. 8 is a side view for explaining a step of forming a frame 14 in another embodiment of the present invention, FIG. 9 is a top view of the same, and FIG. 10 is a view for explaining a step of forming a frame in a comparative example. FIG. 11 is a top view of FIG.
The same components as those described above are denoted by the same reference numerals, and description thereof is omitted.
In the figure, 31 is a fan-shaped nozzle, and 32 is a full-cone nozzle.

If the frame 14 and the lid 15 are significantly deformed,
It is difficult to secure the excitation space for surface acoustic waves.
There is a possibility that the characteristics of the device may be degraded. Frame 1
As described above, the deformation of the cover 4 and the cover 15 is also caused by a long development time.

Therefore, a comparison of the developing time between the developing method (hereinafter, referred to as a table rotation method) performed in the first embodiment and the conventional developing method, and a nozzle having a different shape in the developing method performed in the first embodiment. Was used to compare the development time.

The results are shown in (Table 1).

[0049]

[Table 1]

As can be seen from Table 1, when the development is performed by the conventional developing method, that is, by the immersion vertical swinging method and the upward jetting method, in any case of the frame 14 and the lid 15, The table rotation method as described in the first embodiment has a shorter development time.

Also, in the table rotation method, as shown in FIGS.
As compared with the case of using No. 2, the development time is the shortest when the straight nozzle 22 is used as shown in the first embodiment, and deformation and swelling hardly occur.

However, even when the fan-shaped nozzle 31 is used, no deformation of the frame 14 and the lid 15 is required, and the same applies to the case where the fan-shaped nozzle 31 is used instead of the straight nozzle 22 in the first embodiment. It can be seen that the effect can be obtained.

The linear nozzle 22 and the fan-shaped nozzle 31 have a higher injection pressure of the developing solution than other nozzles such as the conical nozzle 32, and the strong injection pressure sufficiently removes the swelled and dissolved photosensitive resin. Can be. Further, since the ejection area is small, the amount of the developer deposited on the piezoelectric substrate 11 is small, and the ejection pressure is sufficiently applied to the piezoelectric substrate 11, whereby the removal by the ejection can be effectively performed.

In the case of the conventional immersion vertical swinging method or the upward spraying method, there is no effect of removing the piezoelectric substrate by the rotational centrifugal force, and the removing effect by the spray pressure is weak. Deformation and swelling occur. Especially the frame 14
And it becomes remarkable when the lid 15 has a fine shape.

Further, in the conventional general developing method, the residue of the photosensitive resin is large, and the connection strength between the bump 17 and the connection electrode 13 is weak and the dispersion is large. However, according to the developing method of the first embodiment, the residue of the photosensitive resin is very small as compared with the conventional method.

As described above, in the first embodiment,
At the time of developing at least one of the frame 14 and the lid 15 (FIG. 2)
101c, 103c), by spraying the developer while rotating the piezoelectric substrate 11, swelling with the developer,
The dissolved photosensitive resin is removed together with the developer by centrifugal force due to the rotation of the piezoelectric substrate 11, and the swelling, dissolving, and removing are constantly repeated, so that the development is completed in a short time, and the deformation of the frame 14 or the cover 15 Can be suppressed. Especially swelling,
The effect is remarkable in the lid 15 that is easily deformed.

Further, by injecting the developing solution using the linear nozzle 22 or the fan-shaped nozzle 31, the swelling and dissolved photosensitive resin can be sufficiently removed by the strong injection pressure,
Further, since the injection area is small, a small amount of the developer is deposited on the piezoelectric substrate 11, and the injection pressure is sufficiently applied to the piezoelectric substrate 11, so that the development time is shortened and the residue of the photosensitive resin can be reduced.

Further, when the frame 14 is developed (see FIG.
1c) The spraying of the developing solution is performed vertically upward with respect to the piezoelectric substrate 11, and the developing solution becomes a thin film on the piezoelectric substrate 11 after an appropriate spraying pressure applied to the piezoelectric substrate 11 is secured. In contact with the photosensitive resin film, swelling and dissolution proceed quickly, and development can be completed in a short time. In addition, since the developer is easily sprayed on the center of the piezoelectric substrate, the residue of the photosensitive resin can be reduced.

