CN114024520B - Double-layer film coating process for acoustic device - Google Patents
Double-layer film coating process for acoustic device Download PDFInfo
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- CN114024520B CN114024520B CN202111293530.6A CN202111293530A CN114024520B CN 114024520 B CN114024520 B CN 114024520B CN 202111293530 A CN202111293530 A CN 202111293530A CN 114024520 B CN114024520 B CN 114024520B
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- 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
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Abstract
The invention provides a double-layer film coating process of an acoustic device, which comprises a circuit assembly, a film coating assembly and a film coating assembly, wherein the circuit assembly comprises a circuit substrate, a first surface and a second surface which are opposite to each other are arranged on the circuit substrate, the first surface is provided with the acoustic device, and the acoustic device and the first surface are enclosed to form a hollow structure; providing a resin sheet assembly having a first layer of resin and a second layer of resin bonded between the first and second resin layers; disposing the resin sheet assembly on the circuit assembly with the first layer of resin facing in a direction of the acoustic device and the second layer of resin facing away from the acoustic device; the resin sheet member is heated and pressed toward the circuit member and then cured so that the resin sheet member covers the outer surface of the acoustic device and an area of the acoustic device outside the projected area of the first surface. The double-layer film covering process has the advantages that the sealing performance is obviously improved, the connection reliability of circuit components such as SAW (surface acoustic wave) and other acoustic devices and a circuit substrate is improved, and meanwhile, the yield and the production efficiency are improved.
Description
Technical Field
The invention relates to the technical field of acoustic devices, in particular to a double-layer film coating process of an acoustic device.
Background
In recent years, electronic components such as functional elements are widely used in various electronic devices including mobile phones, in which a chip such as a functional element is mounted on a wiring board by bumps and the chip and the wiring board are sealed while being kept hollow. Typically, this includes Surface Acoustic Wave (SAW) filters, surface acoustic wave sensors, duplexers, multiplexers, crystal oscillators, piezoelectric oscillators, and the like. In such an electronic component, the upper surface of the functional element is not sealed with resin, for example, the surface of the SAW filter has IDT electrodes, the surface of the IDT electrodes is very sensitive, and if a sealing resin or a substrate surface is in contact with the IDT electrodes, the SAW filter cannot operate normally, and resin sealing is required while keeping the surface of the IDT electrodes hollow, and thus flip chip packaging technology is the mainstream packaging technology for electronic components including SAW filters.
On the other hand, in the case of actually using the mounting structure, the thermal expansion and contraction of the sealing material may be repeated in accordance with a temperature change due to an external environment, self-heating, or the like. At this time, the solder bumps are also repeatedly stretched in the direction in which the sealing material expands and/or contracts, the circuit component adhering to the sealing material is stretched in the direction in which the sealing material expands, and the circuit component is stretched in the direction in which the sealing material contracts when the sealing material is cooled. Since the circuit member itself is not easily deformed, a tensile stress applied to the circuit member acts on the protrusion disposed in the internal space, so that the protrusion may be peeled off from the circuit substrate, and thus the circuit member such as an acoustic device such as SAW is peeled off from the circuit substrate, resulting in a failure of the acoustic device.
Disclosure of Invention
In order to solve the related problems in the prior art, the invention provides a double-layer film coating process of an acoustic device, which is characterized by comprising the following steps of: s1: providing a circuit assembly, which comprises a circuit substrate and a circuit substrate, wherein the circuit substrate is provided with a first surface and a second surface which are opposite to each other, the first surface of the circuit substrate is provided with an acoustic device, and the acoustic device and the first surface of the circuit substrate enclose a hollow structure; s2: providing a resin sheet assembly having a first layer of resin and a second layer of resin, the first and second layers of resin being bonded to one another to form the resin sheet assembly; s3: disposing the resin sheet assembly on the circuit assembly with the first layer of resin facing in a direction of the acoustic device and the second layer of resin facing away from the acoustic device; s4: the resin sheet member is heated and pressed toward the circuit member and then cured so that the resin sheet member covers the outer surface of the acoustic device and a region of the acoustic device outside a projected region of the first surface of the circuit substrate.
Further, the layer thickness of the second layer of resin is greater than the layer thickness of the first layer of resin.
Further, the layer thickness of the first layer of resin is greater than the layer thickness of the second layer of resin.
Wherein the second layer of resin is of a single-layer structure.
