KR20230123737A - Sensor package module and manufacturing method thereof - Google Patents

Abstract

The present invention has a substrate unit, a sensor unit laminated on one surface of the substrate unit, a lens unit laminated on one surface of the sensor unit to form a lens cavity isolated from the outside between the sensor unit, and a metal-containing material, the sensor A sensor package module disposed between the unit and the lens unit and including a bonding portion for bonding the sensor unit and the lens unit, and a method for manufacturing the same, the sensor package module capable of improving sensitivity for detecting light, and a method for manufacturing the sensor package module this is presented

Description

Sensor package module and manufacturing method of sensor package module {SENSOR PACKAGE MODULE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a sensor package module and a method of manufacturing the sensor package module, and more particularly, to a sensor package module capable of improving sensitivity for detecting light and a method of manufacturing the sensor package module.

The photosensor is a semiconductor device provided to capture an image by sensing visible light, and the infrared temperature sensor is a semiconductor device provided to measure temperature by sensing infrared light. A photo sensor and an infrared temperature sensor (hereinafter, referred to as “sensor”) are bonded to a lens and a substrate to form a package module and then mounted in a mobile device. This is called a chip scale package method.

For example, the conventional package module presented in Patent Document 1 is manufactured with a structure in which a cavity is provided between a lens housing and a substrate, and the cavity is sealed by epoxy resin, which is a kind of adhesive. In this conventional structure, heat generated by light incident on the substrate may be accumulated in the cavity. In addition, heat accumulated in the cavity may reduce the sensitivity of the sensor to detect light.

On the other hand, the sensitivity of the sensor for detecting light decreases as the cavity is closer to atmospheric pressure than vacuum. However, the conventional structure cannot control the pressure of the cavity by vacuum when manufacturing the package module. That is, the cavity can be controlled at atmospheric pressure. Accordingly, the sensitivity of the sensor to detect light may be reduced due to the air particles inside the cavity.

The background technology of the present invention is published in the following patent documents.

KR 10-0915134 B1

The present invention provides a sensor package module capable of improving sensitivity for detecting light and a method for manufacturing the sensor package module.

A sensor package module according to an embodiment of the present invention includes a substrate; a sensor unit laminated on one surface of the substrate unit; a lens unit stacked on one surface of the sensor unit to form a lens cavity isolated from the outside between the sensor unit; and a bonding portion having a metal-containing material, disposed between the sensor unit and the lens unit, and bonding the sensor unit and the lens unit together.

The substrate portion may have a through-electrode for connecting the other surface opposite to one surface of the substrate portion to one surface of the substrate portion.

The sensor unit may have a sensor element on one surface and an input/output pad electrically connected to the sensor element and connected to the substrate unit by wire bonding.

a connecting portion for connecting the input/output pad and the board through wire bonding; It may include a metal-containing material, and an attachment part for attaching the other surface opposite to one surface of the sensor part to the substrate part.

It may include; a readout integrated circuit substrate portion bonded to the other surface of the substrate portion.

In order to seal the lens cavity, the junction part includes a conductive bump formed on the sensor unit in a closed loop shape surrounding the circumference of the lens cavity, and the lens unit faces the sensor unit so as to be bonded to the conductive bump. It may include a bonding pattern formed on the other side of the view.

The junction part may include a conductive thin film formed in a closed loop shape between the other surface of the lens part and the sensor part, surrounding the circumference of the lens cavity, to seal the lens cavity.

The substrate portion includes a plurality of through electrodes, some of the plurality of through electrodes form a signal path for transmitting an electrical signal, and the remaining through electrodes among the plurality of through electrodes form a path different from the signal path. A heat dissipation path for dissipating heat may be formed.

The substrate portion, the parent material; a plurality of through electrodes formed to penetrate the base material; a first wiring pattern formed on one surface of the base material, connected to some of the plurality of through electrodes, and connected to the sensor unit through wire bonding; a second wiring pattern formed on the other surface opposite to one surface of the base material and connected to some of the through electrodes; a third wiring pattern formed on one surface of the base material, connected to the remaining through electrodes among the plurality of through electrodes, and brought into thermal contact with the sensor unit; and a fourth wiring pattern formed on the other surface of the base material and connected to the remaining through electrodes.

A heat dissipation path connecting the lens cavity and the other surface of the base material is formed by the junction part, the sensor part, the third wiring pattern, the remaining through electrodes, and the fourth wiring pattern, and the first wiring pattern and the part of the base material are formed. A signal path connecting the sensor unit and the other surface of the base material is formed by the through electrode and the second wiring pattern, and the signal path may be separated from the heat dissipation path.

The sensor unit may include a body for forming a sensor cavity; a membrane formed on one surface of the body to seal one side of the sensor cavity; a sensor element formed on the membrane; It may include an input/output pad formed on one surface of the body and electrically connected to the sensor element.

A method of manufacturing a sensor package module according to an embodiment of the present invention includes preparing a substrate; Bonding the lower surface of the sensor unit on the substrate unit; connecting a partial area of an upper surface of the sensor unit with a partial area of the substrate unit; disposing a lens unit on the sensor unit; and bonding the sensor unit and the lens unit using a bonding unit having a metal-containing material.

The process of preparing the substrate unit may include forming a plurality of through electrodes to penetrate the base material; forming first and second wiring patterns on one surface and the other surface of the base material to be connected to some of the plurality of through electrodes; and forming third and fourth wiring patterns on one surface and the other surface of the base material so as to be connected to the remaining through electrodes except for the partial through electrodes.

The bonding of the lower surface of the sensor unit to the substrate unit may include disposing the sensor unit on the substrate unit so as to overlap at least a portion of the third wiring pattern; forming a bonding layer having a metal-containing material between the substrate and the sensor; bonding the substrate part and the sensor part to the bonding layer; and thermally connecting the sensor unit, the third wiring pattern, the remaining through electrode, and the fourth wiring pattern by using the metal-containing material in the bonding layer.

The process of connecting a partial area of the upper surface of the sensor unit to a partial area of the substrate unit is to connect the first wiring pattern and the input/output terminals of the sensor unit through wire bonding, and thereby connect the sensor unit and the wire to the first wiring pattern and the first wiring pattern. A process of electrically connecting a portion of the through electrode and the second wiring pattern; may be included.

The process of bonding the sensor unit and the lens unit may include forming a lens cavity between the lens unit and the sensor unit.