Further, at the time of developing the lid 15 (103 c in FIG. 2), the photosensitive resin removed by the spraying of the developing solution from above and obliquely to the piezoelectric substrate 11 is held between the frame 14. Since the resin is dropped and jetted at the same time as the jetting pressure, residues of the photosensitive resin can be reduced.

In addition, after the frame 14 is formed and before the lid 15 is formed, the piezoelectric substrate 11 is held in oxygen plasma for a predetermined time (102 in FIG. 2), so that the frame 14 is formed. The organic component of the residue of the photosensitive resin existing in the substrate is ashed and removed, and the bump 17 having sufficient connection strength with the connection electrode 13 can be formed. Further, by removing the residue of the photosensitive resin on the IDT 12, an increase in propagation loss can be prevented.

Further, after the lid 15 is formed and before the bump 17 is formed (106 in FIG. 2), the piezoelectric substrate 11 is exposed to oxygen plasma.
Is held for a predetermined time, the organic matter of the residue of the photosensitive resin present on the piezoelectric substrate 11 is ashed and removed by forming the lid 15, and the bump 17 having sufficient connection strength with the connection electrode 13 is formed. can do.

After the lid 15 is formed, the piezoelectric substrate 11 is subjected to a heat treatment (105 in FIG. 2) to complete the curing of the lid 15 and to improve the strength, and a step of holding in oxygen plasma (106 in FIG. 2). In the cover 15, especially the ID on the piezoelectric substrate 11.
Contact with T12 can be prevented.

Further, after the lid 15 is formed, the piezoelectric substrate 11 is irradiated with ultraviolet rays (104 in FIG. 2), whereby the lid 1
5 is hardened and softened during the heat treatment, and the ID on the piezoelectric substrate 11 is
Contact with T12 can be suppressed.

Further, after the piezoelectric substrate 11 is held in the oxygen plasma for a predetermined time (106 in FIG. 2), the pressure is gradually increased to normal pressure, and the piezoelectric substrate 11, the frame 14 and the cover 15 It is possible to suppress a sudden pressure difference between the inside and outside of the formed space and the contact of the lid 15 with the IDT 12.

In the first embodiment, the SAW
After mounting the element 16 on the circuit board 19 via the bump 17,
Although the space between the SAW element 16 and the circuit board 19 and the outer periphery of the bump 17 are covered with the sealing resin 18, the sealing resin 18 may be provided so as to cover not only this part but also the entire SAW element 16. Similar effects can be obtained by providing a metal cap or the like that covers the entire SAW element 16 instead of the sealing resin 18. Further, it may be sealed in a container-shaped package instead of the sealing resin 18.

(Embodiment 2) Hereinafter, the second embodiment of the present invention will be described in particular with reference to claims 1 to 9. FIG. 12 is a sectional view of the SAW device according to the second embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

In FIG. 12, reference numeral 40 denotes a resin such as silicon for fixing the SAW element 16 on the circuit board 19;
Reference numeral 1 denotes a wire such as gold or aluminum for electrically connecting the connection electrode 13 and the external electrode 20.

The difference from the first embodiment is that the SAW element 1
6 is performed using the wires 41 instead of using the bumps, and the mounting direction of the SAW element 16 is upside down. Therefore, the SAW element 16 and the entire wire are sealed with the sealing resin 18. The point to be covered.

A method for manufacturing the SAW device configured as described above will be described.

First, similarly to the first embodiment, the frame 14
And a SAW element 16 having a lid 15 (FIG. 2).
100-106).

Next, the SAW is formed on the circuit board 19 with the resin 40.
The element 16 is fixed. Next, the connection electrode 13 and the external electrode 20 are connected by the wire 41. Then, the SAW element 1
6 and the entire wire 41 are covered with the circuit board 19.
The SAW device is obtained by providing the sealing resin 18 thereon.

The SAW device according to the second embodiment also has the same effect as the first embodiment since the frame 14 and the lid 15 are formed in the same manner as in the first embodiment.

Also in the second embodiment, as in the first embodiment, since the frame 14 and the lid 15 are formed, the existing photosensitive resin residue on the piezoelectric substrate 11 is removed by oxygen plasma. Thus, the electrical connection between the connection electrode 13 and the wire 41 can be reliably established.

Further, in the second embodiment, the outer periphery of the SAW element 16 is covered with the sealing resin 18, but a cover such as a metal cap may be provided on the circuit board 19 instead of the sealing resin 18. . Of course, it may be enclosed in a container-like package.

