A packaging structure and packaging method thereof
By integrating magnetic sensors, acceleration sensors and gyroscopes into one package, the problems of large packaging area and high cost in the prior art are solved, and a high integration and low cost packaging structure is achieved, and the application scope is expanded.
Patent Information
- Application Number
- CN202110956303.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-08-19
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2041-08-19
AI Technical Summary
Existing magnetic sensors, acceleration sensors and gyroscopes usually require separate flow sheets and assembled on the same substrate, resulting in large package area, high cost and low integration.
The magnetic sensor, acceleration sensor and gyroscope are integrated into one package, and a highly integrated package structure is formed through the bonding and plastic packaging process of semiconductor wafers, reducing packaging volume and cost.
It achieves high integration of products, shortens processing cycles and reduces costs, and expands application prospects.
Smart Images
Figure CN113629023B_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to the technical field of integrated sensors, and in particular to a packaging structure and a packaging method of an integrated magnetic sensor, an acceleration sensor and a gyroscope. [Background technology]
[0002] With the rapid development of Internet of Things technology, the application of sensors has gradually become popular, and magnetic sensors, accelerometers and gyroscopes are increasingly widely used in consumer, industrial and automotive electronics fields. However, these sensors with different functions are usually used as independent products, because the manufacturing processes of magnetic sensors and other sensors such as accelerometers and gyroscopes are different, and they usually need to be taped out separately and then assembled on the same substrate, which will take up more packaging area and cost.
[0003] Therefore, it is necessary to propose a technical solution to overcome the above problems. [Summary of the invention]
[0004] One of the purposes of the present invention is to provide a packaging structure and a packaging method thereof, which integrates a magnetic sensor, an acceleration sensor and a gyroscope into a package body, thereby making the product more integrated and reducing the processing cost.
[0005] According to one aspect of the present invention, the present invention provides a packaging structure, which includes: a first semiconductor wafer, a magnetic sensor, a first metal pad and a first redistribution layer connected to the first metal pad are arranged on the front side of the first semiconductor wafer, and a first cavity and a second cavity are arranged on the back side of the first semiconductor wafer, wherein the first redistribution layer is located below the first metal pad; a second semiconductor wafer, a second metal pad, an acceleration sensor and a gyroscope are arranged on the front side of the first semiconductor wafer, and the second semiconductor wafer is bonded to the back side of the first semiconductor wafer, wherein the second semiconductor wafer is located above the first semiconductor wafer, the front side of the second semiconductor wafer is opposite to the back side of the first semiconductor wafer, and the acceleration sensor and the gyroscope on the front side of the second semiconductor wafer are respectively opposite to the first cavity and the second cavity on the surface of the first semiconductor wafer.
[0006] According to another aspect of the present invention, the present invention provides a packaging method for a packaging structure, comprising: providing a first semiconductor wafer, the front side of which is provided with a magnetic sensor, a first metal pad and a first redistribution layer connected to the first metal pad, and the back side of which is provided with a first cavity and a second cavity, wherein the first redistribution layer is located below the first metal pad; providing a second semiconductor wafer, the front side of which is provided with a second metal pad, an acceleration sensor and a gyroscope; bonding the second semiconductor wafer to the back side of the first semiconductor wafer, after bonding, the second semiconductor wafer is located above the first semiconductor wafer, the front side of the second semiconductor wafer is opposite to the back side of the first semiconductor wafer, and the acceleration sensor and the gyroscope on the front side of the second semiconductor wafer are respectively opposite to the first cavity and the second cavity on the back side of the first semiconductor wafer.
[0007] Compared with the prior art, the present invention integrates a magnetic sensor, an acceleration sensor and a gyroscope into one package, which, on the one hand, shortens the product processing cycle and reduces the processing cost; on the other hand, the product has a higher degree of integration, reduces the package volume, and has a wider application prospect.
Brief Description of the Drawings
[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:
[0009] Figure 1 is a schematic longitudinal cross-sectional view of a packaging structure of an integrated magnetic sensor, an acceleration sensor and a gyroscope in one embodiment of the present invention;
[0010] Figure 2 A schematic flow chart of a packaging method for a packaging structure integrating a magnetic sensor, an acceleration sensor and a gyroscope in one embodiment of the present invention;
[0011] Figure 3-Figure 10 In one embodiment of the present invention Figure 2 The longitudinal cross-sectional views corresponding to the steps shown. [Specific implementation method]
[0012] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0013] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments. Unless otherwise specified, the words "connected", "connected", and "connected" herein that indicate electrical connection all refer to direct or indirect electrical connection.