Wherein the second layer of resin may be a multilayer structure.
Further, the second layer of resin is an epoxy resin film containing a thermally conductive filler and a shielding filler.
Further, the first layer of resin is a plastic resin, and the second layer of resin is a sealing resin.
Or the first layer of resin is plastic resin, and the second layer of resin is light-cured resin.
Further, the plastic resin of the first layer resin satisfies, at the heating temperature of step S4: the viscosity is 50-150kPas.
Further, the plastic resin of the first layer resin satisfies, at the heating temperature of step S4: modulus of elasticity in shear of 1X 10 5 Pa or above.
Specifically, the thickness of the plastic resin of the first layer of resin is between 10um and 100 um.
Wherein, in step S4, the heating temperature is above 40 ℃ and below 180 ℃.
Further, the sealing resin of the second layer resin has a shear modulus of elasticity of 1X 10 5 Pa or above.
Still further, the thermal conductivity in the thickness direction of the second layer resin after curing is smaller than the thermal conductivity in the length direction.
Still further, the acoustic device is plural, and the first layer resin is divided into a plurality of sub-sheets corresponding to the plural acoustic devices.
The invention also provides an acoustic device package prepared by the acoustic device double-layer film covering process, wherein the acoustic device comprises the piezoelectric oxide single crystal substrate.
According to the acoustic device double-layer film covering process and the acoustic device package prepared by the process, the heat resistance and the moisture resistance are high, the sealing performance is reliable, water vapor, dust and the like can be better prevented from entering the inner space of the package body, and therefore the generation of bulge cracks can be better avoided when the inner space expands, and therefore the connection reliability of circuit components such as SAW and other acoustic devices and a circuit substrate can be improved, and the working stability and reliability of a communication device can be guaranteed. Meanwhile, the invention improves the process, and the resin sheet component is encapsulated by one-step process, thereby simplifying the process operation flow and improving the yield and the production efficiency.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a flowchart of a double-layer coating process of an acoustic device according to an embodiment of the invention.
Fig. 2 (a) - (c) are explanatory views schematically showing a manufacturing method according to an embodiment of the present invention by a cross section of a mounting member or a mounting structure.
Fig. 3 (a) to (c) are explanatory views schematically showing a manufacturing method according to another embodiment of the present invention by a cross section of a mounting member or a mounting structure.
Fig. 4 (a) to (c) are explanatory views schematically showing a manufacturing method according to still another embodiment of the present invention by a cross section of a mounting member or a mounting structure.
Reference numerals are as follows:
1. 101, 102-Circuit Board
2. 201, 21, 22-acoustic device
3. 301-bump
4. 40-resin sheet assembly
41. 401 first layer resin
410. 411-sub-tablet
42. 402, 420-second layer resin
403-inner layer resin
404-outer layer resin
11-first surface
12-second surface
13-hollow structure
Detailed Description
So that the manner in which the above recited objects, features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
Example one
As shown in fig. 1, the present embodiment provides a double-layer coating process for an acoustic device, which is characterized by comprising the following steps: s1: providing a circuit assembly, which comprises a circuit substrate and a circuit substrate, wherein the circuit substrate is provided with a first surface and a second surface which are opposite to each other, the first surface of the circuit substrate is provided with an acoustic device, and the acoustic device and the first surface of the circuit substrate enclose a hollow structure; s2: providing a resin sheet assembly having a first layer of resin and a second layer of resin bonded together to form the resin sheet assembly; s3: disposing the resin sheet assembly on the circuit assembly with the first layer of resin facing in a direction of the acoustic device and the second layer of resin facing away from the acoustic device; s4: the resin sheet assembly is heated and pressed toward the direction of the circuit assembly and then cured so that the resin sheet assembly covers the outer surface of the acoustic device and a region of the acoustic device outside a projected region of the first surface of the circuit substrate. The acoustic device may be SAW, XBAR, or the like, which is packaged in a flip chip package manner, and the face having the IDT electrode is disposed in a gap formed between the acoustic device and the first surface of the circuit substrate, thereby preventing a sealing material such as resin or the like or a substrate face from contacting the IDT electrode, and further preventing the sensitive IDT electrode from being affected. Wherein the circuit substrate is a commonly used circuit board such as a PCB or other type of multi-layer wiring circuit board, but the invention is not limited thereto.