The forming of the lens cavity may include bringing an edge of the concave groove formed in the lens unit into contact with the sensor unit; A process of bonding an edge of the concave groove and the sensor unit to form a sealed lens cavity; may include.

The process of bonding the edge of the concave groove and the sensor unit may include contacting a bonding pattern formed on the lens unit and a conductive bump having a closed loop shape and having a metal-containing material formed on the sensor unit; A process of bonding the bonding pattern and the bonding portion of the conductive bump by heat treatment.

The process of bonding the edge of the concave groove and the sensor unit may include disposing a conductive thin film having the metal-containing material and having an intermittent loop shape between the lens unit and the sensor unit; It may include; a process of curing and expanding the conductive thin film and bonding it in a closed loop shape.

The process of contacting the conductive bumps and the process of bonding by heat treatment may be performed in a vacuum atmosphere.

According to an embodiment of the present invention, by bonding the lens unit and the sensor unit with a bonding unit having a metal-containing material, a heat dissipation path may be formed in a direction from the lens unit to the sensor unit using the metal-containing material. Therefore, before heat generated in the sensor unit by light incident is accumulated in the lens unit and increases the temperature of the lens cavity, the heat can be dissipated toward the sensor unit along the heat dissipation path. Contamination and damage to the sensor unit due to accumulated heat may be prevented, and sensitivity of the sensor unit to detect light may be improved.

In addition, according to an embodiment of the present invention, the joint strength of the junction can be improved by using a metal-containing material. Therefore, even when the pressure in the lens cavity is lower than the atmospheric pressure and the pressure difference between the lens cavity and the atmospheric pressure is maintained, the junction is not damaged and the pressure in the lens cavity can be maintained at a low level. From this, it is possible to control the pressure of the lens cavity to a pressure lower than the atmospheric pressure, so that the sensitivity of the sensor unit to detect light can be improved.

1 is a schematic diagram of a sensor package module according to an embodiment of the present invention.
2 is a schematic diagram of a sensor package module according to another embodiment of the present invention.
3 to 5 are process charts for explaining a method of manufacturing a sensor package module according to an embodiment of the present invention.
6 and 7 are process charts for explaining a method of manufacturing a sensor package module according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and will be implemented in a variety of different forms. Only the embodiments of the present invention are provided to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention. In order to explain an embodiment of the present invention, the drawings may be exaggerated, parts irrelevant to the description may be omitted from the drawings, and like reference numerals in the drawings refer to the same elements.

The present invention relates to a sensor package module and a method for manufacturing the sensor package module, and is applied to a thermopile sensor package module that detects infrared light emitted from an area of interest to measure radiant energy and observes the area of interest. An embodiment of the present invention will be described in detail by exemplifying the case of being.

Of course, the sensor package module and the manufacturing method of the sensor package module according to an embodiment of the present invention can be applied as various types of sensor package modules that can sense light of various wavelengths and generate electrical signals therefrom.

1 is a schematic diagram of a sensor package module according to an embodiment of the present invention.

Referring to FIG. 1 , a sensor package module according to an embodiment of the present invention will be described in detail.

The sensor package module according to an embodiment of the present invention includes a substrate unit 100, a sensor unit 400 stacked on one surface of the substrate unit 100, and a lens cavity C1 isolated from the outside between the sensor unit 400. ) has a lens unit 700 laminated on one surface of the sensor unit 400, a metal-containing material, and is disposed between the sensor unit 400 and the lens unit 700, and the sensor unit 400 and the lens It includes a joint portion 800 joining the portion 700.

In addition, the sensor package module according to an embodiment of the present invention has a metal-containing material, and the attachment part 500 for attaching the other surface opposite to one surface of the sensor part 400 to the substrate part 100, the sensor part ( 400), a connection part 600 for connecting one surface of the board unit 100, a readout integrated circuit board unit 200 bonded to the other side opposite to one side of the substrate unit 100, and a readout integrated circuit board unit 200 It may include a solder ball part 300 arranged along the circumference and bonded to the other surface of the substrate part 100 . In addition, the sensor package module according to an embodiment of the present invention includes a molding unit 900 covering a part of the lens unit 700, the sensor unit 400, the substrate unit 100, and the read integrated circuit board unit 200. can include

The substrate unit 100 is a main body of the sensor package module and serves to support the overall structure of the sensor package module. The shape of the substrate unit 100 may vary. The substrate unit 100 may have a rectangular plate shape. Also, the substrate unit 100 may have a disk shape. The substrate unit 100 may include a plurality of connecting surfaces for connecting one surface and the other surface facing each other and edges of the one surface and the other surface. In this case, one surface may be an upper surface, the other surface may be a lower surface, and the connection surface may be a side surface. Of course, according to the direction in which the sensor package module is disposed, one surface, the other surface, and the connection surface may be defined in various ways. The substrate portion 100 may have a predetermined area in a horizontal direction and may have a predetermined thickness in a vertical direction. At this time, the area of the substrate unit 100 may be such that the sensor unit 400 and the connection unit 600 may be disposed on one surface of the substrate unit 100, and the read integrated circuit board unit 200 may be disposed on the lower surface of the substrate unit 100. and a predetermined area in which the solder ball unit 300 can be placed. In addition, the thickness of the substrate portion 100 may be in the range of 60 micrometers to 400 micrometers. Meanwhile, the substrate unit 100 may be made of a printed circuit board, a ceramic board, or a glass board.

The base material 110, a plurality of through electrodes 120, a first wiring pattern 130, a second wiring pattern 140, a third wiring pattern 150, a fourth wiring pattern ( 160), a first stress buffer layer 170 and a second stress buffer layer 180.

The base material 110 is a main body of the substrate part 100, forms the outer shape of the substrate part 100, and serves to support the structure of the substrate part 100. A plurality of through electrodes 120 may be disposed inside the base material 110 in a direction penetrating from one surface to the other surface. In addition, the first and third wiring patterns 130 and 150 may be disposed on one surface of the base material 110 in a horizontal direction. In addition, the base material 110 may have second and fourth wiring patterns 140 and 160 disposed in a horizontal direction on the other surface.