In the first and second embodiments, a photosensitive monomer (acrylic monomer) is used as the main component of the photosensitive resin film, and a thermosetting resin (epoxy resin) for providing heat resistance is used as an auxiliary component. Although a filler (talc, aluminum hydroxide, etc.) for improving strength was added, if heat resistance and strength could be secured,
A material not containing a thermosetting resin or a filler may be used.

[0076]

As described above, according to the present invention, at least one of a frame and a lid formed by using a photosensitive resin is developed by spraying a developing solution while rotating a piezoelectric substrate. Since the swelling, dissolution, and removal of the photosensitive resin are effectively performed and development is completed in a short time, there is no deformation of the pattern, particularly the deformation of the lid, and the residue of the photosensitive resin is very small. Furthermore, since the residue of the photosensitive resin is also removed by the oxygen plasma, a SAW device having a stable connection strength such as bump formation and wire bonding can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a SAW device according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a SAW device according to the first embodiment of the present invention.

FIG. 3 is a side view for explaining a developing step in the first and second embodiments of the present invention.

FIG. 4 is a top view for explaining a developing step according to the first and second embodiments of the present invention.

FIG. 5 is a side view for explaining a developing step in the first and second embodiments of the present invention.

FIG. 6 is a top view for explaining a developing step according to the first and second embodiments of the present invention.

FIG. 7 is an enlarged side view of a main part of FIG. 5;

FIG. 8 is a side view for explaining a developing step in another embodiment of the present invention.

FIG. 9 is a top view for explaining a developing step in another embodiment of the present invention.

FIG. 10 is a side view for explaining a developing step in a comparative example.

FIG. 11 is a top view for explaining a developing step in a comparative example.

FIG. 12 is a sectional view of a SAW device according to a second embodiment of the present invention.

FIG. 13 is a sectional view of a conventional SAW device.

FIG. 14 is a cross-sectional view for explaining a general developing process.

FIG. 15 is a side view for explaining a general developing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Piezoelectric substrate 12 IDT 13 Connection electrode 14 Frame 15 Lid 16 SAW element 17 Bump 18 Sealing resin 19 Circuit board 20 External electrode 21 Table 22 Linear nozzle 23 Developing liquid 24 Exposed part 25 Unexposed part 31 Sector nozzle 32 Filled cone Nozzle 40 Resin 41 Wire

Claims (9)

[Claims] A first step of forming an interdigital transducer and a connection electrode connected to the interdigital transducer on a surface of the piezoelectric substrate; and a step of bringing a photosensitive resin film into close contact with the surface of the piezoelectric substrate for a predetermined time. A second step of forming a frame surrounding the outer periphery of the interdigital transducer by exposing and developing the pattern, and then exposing the photosensitive resin film to the surface of the piezoelectric substrate again in a predetermined pattern, A third step of forming a lid on the frame by developing and covering the interdigital transducer with the frame and the lid, and then a cover for covering the outer periphery of the frame and the lid. And providing at least one of the developing steps in the second and third steps by using the piezoelectric substrate. A method for manufacturing a SAW device by spraying a developer while rotating the SAW device. 2. The method for manufacturing a SAW device according to claim 1, wherein the injection of the developing solution is performed using a linear nozzle or a fan-shaped nozzle. 3. The method according to claim 1, wherein in the second step, the developer is injected from a direction perpendicular to the piezoelectric substrate from above.
Manufacturing method of AW device. 4. The method according to claim 1, wherein, in the third step, the developer is injected from an obliquely upward direction with respect to the piezoelectric substrate.
Manufacturing method of AW device. 5. The method for manufacturing a SAW device according to claim 1, further comprising a step of holding the piezoelectric substrate in oxygen plasma for a predetermined time after the second step and before the third step. 6. The method for manufacturing a SAW device according to claim 1, further comprising a step of holding the piezoelectric substrate in oxygen plasma for a predetermined time after the third step and before the fourth step. 7. The method for manufacturing a SAW device according to claim 6, wherein the piezoelectric substrate is held in oxygen plasma after the heat treatment. 8. The method for manufacturing a SAW device according to claim 7, wherein ultraviolet rays are irradiated to the piezoelectric substrate before the heat treatment. 9. The method for manufacturing a SAW device according to claim 6, wherein the pressure is gradually reduced after maintaining in oxygen plasma for a predetermined time.