The invention improves the process, encapsulates the resin sheet component by one process, simplifies the process operation flow and improves the yield and the production efficiency. Specifically, when the process is performed, the thickness of the resin sheet assembly may be adjusted according to the size of the acoustic device, the operating characteristics, and the material and performance of the resin sheet, for example, the thickness of the first layer of resin is between 10um and 100um, the thickness of the second layer of resin is the same as that of the first layer of resin, or is greater than that of the first layer of resin, or the thickness of the second layer of resin is smaller than that of the first layer of resin, preferably greater than that of the first layer of resin, and may be set to be between 100um and 400um, for example. In this embodiment, the thickness of the first layer of resin is 60-80um, and the thickness of the second layer of resin is 350-370um. Particularly, in the process implementation, the thickness of the two resin sheets may be adjusted according to the size of the acoustic device, the operating characteristics, and the material and performance of the resin sheets, but the present invention is not limited thereto.
Wherein in step S4, the heating temperature is 40 ℃ to 180 ℃, preferably 40 to 100 ℃. At the preferred temperature, the applied pressure is 0.2MPa or more, preferably 0.2 to 0.8MPa, and at this preferred temperature, the corresponding pressing time is set to 30 to 100 seconds, preferably 30 to 70 seconds, and the specific time is inversely proportional to the magnitude of the applied pressure, so as to obtain a more stable bonding effect, in this embodiment, at a lower pressure of 0.2MPa, the pressing time may be relatively longer, set to 70 seconds; the vacuum degree is less than 0.5hPa, and the vacuum time is more than 10 seconds, preferably 10 to 50 seconds. The heating temperature can be adjusted according to the difference of the two layers of resin materials. For example, in the present embodiment, the first resin sheet is polycarbonate, and the heating temperature may be set to 80 to 120 ℃. And may be polyisobutylene, and the heating temperature may be set to 90-130 deg.c. The second resin sheet is a copolymer resin, for example, an α -olefin copolymer, and the heating temperature is 80 ℃. The resin sheet is then cured to seal the acoustic device. The acoustic device package structure prepared according to the double-layer film coating process in this embodiment has high heat resistance and moisture resistance, and reliable sealing performance. After the normal temperature side leakage inspection, the acoustic device packaging structure was placed in an environment of 85% humidity and 85 ℃ for 240 hours continuously, and the test passing rate was 10ppm. Compared with 500-1000ppm of the conventional packaging process, the yield improvement effect is remarkable. Furthermore, the acoustic device can better avoid the expansion of the inner space caused by the water vapor and dust entering the hollow structure in the long-time work, thereby inhibiting the generation of the convex cracks and improving the connection reliability of the circuit component such as the acoustic device of SAW and the like and the circuit substrate.
Example two
As shown in fig. 2, this embodiment is to encapsulate the acoustic device according to the two-layer coating process of the acoustic device in the first embodiment. As shown in fig. 2 (a), a circuit assembly is provided, which includes a circuit substrate (1) having a first surface (11) and a second surface (12) which are opposite to each other, wherein the first surface (11) of the circuit substrate (1) is provided with an acoustic device (2), and the acoustic device (2) and the first surface (11) of the circuit substrate (1) enclose a hollow structure (13) through bumps (3); then as in fig. 2 (b), providing a resin sheet assembly (4) having a first layer of resin (41) and a second layer of resin (42), the first layer of resin (41) and the second layer of resin (42) being interlaminar bonded to form the resin sheet assembly (4); arranging the resin sheet assembly (4) on the circuit assembly with the first layer of resin (41) facing in a direction of the acoustic device (2), the second layer of resin (42) facing away from the acoustic device; as in fig. 2 (c), the resin sheet member (4) is heated and pressed toward the circuit member and then cured so that the resin sheet member (4) covers the outer surface of the acoustic device (2) and the area of the acoustic device (2) outside the projected area of the first surface (11) of the circuit substrate (1).