The plurality of through electrodes 120 are through electrodes for connecting the other surface of the substrate part 100 to one surface of the substrate part 100, and serve to transfer electrical signals and heat from one surface side of the substrate part 100 to the other surface side. And, serves to move the electrical signal from the other surface side of the substrate unit 100 to one surface side. The plurality of through electrodes 120 may be formed to penetrate the base material 110 in a vertical direction. A through electrode for moving an electric signal and a through electrode for moving heat may be different from each other. That is, some of the through electrodes 120a among the plurality of through electrodes 120 form a signal path S for transmitting electrical signals, and the remaining through electrodes 120b among the plurality of through electrodes 120 are different from the signal path. A heat dissipation path H for radiating heat through the path may be formed.

Specifically, the plurality of through electrodes 120 include some through electrodes 120a connecting the first wiring pattern 130 and the second wiring pattern 140, the third wiring pattern 150 and the fourth wiring pattern ( 150) may be included. In addition, some through electrodes 120a serve to transfer electrical signals from the first wiring pattern 130 to the second wiring pattern 140 and from the second wiring pattern 140 to the first wiring pattern 130. do. In addition, the remaining through electrodes 120b serve to transfer heat from the third wiring pattern 150 to the fourth wiring pattern 150 . The number of some through electrodes 120a may be plural, and the number of the remaining through electrodes 120b may also be plural. Some of the through electrodes 120a may be relatively closer to the edge side of the base material 110 in the horizontal direction than the other through electrodes 120b. The remaining through electrodes 120b may be relatively closer to the center of the base material 110 in the horizontal direction than some of the through electrodes 120a. Meanwhile, each of the plurality of through electrodes 120 may include a via hole formed to penetrate the base material 110 in a vertical direction and a metal electrode filled in the via hole. Here, the metal electrode may include, for example, a copper material.

The first wiring pattern 130 may be formed on one surface of the base material 110, connected to a portion of the through electrode 120a, and connected to the sensor unit 400 by wire bonding. The second wiring pattern 140 may be formed on the other surface of the base material 110 and may be partially connected to through electrodes 120a. The third wiring pattern 150 is formed on one surface of the base material 110, is connected to the through electrodes 120b other than some of the through electrodes 120a, and may be in thermal contact with the sensor unit 400. The fourth wiring pattern 160 may be formed on the other surface of the base material 110 and connected to the remaining through electrodes 120b.

The first, second, third, and fourth wiring patterns 130, 140, 150, and 160 may extend in a horizontal direction, each may have a different predetermined shape, and may be spaced apart from each other. The first wiring pattern 130 may be electrically connected to the connector 600 . Also, the second wiring pattern 140 may be electrically connected to the read integrated circuit board part 200 and the solder ball part 300 . Also, the third wiring pattern 150 may be thermally connected to the sensor unit 400 . The fourth wiring pattern 160 may be thermally connected to a space on the other side of the base material 110 .

Here, being electrically connected means being directly connected to transmit an electrical signal. In addition, being thermally connected means being directly or indirectly connected so that heat can be transferred.

The first stress buffer layer 170 may extend in a horizontal direction from one surface of the base material 110 to cover one surface of the base material 110 and the first and third wiring patterns 130 and 150 . In this case, the first stress buffer layer 170 may expose a partial area of the first wiring pattern 130 and a partial area of the third wiring pattern 150 . In addition, the second stress buffer layer 180 may extend in a horizontal direction from the other surface of the base material 110 to cover the other surface of the base material 110 and the second and fourth wiring patterns 140 and 160 . In this case, the second stress buffer layer 180 may expose a partial area of the second wiring pattern 140 and a partial area of the fourth wiring pattern 160 . The first stress buffer layer 170 and the second stress buffer layer 180 may be a kind of passivation layer and may include a polymer material. Of course, the material of these buffer films may vary.

The readout integrated circuit board unit 200 receives and processes the electrical signal generated by the sensor unit 400, and transmits the processed electrical signal to a device (not shown) on which the sensor package module is mounted through the solder ball unit 300. play a role Here, processing may refer to signal processing for reading desired information from electrical signals. In this case, the desired information may be temperature information or thermal image information of the region of interest observed by the sensor package module. Of course, the type of desired information may be various, such as optical image information.

The readout integrated circuit board unit 200 may be bonded to the other surface of the substrate unit 100 . Specifically, the read integrated circuit board unit 200 may be bonded to the exposed area of the second wiring pattern 140 of the substrate unit 100 . The read integrated circuit board unit 200 may be positioned closer to the center side than to the edge side of the substrate unit 100 in the horizontal direction. The thickness of the read integrated circuit board unit 200 in the vertical direction may be smaller than the thickness of the solder ball unit 300 in the vertical direction. For example, the thickness of the read integrated circuit board unit 200 in the vertical direction may be in the range of 60 micrometers to 150 micrometers. An area of the read integrated circuit board unit 200 in a horizontal direction may be smaller than an area of the substrate unit 100 in a horizontal direction.

The read integrated circuit board unit 200 may include a read integrated circuit board 210 , bumps 220 and pads 230 . The readout integrated circuit board 210 is a main body of the readout integrated circuit board unit 200 and may be a predetermined board on which a circuit for signal processing of electrical signals is mounted. A plurality of bumps 220 may be disposed on one surface, for example, the upper surface of the read integrated circuit board 210, and a plurality of pads 230 may be provided and disposed on one surface, for example, the upper surface of each bump 220, respectively. The bump 220 and the pad 230 serve to support the read integrated circuit board 210 to the substrate 100 and to electrically connect the read integrated circuit board 210 to the substrate 100. .

The bumps 220 and the pads 230 may include silver-tin alloy, gold, or the like, and the read integrated circuit board 210 may be bonded to the substrate unit 100 by a liquid phase diffusion bonding method. Of course, the manner in which the bump 220 and the pad 230 bond the readout integrated circuit board 210 to the substrate 100 may vary. A total thickness of the bumps 220 and the pads 230 in the vertical direction may be in the range of 20 micrometers to 40 micrometers.

The solder ball part 300 serves to bond the sensor package module to the device and transmits the electrical signal processed by the read integrated circuit board part 200 to the device. A plurality of solder ball units 300 may be provided and may be arranged along the circumference of the read integrated circuit board unit 200 . Also, the solder ball part 300 may be bonded to the exposed area of the second wiring pattern 140 on the other surface of the substrate part 100 . The solder ball part 300 may be a spherical member having a predetermined diameter. The solder ball part 300 may include a tin-silver-copper alloy. Of course, the shape and material of the solder ball unit 300 may vary.