[0014] Please refer to Figure 1 , which is a schematic longitudinal cross-sectional view of a packaging structure in one embodiment of the present invention, which integrates a magnetic sensor, an acceleration sensor and a gyroscope into one package. Figure 1 The packaging structure shown includes a first semiconductor wafer 1, a second semiconductor wafer 2, a substrate 4 and a plastic packaging material 5. After the semiconductor wafer-level packaging, the semiconductor wafer cutting step will be performed to form a plurality of independent packaging structures, i.e., independent chips. From the perspective of the semiconductor wafer before cutting, i.e., from the perspective of the semiconductor wafer level (i.e., wafer level), the first semiconductor wafer 1 and the second semiconductor wafer 2 are two independent semiconductor wafers. From the perspective of the semiconductor wafer after cutting, i.e., from the perspective of the chip level, the first semiconductor wafer 1 and the second semiconductor wafer 2 can be understood as chips of each semiconductor wafer.
[0015] The first semiconductor wafer 1 is a magnetic sensor wafer, and a magnetic sensor (including a structural circuit of the magnetic sensor and a driving circuit thereof) 101, a first metal pad 102 and a first rewiring layer 103 connected to the first metal pad 102 are arranged on the front side thereof, and a first cavity 104 and a second cavity 105 are arranged on the back side thereof, wherein the first rewiring layer 103 is located below the first metal pad 102; the first rewiring layer 103 is protected by a passivation layer.
[0016] The second semiconductor wafer 2 is an accelerometer and gyroscope integrated wafer, and a second metal pad 201, an acceleration sensor (including the structural circuit of the acceleration sensor and its driving circuit) 202 and a gyroscope (including the structural circuit of the gyroscope and its driving circuit) 203 are arranged on the front side thereof. The second semiconductor wafer 2 is bonded to the back side of the first semiconductor wafer 1, wherein the second semiconductor wafer 2 is located above the first semiconductor wafer 1, the front side of the second semiconductor wafer 2 is opposite to the back side of the first semiconductor wafer 1, and the acceleration sensor 202 and the gyroscope 203 on the front side of the second semiconductor wafer 2 are respectively opposite to the first cavity 104 and the second cavity 105 on the back side of the first semiconductor wafer 1.
[0017] In one embodiment, the bonding between the first semiconductor wafer 1 and the second semiconductor wafer 2 can be achieved by glue bonding, metal bonding or anodic bonding.
[0018] exist Figure 1 In the illustrated embodiment, a second rewiring layer 204 is provided on the back side of the bonded second semiconductor wafer 2 (or the side of the second semiconductor wafer 2 away from the first semiconductor wafer 1), which is led out by the second metal pad 201 and redistributed to the back side of the second semiconductor wafer 2, wherein the second metal pad 201 is led out by drilling holes on the second semiconductor wafer 2, which is realized by a through silicon via (TSV) process, specifically, the second metal pad 201 on the front side of the second semiconductor wafer 2 is led to the back side of the second semiconductor wafer 2 by a metal through-line penetrating the second semiconductor wafer 2 and the second rewiring layer 204, and is protected by a passivation layer. In another embodiment, the second metal pad 201 is led out by a slope metal rewiring process in the second semiconductor wafer 2.
[0019] A solder ball 106 is arranged on the first redistribution layer (103) on the front side of the first semiconductor wafer (1). The metal pads 102, 201 and the solder ball 106 can both be used as signal contacts.
[0020] The first semiconductor wafer 1 and the second semiconductor wafer 2 are bonded and stacked in sequence from the front side of the substrate 4 upwards, wherein the solder ball 106 on the front side of the first semiconductor wafer 1 is connected to the substrate 4 containing the circuit layer by a flip-chip process; the second redistribution layer (204) on the back side of the second semiconductor wafer (2) is connected to the substrate (4) containing the circuit layer by a pressure welding process using a welding wire 3, thereby integrating the first semiconductor wafer 1, the second semiconductor wafer 2 and the substrate 6 together.
[0021] Through the molding process, the integrated first semiconductor wafer 1 , the second semiconductor wafer 2 and the substrate 4 are molded with a molding compound 5 to form a final package.
[0022] Please refer to Figure 2 As shown, it is a schematic diagram of a packaging method of a packaging structure in one embodiment of the present invention; please refer to Figure 3-Figure 10 As shown, in one embodiment of the present invention, Figure 2 The longitudinal cross-sectional views corresponding to the steps shown. Figure 2 The packaging method of the packaging structure shown includes the following steps.