In the embodiment, the first layer of resin (41) and the second layer of resin (42) are combined and bonded together, and the resin sheet assembly is encapsulated by one process, so that the process operation flow can be simplified, and the yield and the production efficiency can be improved. The first layer resin (41) is plastic resin composed of high molecular material, such as epoxy resin, phenolic resin, plastic resin, saturated or unsaturated resin, etc. In this example, a plastic resin excellent in heat resistance, thermal stability, low water absorption, surface hardness and mechanical strength was used as an example, and the components included polycarbonate, a resin mixture containing an acrylate-based rubber, polyisobutylene and polyphenyleneEthylene and polybutadiene, etc., having a thickness of between 10um and 100um, for example 50mm in this example, with a filler content of 81% by weight, with a filler size of 6um on average and 32um at maximum. The plastic resin has a viscosity of 50-150kPas, typically 90-110kPas, at a heating temperature of 40 ℃ or higher and 180 ℃ or lower. At the same time, the first layer resin (41) has a dielectric tangent tan delta of 0.2 or less, preferably 0.05, and a shear modulus of elasticity of 1X 10 at a heating temperature of 40 ℃ to 180 ℃ inclusive 5 Pa or above. The first layer resin (41) contains 20ppm or less of ionic impurities (Na, K, cl), and therefore, the material has a specific dielectric constant of 1 to 9 and a small dielectric tangent tan delta, preferably a dielectric constant of 3.7 and a dielectric tangent of 0.05, at a frequency of 1 MHz. The plastic resin has excellent resistance to thermal cycling, is well suited for sealing semiconductor elements, has a glass transition temperature (Tg) as determined by thermomechanical analysis (TMA) of greater than 30 ℃, preferably greater than 100 ℃, and typically 135-140 ℃, and has a coefficient of linear expansion (CTE) of 100ppm/K or less at that temperature, e.g., a CTE typically between 20-30ppm/K below Tg and a CTE typically between 50-60ppm/K above Tg. The resin has a thermal decomposition temperature of 300 ℃ or more, which is 385 ℃ in this example. In this example, the plastic resin used was measured to have a storage modulus at 25 ℃ of 8GPa and a storage modulus at 260 ℃ of 0.38GPa.
The second resin layer (42) is a sealing resin, and in this example, contains an ethylene/unsaturated ester copolymer and an acid-modified styrene copolymer. The thickness of the second layer of resin (42) is greater than the thickness of the first layer of resin (41) and may be less than or equal to the thickness of the first layer of resin (41), and the present embodiment illustrates that the thickness of the second layer of resin (42) is greater than the thickness of the first layer of resin (41) and may be set between 100-400um, and the present embodiment sets the thickness to 210um-230um, the filler content is 85%wt, and the filler size is on average 6um, and at most 32um. The sealing resin has a viscosity of 60 to 100kPas, typically 60 to 80kPas, at a heating temperature of 40 ℃ or higher and 180 ℃ or lower. A dielectric tangent tan delta of 0.3 to 0.9, and a shear modulus of 1X 10 4 Pa or above. The sealing resin is excellent inIs well suited for sealing semiconductor elements, has a glass transition temperature (Tg) as determined by thermomechanical analysis (TMA) of more than 30 ℃, typically 59 ℃, and a coefficient of linear expansion (CTE) of 100ppm/K or less at that temperature, e.g. a CTE of 20ppm/K or less below Tg and a CTE between 40 and 60ppm/K above Tg. In this example, the storage modulus of the sealing resin used was measured to be 12GPa at 25 ℃ and 0.11GPa at 260 ℃. The layer thickness of the second layer resin (42) can also be set to 150um-180um, with a filler content of 75% by weight, and a filler size of 6um on average, up to 30um. Another typical scheme value for the layer thickness of the second layer resin (42) is 360um-380um, with a filler content of 90% wt. The thermal conductivity of the second layer resin (42) in the thickness direction after curing is smaller than the thermal conductivity in the length direction. Specifically, in the process implementation, the thickness, heating time and temperature, and vacuum time and temperature of the two resin sheets may be adjusted according to the size of the acoustic device, the operating characteristics, and the material and performance of the resin sheets, but the present invention is not limited thereto. In addition, the second layer of resin can also be a light-cured resin, for example, a compound containing an epoxy group or a compound containing an oxetane ring, and the light-cured resin shows excellent adhesive characteristics when irradiated for a certain time at low temperature and under illumination such as ultraviolet light, which can also remarkably improve the sealing performance of the acoustic device packaging structure. Furthermore, the acoustic device can better avoid the expansion of the inner space caused by the water vapor and dust entering the hollow structure in the long-time operation, thereby inhibiting the generation of the convex cracks and improving the connection reliability of the circuit component such as the acoustic device of SAW and the like and the circuit substrate.