The sensor unit 400 serves to receive light emitted from a region of interest to be observed by the sensor package module and to generate an electrical signal therefrom. The sensor unit 400 may have a sensor cavity C2. Also, the outer shape of the sensor unit 400 may vary. For example, the sensor unit 400 may have a rectangular cylinder shape. Of course, the sensor unit 400 may also have a cylindrical shape. The sensor unit 400 may be stacked on one surface of the substrate unit 100 and may be attached to the substrate unit 100 by the attachment unit 500 . Also, the sensor unit 400 may be electrically connected to the substrate unit 100 by wire bonding. The sensor unit 400 may have a predetermined area in a horizontal direction and may have a predetermined thickness in a vertical direction. In this case, the area of the sensor unit 400 may be smaller than the area of the substrate unit 100 in the horizontal direction and may be larger than the area of the lens unit 700 in the horizontal direction. In addition, the thickness of the sensor unit 400 may be in the range of 200 micrometers to 725 micrometers.

The sensor unit 400 may include a body 410 , a membrane 420 , a sensor element (not shown), and an input/output pad 430 . The body 410 is the main body of the sensor unit 400, and serves to position the sensor element at the focal position of the light. The body 410 may include a silicon material, and an opening for forming the sensor cavity C2 may be formed in the center thereof.

The sensor cavity C2 is a space defined by an opening formed in the body 410, and may be, for example, a space inside the opening. The sensor cavity C2 may be positioned between the membrane 420 and the substrate unit 100 . In addition, the upper portion of the sensor cavity C2 may be sealed by the membrane 420 and the lower portion may be sealed by the substrate portion 100 and the attachment portion 500 . The sensor cavity C2 serves as a buffer space capable of accommodating displacement generated in the sensor element and the membrane 420 on which the sensor element is formed by light incident on the sensor element. The pressure inside the sensor cavity C2 may be the same as or similar to the pressure inside the lens cavity C1 within a predetermined error range.

The membrane 420 serves as a substrate on which a sensor element is formed and supports the sensor element. The membrane 420 may be formed on one surface of the body 410 to cover one end of the opening formed in the body 410 . The membrane 420 may be made of the same material as the body 410 and may have an integral structure with the body 410 . For example, the membrane 420 may be formed by etching a predetermined portion of the other surface of the body 410 in a direction from the other surface to one surface of the body 410 to leave only a predetermined thickness. Of course, the method of forming the membrane 420 on the body 410 may vary.

The sensor element serves to generate an electrical signal by receiving light transmitted through the lens unit 700 . This sensor element may be a sensor element for taking a thermal image. Of course, the types of sensor elements may vary. That is, the sensor element may be a conversion element of various types that satisfies that it can generate an electrical signal by receiving light. The sensor element may be formed on one surface of the membrane 420 .

The input/output pad 430 serves to output an electrical signal from the sensor element to the substrate 100 and to input a control signal from the substrate 100 to the sensor element. At this time, the control signal may be a control signal for operating the sensor element. At least one input/output pad 430 may be formed at a predetermined location on one surface of the body 410 . Also, the input/output pad 430 may be electrically connected to the sensor element through a predetermined wire (not shown). Also, the input/output pad 430 may be connected to the board unit 100 through wire bonding through the connection unit 600 .

The attachment part 500 has a metal-containing material and serves to attach the other surface of the sensor part 400 to one surface of the substrate part 100 . Here, the metal-containing material serves to dissipate heat from the sensor unit 400 to the substrate unit 100, and may refer to a material containing metal with high thermal conductivity, for example. At this time, high thermal conductivity means higher thermal conductivity than the epoxy resin. Of course, the reference material of thermal conductivity may be various. For example, high thermal conductivity may mean higher thermal conductivity than the lens unit 700 . In an embodiment of the present invention, silver (Ag) is exemplified as a metal-containing material. At this time, silver may be in the form of powder or granules having a predetermined shape. That is, the attachment portion 500 may be formed by curing silicon-based epoxy or resin-based epoxy having a metal-containing material in the form of powder or granules.

The attaching portion 500 may have a film shape having a predetermined area in the horizontal direction and a predetermined thickness in the vertical direction. One surface of the attaching unit 500 may contact the other surface of the sensor unit 400 and the other surface may contact the third wiring pattern 150 of the board unit 100 . An area of the attaching unit 500 in the horizontal direction may be more than half the size of the area of the other surface of the sensor unit 400 in the horizontal direction.

The connection part 600 serves to connect the input/output pad 430 of the sensor part 400 and the first wiring electrode 130 of the board part 100 by wire bonding. The connection unit 600 may be, for example, a wire. The connection unit 600 can transmit an electric signal generated by the sensor unit 400 by light incident to the first wiring electrode 130, and transmits a control signal from the first wiring electrode 130 to the sensor unit 400. can be sent In this case, the wire bonding method may have better transmission/reception sensitivity of electrical signals than the flip chip bonding method.

The lens unit 700 serves to form a focus by concentrating light irradiated from the outside onto the sensor unit 400 . The lens unit 700 may be stacked on one surface of the sensor unit 400 to form a lens cavity C1 isolated from the outside between the sensor unit 400 and the sensor unit 400 . The lens unit 700 may have a predetermined area in a horizontal direction and may have a predetermined thickness in a vertical direction. In this case, the area of the lens unit 700 may be smaller than the entire area of the sensor unit 400 and may be larger than the area of the membrane 420 of the sensor unit 400 . Also, the thickness of the lens unit 700 may be in the range of 200 micrometers to 725 micrometers. The other surface of the lens unit 700 may be bonded to one surface of the sensor unit 400 by the bonding unit 800 .

The lens unit 700 is a convex member convexly formed on one surface of the lens body 710 to form a focus of light while advancing the lens body 710 and light incident to the lens body 710 toward the sensor unit 400. 710, the other surface of the lens body 710 to provide a focal distance between the lens body 710 and the sensor unit 400 to form a focus of light on the sensor unit 400 by propagating light. A concave groove 730 concavely formed in the lens body 710, a bonding pattern 740 formed on the other surface of the lens body 710, having a closed loop shape, and bonded to the bonding portion 800, and the bonding pattern 740 are bonded to the bonding portion ( 800), it is formed to cover the bonding pattern 740 in order to buffer the impact, and may include a buffer film 750 that exposes the bonding pattern 740 to the bonding portion 800 with a partial portion open. there is. Here, the lens cavity C1 may be formed to include an inner space of the concave groove 730 .