[0023] Step 210: Figure 3As shown, a first semiconductor wafer 1 is provided, which is a magnetic sensor wafer, and a magnetic sensor (including a structural circuit of the magnetic sensor and a driving circuit thereof) 101, a first metal pad 102 and a first rewiring layer 103 connected to the first metal pad 102 are arranged on the front side thereof, and a first cavity 104 and a second cavity 105 are arranged on the back side thereof, wherein the first rewiring layer 103 is located below the first metal pad 102; the first rewiring layer 103 is protected by a passivation layer.
[0024] Step 220: Figure 4 As shown, a second semiconductor wafer 2 is provided, which is an accelerometer and gyroscope integrated wafer, and a second metal pad 201, an acceleration sensor (including a structural circuit of the acceleration sensor and a driving circuit thereof) 202 and a gyroscope (including a structural circuit of the gyroscope and a driving circuit thereof) 203 are arranged on the front side thereof.
[0025] Step 230: Figure 5 As shown, the second semiconductor wafer 2 is bonded to the back side of the first semiconductor wafer 1. After bonding, the second semiconductor wafer 2 is located above the first semiconductor wafer 1, the front side of the second semiconductor wafer 2 is opposite to the back side of the first semiconductor wafer 1, and the acceleration sensor 202 and the gyroscope 203 on the front side of the second semiconductor wafer 2 are opposite to the first cavity 104 and the second cavity 105 on the back side of the first semiconductor wafer 1, respectively.
[0026] In one embodiment, the bonding between the first semiconductor wafer 1 and the second semiconductor wafer 2 can be achieved by glue bonding, metal bonding or anodic bonding.
[0027] Step 240: Figure 6 As shown, a second rewiring layer 204 is formed on the back side of the second semiconductor wafer 2 (or the side of the second semiconductor wafer 2 away from the first semiconductor wafer 1) after bonding, and the second rewiring layer 204 is led out from the second metal pad 201 and redistributed to the back side of the second semiconductor wafer 2. Figure 6 In the embodiment shown, the second metal pad 201 is led out by drilling holes on the second semiconductor wafer 2, which is achieved by a through-silicon via (TSV) process. Specifically, the second metal pad 201 on the front side of the second semiconductor wafer 2 is led to the back side of the second semiconductor wafer 2 through a metal through-line that penetrates the second semiconductor wafer 2 and a second rewiring layer 204, and is protected by a passivation layer. In another embodiment, the second metal pad 201 is led out by a slope metal rewiring process in the second semiconductor wafer 2.
[0028] Step 250: Figure 7 As shown, solder balls 106 are arranged on the first redistribution layer 103 on the front side of the first semiconductor wafer 1 after bonding. The metal pads 102, 201 and the solder balls 106 can all be used as signal contacts.
[0029] Step 260: Figure 8 As shown, the solder balls 106 on the back side of the first semiconductor wafer 1 are connected to the substrate 4 by a flip-chip process.
[0030] Step 270: Fig. 9 As shown, the second redistribution layer 204 on the back side of the second semiconductor wafer 2 is connected to the substrate 4 using bonding wires 3 through a pressure welding process.
[0031] Step 280: Fig.10 As shown, the first semiconductor wafer 1 , the second semiconductor wafer 2 and the substrate 4 integrated together are sealed with a sealing material 5 through a sealing process to form a final package.
[0032] In summary, the present invention can concentrate the magnetic sensor, acceleration sensor and gyroscope into one package, which can, on the one hand, make the product more integrated and have a wider range of applications; on the other hand, two semiconductor wafers can be taped out at the same time, and after the wafers are bonded, wafer-level packaging is first performed and then dicing is performed before flip-chip and bonding processes (i.e. chip bonding), thereby avoiding the increase in cost and extension of the processing cycle caused by taping out the wafers separately.
[0033] In the present invention, words such as “connect”, “connected”, “connected”, “connected”, etc. indicating electrical connection, if not otherwise specified, indicate direct or indirect electrical connection.
[0034] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the content disclosed in the present invention should be included in the protection scope recorded in the claims.