The resin sheet assembly (4) has a thermal conductivity in the range of 0.5 to 5W/mK, preferably 0.7 to 1.0W/mK. The acoustic device package structure prepared according to the double-layer film-coating process in the present embodiment has a high return resistance, and has high heat resistance and moisture resistance, with reliable sealing performance. After the normal temperature side leakage inspection, the acoustic device package structure was placed in an environment of 85% humidity and 85 ℃ for 240 hours continuously, and the pass rate was measured to be 10ppm. Compared with 500-1000ppm of the conventional packaging process, the yield improvement effect is remarkable.
EXAMPLE III
As shown in fig. 3, this embodiment also encapsulates the acoustic device according to the two-layer coating process of the acoustic device in the first embodiment, which is similar to the first embodiment but is obviously different from the second embodiment. As shown in fig. 3 (a), a circuit assembly is provided, which includes a circuit substrate (101) having a first surface and a second surface opposite to each other, wherein the first surface of the circuit substrate (101) is provided with an acoustic device (201), and the acoustic device (201) and the first surface of the circuit substrate (101) enclose a hollow structure through bumps (301); thereafter as shown in fig. 3 (b), providing a resin sheet assembly (40) having a first layer of resin (401) and a second layer of resin (402), the first layer of resin (401) and the second layer of resin (402) being interlaminar bonded to form the resin sheet assembly (40); arranging the resin sheet assembly (40) on the circuit assembly with the first layer of resin (401) facing in a direction towards the acoustic device (201), the second layer of resin (402) facing away from the acoustic device (201); as in fig. 3 (c), the resin sheet member (40) is heated and pressed toward the circuit member and then cured so that the resin sheet member (40) covers the outer surface of the acoustic device (201) and the area of the acoustic device (201) outside the projected area of the first surface (11) of the circuit substrate (101).
The embodiment is different from the second embodiment in that the second layer resin (42) in the resin sheet assembly (4) of the second embodiment has a single-layer structure, can be a homogeneous epoxy resin film containing a heat conductive filler and a shielding filler. In the present embodiment, the second layer of resin (402) in the resin sheet assembly (40) may be a multi-layer structure, for example, including an inner layer of resin (403) and an outer layer of resin (404), which mainly provide heat conduction and shielding functions, respectively, so that the acoustic device operates more stably and reliably.
Some materials and characteristics of the first layer of resin (401) and the second layer of resin (402) in the resin sheet assembly (40) are similar to those of embodiment two, and are not repeated here.
Example four
This embodiment is to package the acoustic device according to the double-layer film coating process of the acoustic device in the first embodiment, which is a further improvement of the packaging process in the second embodiment, as shown in fig. 4. In fig. 4 (a), a circuit assembly is provided, which includes a circuit substrate (102) having a first surface and a second surface opposite to each other, wherein the first surface of the circuit substrate (102) is provided with a plurality of acoustic devices (21, 22), and the plurality of acoustic devices (21, 22) and the first surface of the circuit substrate (102) enclose a hollow structure through bumps; thereafter as in fig. 4 (b), providing a resin sheet assembly having a first layer of resin and a second layer of resin (420), the first and second layers of resin (420) being interlaminar bonded to form the resin sheet assembly; arranging the resin sheet assembly on the plurality of circuit assemblies (21, 22) with the first layer of resin facing in a direction of the acoustic device (21, 22), the second layer of resin (420) facing away from the acoustic device; as in fig. 4 (c), the resin sheet assembly is heated and pressed toward the direction of the circuit assembly and then cured so that the resin sheet assembly covers the outer surfaces of the acoustic devices (21, 22) and the areas of the acoustic devices (21, 22) outside the projected area of the first surface of the circuit substrate (102).