Meanwhile, the sensor package module may have various modifications in the structure and shape of one surface of the lens body 710 . For example, one surface of the lens body 710 may be formed to be flat. That is, the lens unit 700 may not include the convex member 710 .

The bonding part 800 serves to bond the lens unit 700 to the sensor unit 400, maintains the sealing of the lens cavity C1, and transmits heat between the lens cavity C1 and the lens unit 700 to the sensor. It serves to dissipate heat to the unit 400. To this end, the bonding portion 800 may have a metal-containing material for dissipating heat from the lens cavity C1 and the lens unit 700 to one surface of the sensor unit 400 . In addition, the bonding unit 800 may be disposed between the sensor unit 400 and the lens unit 700 to bond them. In this case, the bonding portion 800 may include a conductive bump having a closed loop shape to surround the lens cavity C1 and maintain a vacuum in the lens cavity C1. The conductive bumps may also be referred to as thermally conductive bumps. Here, the conductive bumps may have, for example, a thickness of about 40 micrometers or less. Such a conductive bump may include, for example, a base layer 810 bonded to one surface of the sensor unit 400 and a bonding layer 820 bonded to the lens unit 700. Of course, the structure of the conductive bumps may vary. Meanwhile, when the junction 800 includes the conductive bump, the metal-containing material may include, for example, a silver-tin alloy and copper, or may include silver and copper. Also, when the bonding portion 800 includes the conductive bump, the lens cavity C1 may be vacuum-controlled.

The molding part 900 serves to cover a part of the lens part 700, the sensor part 400, the substrate part 100, and the read integrated circuit board part 200. The molding unit 900 may include a first molding 910 formed on one side of the substrate unit 100 and a second molding 920 formed on the other side of the substrate unit 100 . The first molding 910 may expose one surface of the lens unit 700 and cover the remaining surfaces of the lens unit 700 except for one surface and the connection part 600 . Here, the remaining surfaces include the sensor unit 400, the lens unit 700, the attachment unit 500, the connection unit 600, and the bonding portion located on one side of the substrate unit 100, including one side of the substrate unit 100. Among all surfaces exposed to the outside of 800 , other surfaces except for one surface of the lens unit 700 may be referred to. The second molding 920 may expose the other side of the solder ball unit 300 in the vertical direction, and may cover surfaces of the other side of the board unit 100 except for this. In this case, the thickness of the second molding 920 may be in the range of 30 micrometers to 100 micrometers. The molding part 900 may include a material capable of blocking infrared light. In addition, a method of forming the molding part 900 may be various. For example, the molding part 900 may be formed by applying epoxy containing a material capable of blocking infrared light to a surface on which the molding part 900 is to be formed, and curing the applied epoxy by applying heat. Before curing the applied epoxy, a predetermined film (not shown) may be brought into contact with the applied epoxy, and the epoxy applied with the film may be pressurized and spread in a horizontal direction. For example, when the second molding 920 is formed, epoxy is applied, and then the epoxy is pressurized using a film and spread in a horizontal direction, thereby extending the narrow space between the solder ball part 300 and the other surface of the substrate part 100. You can infiltrate the epoxy. On the other hand, there may be various types of epoxy including a material capable of blocking infrared light.

As described above, in the embodiment of the present invention, in order to seal the lens cavity C1, the bonding portion 800 surrounds the lens cavity C1 and is formed on the sensor unit 400 in a closed loop shape. While including (810, 820), the lens unit 400 may include a bonding pattern 740 formed on the other surface facing the sensor unit 400 so as to be bonded to the conductive bumps 810 and 820. Therefore, even if the pressure of the lens cavity C1 is lower than the atmospheric pressure, the conductive bumps 810 and 820 and the bonding pattern 740 are not damaged, and the pressure difference between the lens cavity C1 and the atmospheric pressure can be stably endured. can Accordingly, the pressure of the lens cavity C1 may be set to a pressure lower than the atmospheric pressure, whereby the strength of the sensor unit 400 detecting light may be improved. Of course, it is possible to effectively dissipate heat from the lens unit 700 to the sensor unit 400 by using the conductive bumps 810 and 820 and the bonding pattern 740, and thus the heat remains in the lens cavity C1. By preventing this from happening, the strength of the sensor unit 400 detecting light can be improved.

In addition, according to the above-described embodiment of the present invention, the sensor package module includes the junction part 800, the sensor part 400, the attachment part 500, the third wiring pattern 150, the remaining through electrodes 120b, and the second through electrode 120b. A heat dissipation path connecting the lens cavity C1 and the other surface of the base material 110 may be formed using the 4 wiring pattern 160 . In addition, the sensor package module connects the sensor unit 400 and the other surface of the base material 110 using the bonding portion 800, the first wiring pattern 130, some through electrodes 120a, and the second wiring pattern 140. signal pathways can be formed. Also, the signal path may be separated from the heat dissipation path to prevent thermal contamination. Therefore, in the embodiment of the present invention, the heat of the lens unit 700 can be smoothly dissipated to the substrate unit 100 by using the heat dissipation path, and electrical signals can be stably transmitted and received through the signal path separated from the movement of heat. can Therefore, the sensor package module according to an embodiment of the present invention can further improve the sensitivity of sensing light by the sensor unit 400 .

Although an embodiment of the present invention has been described with reference to FIG. 1 , the present invention may be configured in various ways, including the following other embodiments.

2 is a schematic diagram of a sensor package module according to another embodiment of the present invention.

Referring to FIG. 2 , a sensor package module according to another embodiment of the present invention will be described. At this time, features distinguished from the embodiments will be described in detail, and overlapping descriptions will be omitted or simply described.

In the sensor package module according to another embodiment of the present invention, the configuration of the junction part 800' may be different from that of the embodiment.

The junction part 800' according to another embodiment of the present invention may include a conductive thin film having a closed loop shape to surround the lens cavity C1 and maintain a seal of the lens cavity C1. The conductive thin film may have a thickness ranging from 10 micrometers to 15 micrometers. In addition, the conductive thin film may have an area equal to or greater than half of the area of the other surface of the lens unit 700 .