Claims
1. A packaging structure, characterized in that: It includes: A first semiconductor wafer (1), on the front side of which a magnetic sensor (101), a first metal pad (102) and a first rewiring layer (103) connected to the first metal pad (102) are arranged, and on the back side of which a first cavity (104) and a second cavity (105) are arranged, wherein the first rewiring layer (103) is located below the first metal pad (102); A second semiconductor wafer (2) is provided with a second metal pad (201), an acceleration sensor (202) and a gyroscope (203) on its front side, and the second semiconductor wafer (2) is bonded to the back side of the first semiconductor wafer (1), wherein the second semiconductor wafer (2) is located above the first semiconductor wafer, the front side of the second semiconductor wafer (2) is opposite to the back side of the first semiconductor wafer (1), and the acceleration sensor (202) and the gyroscope (203) on the front side of the second semiconductor wafer (2) are respectively opposite to the first cavity (104) and the second cavity (105) on the back side of the first semiconductor wafer (1).
2. The packaging structure according to claim 1, characterized in that: It also includes: A second redistribution layer (204) is led out from the second metal pad (201) and redistributed to the back side of the second semiconductor wafer (2).
3. The packaging structure according to claim 2, characterized in that: The second metal pad (201) is led out in the second semiconductor wafer (2) by a slope metal rewiring process; or The second metal pad (201) is led out by drilling a hole on the second semiconductor wafer (2), which is achieved by a through-hole process.
4. The packaging structure according to claim 2, characterized in that: It also includes: A solder ball (106) is arranged on the first redistribution layer (103) on the front side of the first semiconductor wafer (1).
5. The packaging structure according to claim 4, characterized in that: It also includes a substrate (4), The bonded first semiconductor wafer (1) and the second semiconductor wafer (2) are stacked in sequence from the front side of the substrate (4) upwards; Connecting the solder ball (106) on the front side of the first semiconductor wafer (1) to the substrate (4) through a flip-chip process; The second redistribution layer (204) on the back side of the second semiconductor wafer (2) is connected to the substrate (4) using a bonding wire (3) through a pressure welding process.
6. The packaging structure according to claim 5, characterized in that: It also includes: A molding compound (5) is used to mold the first semiconductor wafer (1), the second semiconductor wafer (2) and the substrate (4) which are integrated together.
7. A packaging method of a packaging structure, characterized in that: It includes: A first semiconductor wafer (1) is provided, wherein a magnetic sensor (101), a first metal pad (102) and a first rewiring layer (103) connected to the first metal pad (102) are arranged on the front side of the first semiconductor wafer (1), and a first cavity (104) and a second cavity (105) are arranged on the back side of the first semiconductor wafer (1), wherein the first rewiring layer (103) is located below the first metal pad (102); Providing a second semiconductor wafer (2), wherein a second metal pad (201), an acceleration sensor (202) and a gyroscope (203) are arranged on the front side of the second semiconductor wafer (2); The second semiconductor wafer (2) is bonded to the back side of the first semiconductor wafer (1). After bonding, the second semiconductor wafer (2) is located above the first semiconductor wafer (1), the front side of the second semiconductor wafer (2) is opposite to the back side of the first semiconductor wafer (1), and the acceleration sensor (202) and the gyroscope (203) on the front side of the second semiconductor wafer (2) are respectively opposite to the first cavity (104) and the second cavity (105) on the back side of the first semiconductor wafer (1).
8. The packaging method of the packaging structure according to claim 7, characterized in that: It includes: forming a second redistribution layer (204) on the back side of the second semiconductor wafer (2) after bonding, wherein the second redistribution layer (204) is led out from the second metal pad (201) and redistributed to the back side of the second semiconductor wafer (2); A solder ball (106) is arranged on the first redistribution layer (103) on the front side of the first semiconductor wafer (1) after bonding.
9. The packaging method of the packaging structure according to claim 8, characterized in that: The second metal pad (201) is led out in the second semiconductor wafer (2) by a slope metal rewiring process; or The second metal pad (201) is led out by drilling a hole on the second semiconductor wafer (2), which is achieved by a through-hole process.
10. The packaging method of the packaging structure according to claim 8, characterized in that: It also includes: Connecting the solder ball (106) on the back side of the first semiconductor wafer (1) to the substrate (4) through a flip-chip process; The second redistribution layer (204) on the back side of the second semiconductor wafer (2) is connected to the substrate (4) using a bonding wire (3) through a pressure welding process.
11. The packaging method of the packaging structure according to claim 10, characterized in that: It also includes: The first semiconductor wafer (1), the second semiconductor wafer (2) and the substrate (4) integrated together are plastic-sealed using a plastic-sealing material (5) through a plastic-sealing process to form a plastic-sealed body.