The present embodiment is different from the second embodiment in that there may be one or more acoustic devices in the second embodiment, and there are more acoustic devices in the present embodiment. Therefore, in this embodiment, the first resin layer is divided into a plurality of sub-sheets (410, 411) corresponding to the plurality of acoustic devices (21, 22), and the plurality of sub-sheets (410, 411) of the first resin layer may be interlayer-bonded to the second resin layer (420) when the resin sheet assembly is prepared, or the first resin layer may be cut according to the size of the acoustic devices (21, 22) to be encapsulated after the entire first resin layer and the second resin layer (420) are interlayer-bonded, thereby forming a plurality of sub-sheets (410, 411) corresponding to the plurality of acoustic devices (21, 22). Thus, when the heating and pressing steps in step S4 are performed, the tensile force of the first layer resin during the bonding with the acoustic devices (21, 22) during the heating process is reduced, so that the probability of generating voids in the bonding surface due to the tensile force is further reduced, and the sealing performance is further improved. After the normal temperature side leakage inspection, the acoustic device package structure was placed in an environment of 85% humidity and 85 ℃ for 240 hours continuously, and the pass rate was measured to be 8ppm. Compared with the acoustic device packaged by adopting the process in the first embodiment, the sealing performance of the acoustic device is further improved, and compared with 500-1000ppm of the conventional packaging process, the yield is improved remarkably, so that the acoustic device can better avoid expansion of an inner space caused by water vapor and dust entering the hollow structure in long-time work, the generation of convex cracks is inhibited, and the connection reliability of circuit parts such as SAW and other acoustic devices and a circuit substrate is improved. Other materials and process parameters are similar to those in embodiment two, and are not described herein again.
EXAMPLE five
The present embodiment provides an acoustic device prepared by the double-layer coating process of the acoustic device according to the foregoing embodiment, including: the circuit board comprises a circuit substrate, a first electrode and a second electrode, wherein the circuit substrate is provided with a first surface and a second surface which are opposite to each other, the first surface of the circuit substrate is provided with an acoustic device, the acoustic device and the first surface of the circuit substrate enclose a hollow structure, and the acoustic device and a bump are accommodated in the hollow structure; bumps through which the acoustic device is disposed on the first surface of the circuit substrate; a resin sheet assembly having a first layer of resin and a second layer of resin bonded therebetween, covering an outer surface of the acoustic device and an area of the acoustic device outside a projected area of the first surface of the circuit substrate. Where the acoustic device comprises a piezoelectric oxide single crystal substrate, which may comprise any piezoelectric material useful for SAW devices, such as lithium tantalate or lithium niobate, for example, or other piezoelectric materials (e.g., alN and ZnO) are also possible, a temperature compensation layer may also be provided thereon to reduce the temperature coefficient of frequency, thereby improving the temperature stability of the acoustic device, while a high acoustic velocity layer or the like may also be provided to further suppress signals generated by spurious modes, and the thickness of the acoustic velocity layer may be optimized to produce the desired mode suppression.
In the present example, the resistivity of the piezoelectric oxide single crystal substrate in the thickness direction was adjusted to an appropriate range, for example, 1 × 1010-1 × 1012 Ω · cm by oxidation-reduction treatment in order to suppress the surface electrification of the piezoelectric oxide single crystal substrate. Specifically, the piezoelectric oxide single crystal substrate may be subjected to reduction treatment using a solid reducing agent at a temperature of curie temperature or lower; or performing heat treatment at a temperature of 350 deg.C or higher and Curie temperature or lower in a mixed gas atmosphere of an inert gas and a reducing gas under normal pressure, wherein the reducing gas may be hydrogen or carbon monoxide; the piezoelectric oxide single crystal substrate can also be produced by a uniform reduction process by exposing the substrate of the substrate to LiO vapor and applying a reduction voltage in the z-axis direction of the substrate.
According to the double-layer film coating process for the acoustic device and the acoustic device package prepared by the process, the sealing performance of the acoustic device can be obviously improved, and water vapor, dust and the like can be better prevented from entering the internal space of the package body, so that the internal space is enabled to be better prevented from expanding, and the generation of bulge cracks is further inhibited. Therefore, the reliability of connection of a circuit component such as an acoustic device such as a SAW to a circuit substrate can be improved, thereby ensuring the stability and reliability of operation of the communication device. Meanwhile, the invention improves the process, and the resin sheet component is encapsulated by one-step process, thereby simplifying the process operation flow and improving the yield and the production efficiency.