Such a conductive thin film may be formed by curing epoxy having a metal-containing material. In this case, the metal-containing material may include silver, and silver may be included in the epoxy in the form of powder or granules. In addition, when the bonding portion 800' is a conductive thin film, the lens cavity C1 may be sealed with a predetermined pressure lower than atmospheric pressure and higher than vacuum. Here, the vacuum may mean a vacuum of a size capable of maintaining the conductive bumps without being destroyed by a pressure difference between the atmospheric pressure and the lens cavity C1.

Meanwhile, the conductive thin film may be more advantageous in thermal conduction than the conductive bump. Accordingly, a heat dissipation effect from the lens unit 700 to the substrate unit 100 through the heat dissipation path may be further improved.

That is, as described above, in another embodiment of the present invention, in order to seal the lens cavity C1, the bonding portion 800' surrounds the lens cavity C1, and the other surface of the lens unit 700 and the sensor A conductive thin film formed in a closed loop shape may be included between the parts 400 . As such, by bonding the lens unit 700 and the sensor unit 400 with the conductive thin film, the heat dissipation effect from the lens unit 700 to the sensor unit 400 can be further improved. From this, by effectively preventing heat from being stagnant in the lens cavity C1, the sensor unit 400 can further improve the strength of detecting light.

3 to 5 are process charts for explaining a method of manufacturing a sensor package module according to an embodiment of the present invention.

A manufacturing method of a sensor package module according to an embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 5 .

A method of manufacturing a sensor package module according to an embodiment of the present invention includes the steps of preparing a substrate 100, bonding the lower surface of the sensor unit 400 on the substrate 100, and the sensor unit 400. ) using a process of connecting a partial area of the upper surface of the substrate unit 100 with a partial area of the substrate unit 100, a process of disposing the lens unit 700 on the sensor unit 400, and a bonding unit 800 having a metal-containing material. Thus, a process of bonding the sensor unit 400 and the lens unit 700 is included.

In addition, in the manufacturing method of the sensor package module according to an embodiment of the present invention, between the process of preparing the substrate unit 100 and the process of bonding the lower surface of the sensor unit 400 on the substrate unit 100, the substrate unit A process of bonding the read integrated circuit board unit 200 and the solder ball unit 300 to the second wiring pattern of (100) may be included.

In addition, in the manufacturing method of the sensor package module according to an embodiment of the present invention, after the process of bonding the sensor unit 400 and the lens unit 700, a part of the lens unit 700, the sensor unit 400, and the substrate A process of covering the unit 100 with the molding unit 900 to block external light other than light incident on, for example, one surface of the light incident surface of the lens unit 700 may be included.

First, the substrate portion 100 is prepared. A plurality of through electrodes 120 are formed by preparing a base material 110 to be the main body of the substrate unit 100, forming a plurality of via holes to pass through the base material 110, and then forming metal wires in the plurality of via holes. form In addition, first and second wiring patterns 130 and 140 are deposited on one surface and the other surface of the base material 110 to be connected to some through electrodes 120a to be used for transmitting and receiving electrical signals among the plurality of through electrodes 120. do. In addition, the third and fourth wiring patterns 150 and 160 are formed by depositing on one surface and the other surface of the base material 110 to be connected to the remaining through electrodes 120b to be used for heat dissipation among the plurality of through electrodes 120. Thereafter, first and second stress buffer films 170 and 180 are formed to cover one side and the other side of the base material 110 and the first to fourth wiring patterns 130 , 140 , 150 , and 160 . Thereafter, the predetermined area of the third wiring pattern 150 to be in contact with the attachment part 500 and the predetermined area of the fourth wiring pattern 160 to be exposed to the outside, and the first wiring pattern to be in contact with the connection part 600 ( 130) and a predetermined area of the second wiring pattern 140 to be in contact with the solder ball unit 300 and the read integrated circuit board unit 200 are exposed. ) to remove multiple positions.

Thereafter, the read integrated circuit board unit 200 and the solder ball unit 300 are bonded to the second wiring pattern 140 of the substrate unit 100 . Referring to FIG. 3 , after the substrate 100 is seated on a predetermined stage (not shown) so that the other surface of the substrate 100 faces upward, the second wiring to which the read integrated circuit board 200 is bonded. After disposing the bump 220 and the pad 230 at the position of the pattern 140 and placing the readout integrated circuit board 210 on the bump 220, they are bonded by a flip chip bonding method. In addition, after disposing the solder ball parts 300 at the positions of the second wiring patterns 140 to which the solder ball parts 300 are to be bonded, they are joined by a reflow method. Thereafter, the substrate unit 100 is vertically inverted so that the solder ball unit 300 faces downward.

Then, the lower surface of the sensor unit 400 is bonded to the substrate unit 100 . Referring to FIG. 4 , the sensor unit 400 is spaced apart from each other on the substrate 100 so as to overlap at least a portion of the third wiring pattern 150 of the substrate 100 . In this case, the membrane 420 may face upward and the sensor cavity C2 may face downward. An attachment portion 500 having a metal-containing material is formed between the substrate portion 100 and the sensor portion 400 . At this time, the attachment portion 500 is in a state where the epoxy in the attachment portion 500 is not cured, and is applied in a loop shape to cover at least a portion of the third wiring pattern 150 . Thereafter, the sensor unit 400 is lowered and seated on the attachment unit 500. In addition, the attachment unit 500 is cured using heat, ultraviolet light, etc. to bond the substrate unit 100 and the sensor unit 400 together. At this time, while the epoxy of the attachment part 500 is cured, its volume increases, it can change from a loop shape to a closed loop shape, and the sensor cavity C2 can be sealed. The sensor unit 400, the third wiring pattern 150, the remaining through electrodes 120b, and the fourth wiring pattern 160 are thermally connected by using the containing material.

Thereafter, a partial area of the upper surface of the sensor unit 400 is connected to a partial area of the substrate unit 100 . That is, after contacting one end of the wire of the connection part 600 to the input/output pad 430 of the sensor unit 440 and contacting the other end of the connection part 600 to the first wiring pattern 130 of the board unit 100, , The first wiring pattern 130 and the sensor unit 400 are connected by wire bonding, and the sensor unit 400, the wire, the first wiring pattern 130, some through electrodes 120a, and the second wiring pattern 140 ) is electrically connected. A signal path may be formed in this process.

Then, the lens unit 700 is disposed on the sensor unit 400 . That is, referring to FIGS. 4 and 5 , the lens unit 700 is spaced apart from one side of the sensor unit 400 and positioned.

Thereafter, the sensor unit 400 and the lens unit 700 are bonded. This process may include a process of forming a lens cavity C1 between the lens unit 700 and the sensor unit 400 . In the process of forming the lens cavity C1, the concave groove 730 of the lens unit 700 is disposed downward, the edge of the concave groove 730 is in contact with the sensor unit 400, and the concave groove ( 730) and the sensor unit 400 are bonded to form a sealed lens cavity C1. Specifically, the bonding pattern formed on the lens unit 700 and the conductive bumps 810 and 820 having a metal-containing material formed on the sensor unit 400 and having a closed loop shape are brought into contact and bonded by heat treatment. can From this, a lens cavity C1 may be formed between the lens unit 700 and the sensor unit 400 .

That is, a junction part 800 having a metal-containing material and having a closed loop shape, ie, a conductive bump, is disposed between the lens unit 700 and the sensor unit 400 . Thereafter, the bonding portion 800 is seated on one surface of the sensor unit 400 and the bonding portion 800 is brought into contact with the bonding pattern 740 provided on the other surface of the lens unit 700 . Then, a heat treatment, such as a reflow process, is performed to bond the lens unit 700 and the sensor unit 400 to the conductive bump to isolate the lens cavity C1 and maintain a vacuum in the lens cavity C1. In this process, a heat dissipation path may be formed.

At this time, the process of contacting the conductive bumps and the process of bonding by heat treatment are performed in a vacuum atmosphere. That is, the inside of a chamber (not shown) in which the sensor package module is manufactured is vacuumed. Accordingly, it is possible to form a vacuum in the lens cavity C1 with the vacuum of the chamber.

Then, as shown in FIG. 1, a part of the lens unit 700, the sensor unit 400, and the substrate unit 100 are covered with the molding unit 900 so that the light incident surface of the lens unit 700, for example, is incident on one surface. Blocks the rest of the external light except for the light to be used. At this time, the molding unit 900 is to be formed by a series of processes of applying epoxy containing a material capable of blocking infrared light to the surface to be covered with the molding unit 900 and curing by applying heat to the applied epoxy. can In addition, between the process of applying the epoxy and the process of curing the applied epoxy, a process of pressing and spreading the applied epoxy as a film may be further included. Meanwhile, the above-described processes may be performed at a wafer level.

The sensor package module manufactured by the above-described process can form a heat dissipation path separated from the signal path by bonding the lens unit 700 and the sensor unit 400 with the bonding unit 800 having a metal-containing material. The lens unit 700 and the lens unit ( 700) and the sensor unit 400 connected with the lens cavity C1 therebetween can be prevented from being contaminated by heat, thereby improving the sensitivity of the sensor unit 400 to detect light.

6 and 7 are process charts for explaining a method of manufacturing a sensor package module according to another embodiment of the present invention. A manufacturing method of a sensor package module according to another embodiment of the present invention will be described with reference to FIGS. 2, 6, and 7 . At this time, features distinguished from the embodiments will be described in detail, and overlapping descriptions will be omitted or simply described.

In a method of manufacturing a sensor package according to another embodiment of the present invention, in the process of bonding the edge of the concave groove 730 and the sensor unit, a metal is formed between the lens unit 700 and the sensor unit 400 as the bonding unit 800'. Epoxy containing material is applied in an intermittent loop shape to form a loop-shaped conductive thin film, and heat is applied to the conductive thin film to harden and expand the conductive thin film to bond into a closed loop shape. Of course, the conductive thin film is cured in an intermittent loop shape, epoxy having a metal-containing material is injected into the opening side of the intermittent loop-shaped conductive thin film, and the injected epoxy is cured and connected to the loop-shaped conductive thin film. , it is possible to change the shape of a loop-shaped conductive thin film into a closed-loop shape.

In the process of bonding the sensor unit 400 and the lens unit 700, a conductive thin film having a metal-containing material and having a loop shape is disposed between the lens unit 700 and the sensor unit 400, and the conductive thin film is cured. By expanding and forming a closed loop shape, the lens unit 700 and the sensor unit 400 are bonded to the conductive thin film, and the lens cavity C1 is isolated. In this process, a heat dissipation path having more heat transfer efficiency and more effective than in the embodiment may be formed. On the other hand, when heat is applied to the conductive thin film having an intermittent loop shape to harden and expand the conductive thin film and bond it in a closed loop shape, the space between the loop-shaped conductive thin film and the sensor unit 400 and the lens unit 400 While the air expands, it can be discharged through intermittent parts of the loop shape, and after the closed loop shape is formed, the pressure inside the lens cavity (C1) is slightly higher than the vacuum of the embodiment, but the pressure is lower than atmospheric pressure. can Accordingly, the sensitivity of the sensor unit 400 to sense light can be improved compared to when the sensor cavity C1 is set to atmospheric pressure.

Hereinafter, a method of controlling heat by operating a sensor package module according to an embodiment of the present invention will be briefly described. First, a control signal is output to the sensor package module mounted in the device to operate the sensor unit 400 of the sensor package module. Accordingly, the sensor unit receives light emitted from the region of interest and generates an electrical signal. The generated electrical signal is processed through a signal path (S) and transmitted to the device. At this time, heat is generated in the sensor unit 400 due to the incidence of light. The generated heat may contaminate the lens unit 700 in the form of radiant energy through the sensor cavity C1. At this time, the junctions 800 and 800' of the heat dissipation path H according to the embodiment of the present invention and other embodiments quickly discharge heat from the lens unit 700 to the sensor unit 400, and the sensor unit 400 ) is discharged to the substrate unit 100 along the heat dissipation path H, thereby preventing the sensor unit 400 from being affected by heat. Therefore, even if the sensor package module is used for a long time, heat accumulation in the sensor cavity can be effectively prevented, and contamination by heat is prevented, so that the sensitivity of the sensor unit 400 to detect light is always maintained in an optimal state. can make it In addition, since the sensor cavity has a pressure lower than atmospheric pressure in embodiments of the present invention, there are few air particles capable of receiving and transferring heat in the sensor cavity (in the case of vacuum) or less than atmospheric pressure (between vacuum and atmospheric pressure). in the case of low pressure). Thus, contamination of the sensor unit 400 by heat can be more effectively prevented.