In the present invention, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for manufacturing a double-layer coating of an acoustic device is characterized by comprising the following steps:
s1: providing a circuit assembly, which comprises a circuit substrate and a circuit substrate, wherein the circuit substrate is provided with a first surface and a second surface which are opposite to each other, the first surface of the circuit substrate is provided with an acoustic device, and the acoustic device and the first surface of the circuit substrate enclose a hollow structure;
s2: providing a resin sheet assembly having a first layer of resin and a second layer of resin bonded together to form the resin sheet assembly;
s3: disposing the resin sheet assembly on the circuit assembly with the first layer of resin facing in a direction of the acoustic device and the second layer of resin facing away from the acoustic device;
s4: heating and pressing the resin sheet assembly toward the circuit assembly and then curing the resin sheet assembly so that the resin sheet assembly covers the outer surface of the acoustic device and an area of the acoustic device outside a projected area of the first surface of the circuit substrate;
the first glass transition temperature of the first layer resin is 135-140 ℃, the first linear expansion coefficient of the first layer resin at the first glass transition temperature is less than 100ppm/K,
the second glass transition temperature of the second layer of resin is more than 30 ℃, and the second linear expansion coefficient of the second layer of resin at the second glass transition temperature is less than 100 ppm/K;
the layer thickness of the second layer of resin is larger than that of the first layer of resin, the second layer of resin is of a multilayer structure, and the second layer of resin is an epoxy resin film containing a heat-conducting filler and a shielding filler;
the acoustic device includes a piezoelectric oxide single crystal substrate, a resistivity in a thickness direction of the piezoelectric oxide single crystal substrate is made to be 1 × 1010-1 × 1012 Ω · cm by a redox treatment, the redox treatment being: reducing the piezoelectric oxide single crystal substrate at a temperature not higher than the curie temperature with a solid reducing agent; or heat-treating the piezoelectric oxide single crystal substrate at a temperature of 350 ℃ or higher and Curie temperature or lower in a mixed gas atmosphere of an inert gas and a reducing gas under normal pressure.
2. The acoustic device double-layer film formation method according to claim 1, wherein the first resin layer is a plastic resin and the second resin layer is a sealing resin.
3. The acoustic device double-layer film-coating manufacturing method according to claim 1, wherein the first layer resin is a plastic resin, and the second layer resin is a light-curable resin.
4. The acoustic device double-layer film-coating manufacturing method according to claim 3, wherein the first layer resin of the plastic resin satisfies, at the heating temperature of step S4: the viscosity is 50-150kPas.
5. The acoustic device double-layer film-coating manufacturing method according to claim 3, wherein the first layer resin of the plastic resin satisfies, at the heating temperature of step S4: modulus of elasticity in shear of 1X 10 5 Pa or above.
6. The acoustic device double-layered coating manufacturing method according to claim 1, wherein the first layer resin is a plastic resin having a thickness of 10um to 100 um.
7. The method of manufacturing a double-layered coating film for an acoustic device according to claim 1, wherein the heating temperature is 40 ℃ or higher and 180 ℃ or lower in step S4.
8. The acoustic device double-layer coating manufacturing method according to claim 2, wherein the density of the second layer resinA sealing resin having a shear modulus of 1X 10 5 Pa or above.
9. An acoustic device double-layer coating manufacturing method according to claim 1, wherein thermal conductivity in a thickness direction after the second layer resin is cured is smaller than thermal conductivity in a length direction.
10. The acoustic device double-layer film-coating manufacturing method according to claim 1, wherein the acoustic device is plural, and the first layer resin is divided into a plurality of sub-sheets corresponding to the plural acoustic devices.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111293530.6A CN114024520B (en) | 2021-11-03 | 2021-11-03 | Double-layer film coating process for acoustic device |
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| CN102474987A (en) * | 2009-07-17 | 2012-05-23 | 松下电器产业株式会社 | Electronic module and method for manufacturing same |
| CN105453253A (en) * | 2013-08-07 | 2016-03-30 | 日东电工株式会社 | Resin sheet for hollow electronic device encapsulation and method for manufacturing hollow electronic device package |
| CN105493270A (en) * | 2013-08-26 | 2016-04-13 | 日东电工株式会社 | Resin sheet for sealing electronic device and method for manufacturing electronic device package |
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| JP4166997B2 (en) * | 2002-03-29 | 2008-10-15 | 富士通メディアデバイス株式会社 | Surface acoustic wave device mounting method and surface acoustic wave device having resin-sealed surface acoustic wave device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102474987A (en) * | 2009-07-17 | 2012-05-23 | 松下电器产业株式会社 | Electronic module and method for manufacturing same |
| CN105453253A (en) * | 2013-08-07 | 2016-03-30 | 日东电工株式会社 | Resin sheet for hollow electronic device encapsulation and method for manufacturing hollow electronic device package |
| CN105493270A (en) * | 2013-08-26 | 2016-04-13 | 日东电工株式会社 | Resin sheet for sealing electronic device and method for manufacturing electronic device package |
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