The above embodiments of the present invention are for explanation of the present invention and are not intended to limit the present invention. It should be noted that the configurations and methods disclosed in the above embodiments of the present invention may be combined and modified in various forms by combining or crossing each other, and variations thereof may also be considered within the scope of the present invention. That is, the present invention will be implemented in a variety of different forms within the scope of the claims and equivalent technical ideas, and various embodiments are possible within the scope of the technical idea of the present invention by those skilled in the art to which the present invention pertains. will be able to understand

100: board part 110: base material
120: through electrode 400: sensor unit
420: membrane 500: attachment
600: connection part 700: lens part
800: junction 900: molding

Claims (20)

board part;
a sensor unit laminated on one surface of the substrate unit;
a lens unit stacked on one surface of the sensor unit to form a lens cavity isolated from the outside between the sensor unit;
A sensor package module comprising: a bonding portion having a metal-containing material, disposed between the sensor unit and the lens unit, and bonding the sensor unit and the lens unit together. The method of claim 1,
The sensor package module of claim 1 , wherein the substrate unit has a through electrode for connecting the other surface opposite to one surface of the substrate unit to one surface of the substrate unit. The method of claim 1,
The sensor package module having a sensor element and an input/output pad electrically connected to the sensor element and connected to the substrate part by wire bonding on one surface of the sensor unit. The method of claim 3,
a connecting portion for connecting the input/output pad and the board through wire bonding;
A sensor package module comprising: an attachment part having a metal-containing material and attaching the other surface opposite to one surface of the sensor part to the substrate part. The method of claim 1,
A sensor package module comprising a; readout integrated circuit board portion bonded to the other surface of the substrate portion. The method of claim 1,
To seal the lens cavity,
The bonding portion includes a conductive bump formed on the sensor unit in a closed loop shape surrounding the lens cavity,
The lens unit includes a bonding pattern formed on the other surface facing the sensor unit so as to be bonded to the conductive bump. The method of claim 1,
The junction part, in order to seal the lens cavity, surrounds the circumference of the lens cavity and includes a conductive thin film formed in a closed loop shape between the other surface of the lens part and the sensor part. The method of any one of claims 1 to 7,
The substrate portion includes a plurality of through electrodes,
Some of the plurality of through electrodes form a signal path for transmitting an electrical signal,
The other through electrodes among the plurality of through electrodes form a heat dissipation path for dissipating heat through a path different from the signal path. The method of any one of claims 1 to 7,
The board part,
parent material;
a plurality of through electrodes formed to penetrate the base material;
a first wiring pattern formed on one surface of the base material, connected to some of the plurality of through electrodes, and connected to the sensor unit through wire bonding;
a second wiring pattern formed on the other surface opposite to one surface of the base material and connected to some of the through electrodes;
a third wiring pattern formed on one surface of the base material, connected to the remaining through electrodes among the plurality of through electrodes, and brought into thermal contact with the sensor unit; and
A sensor package module comprising: a fourth wiring pattern formed on the other surface of the base material and connected to the remaining through electrodes. The method of claim 9,
A heat dissipation path connecting the lens cavity and the other surface of the base material is formed by the junction part, the sensor part, the third wiring pattern, the remaining through electrodes, and the fourth wiring pattern,
A signal path connecting the sensor unit and the other surface of the base material is formed by the first wiring pattern, the partial through-electrode, and the second wiring pattern,
The signal path is separated from the heat dissipation path sensor package module. The method of any one of claims 1 to 8,
The sensor unit,
a body for forming a sensor cavity;
a membrane formed on one surface of the body to seal one side of the sensor cavity;
a sensor element formed on the membrane;
A sensor package module including an input/output pad formed on one surface of the body and electrically connected to the sensor element. The process of preparing the substrate portion;
Bonding the lower surface of the sensor unit on the substrate unit;
connecting a partial area of an upper surface of the sensor unit with a partial area of the substrate unit;
disposing a lens unit on the sensor unit;
A method of manufacturing a sensor package module comprising: bonding the sensor unit and the lens unit using a bonding unit having a metal-containing material. The method of claim 12,
The process of preparing the substrate part,
Forming a plurality of through electrodes to penetrate the base material;
forming first and second wiring patterns on one surface and the other surface of the base material to be connected to some of the plurality of through electrodes;
A method of manufacturing a sensor package module, comprising: forming third and fourth wiring patterns on one surface and the other surface of the base material so as to be connected to the remaining through electrodes except for the partial through electrodes. The method of claim 13,
The process of bonding the lower surface of the sensor unit on the substrate unit,
disposing the sensor unit on the substrate unit so as to overlap at least a portion of the third wiring pattern;
forming a bonding layer having a metal-containing material between the substrate and the sensor;
bonding the substrate part and the sensor part to the bonding layer;
and thermally connecting the sensor unit, the third wiring pattern, the remaining through electrodes, and the fourth wiring pattern by using the metal-containing material in the bonding layer. The method of claim 13,
The process of connecting a partial area of the upper surface of the sensor unit with a partial area of the substrate unit,
A process of connecting the first wiring pattern and the input/output terminals of the sensor unit by wire bonding to electrically connect the sensor unit, the wire, the first wiring pattern, the partial penetration electrode, and the second wiring pattern; A method for manufacturing a sensor package module. The method of claim 13,
The process of bonding the sensor unit and the lens unit,
A method of manufacturing a sensor package module comprising: forming a lens cavity between the lens unit and the sensor unit. The method of claim 16
The process of forming the lens cavity,
bringing an edge of the concave groove formed in the lens unit into contact with the sensor unit;
A method of manufacturing a sensor package module comprising: bonding an edge of the concave groove and the sensor unit to form a sealed lens cavity. The method of claim 17
The process of bonding the edge of the concave groove and the sensor unit,
contacting a bonding pattern formed on the lens unit and a conductive bump having a closed loop shape and having a metal-containing material formed on the sensor unit;
A method of manufacturing a sensor package module comprising: heat-treating and bonding a junction between the junction pattern and the conductive bump. The method of claim 17
The process of bonding the edge of the concave groove and the sensor unit,
disposing a conductive thin film having the metal-containing material and having an intermittent loop shape between the lens unit and the sensor unit;
Method of manufacturing a sensor package module comprising: curing and expanding the conductive thin film to bond it in a closed loop shape. The method of claim 18
The process of contacting the conductive bumps and the process of bonding by heat treatment are performed in a vacuum atmosphere.

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