Piezoelectric chip preparation process using polymer auxiliary lead
Through the polymer-assisted lead process, the structural asymmetry caused by electrode extraction in the piezoelectric chip is solved, the device performance is ensured, and the chip symmetry and effective connection between electrode extraction is achieved.
Patent Information
- Application Number
- CN202311222079.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-20
- Publication Date
- 2024-12-13
AI Technical Summary
During the production process of piezoelectric chips, due to the electrode introduction problem of the PZT layer, the structural asymmetry is caused, which affects the performance of the device. When trying to form trenches by etching the surrounding area, the intermediate electrode cannot be drawn out, resulting in an isolated island.
Using polymer-assisted lead process, by growing metal and piezoelectric layers on the substrate and forming gaps through etching to separate the vibrating and fixing parts, the electrical connection lines are wrapped with polymer and extended into the gaps, ensuring that Symmetry and electrode lead out, and finally the polymer is removed to form a symmetrical structure.
It realizes solving the lead problem while maintaining chip symmetry, ensuring device performance, avoiding the formation of intermediate islands, and improving the structural symmetry and performance of the chip.
Smart Images
Figure CN119136637A_ABST
Abstract
Description
Technical Field
[0001] One or more embodiments of the present specification relate to the field of semiconductor process technology, and in particular, to a process for preparing a piezoelectric chip using polymer auxiliary leads. Background Art
[0002] During the production process of piezoelectric chips, the electrodes on the upper surface of the PZT need to be led out, so a bridge needs to be left in the PZT layer. However, this will make the structure asymmetric and affect the performance of the device. To ensure symmetry, if the surrounding area is cut out to form a groove, it will cause the problem that the electrodes on the isolated island in the middle cannot be led out.
[0003] In summary, the present application now proposes a piezoelectric chip preparation process using polymer auxiliary leads to solve the above-mentioned problems. Summary of the invention
[0004] The present invention aims to solve the problems raised in the background technology. The purpose of one or more embodiments of this specification is to propose a piezoelectric chip preparation process using polymer auxiliary leads, which solves the lead problem and ensures device performance while maintaining chip symmetry.
[0005] Based on the above purpose, one or more embodiments of the present specification provide a process for preparing a piezoelectric chip using a polymer auxiliary lead, comprising the following steps: preparing a substrate, the substrate having a relative front and back side; growing a metal layer and a piezoelectric layer on the front side of the substrate, the piezoelectric layer and the metal layer being spaced apart; etching the top metal layer to pattern the top metal layer to produce a gap, the gap causing the top metal layer to form a first vibration part and a pad from the inside to the outside; etching the piezoelectric layer to pattern the piezoelectric layer to produce a gap, the gap causing the piezoelectric layer to form a second vibration part and a fixed part corresponding to the first vibration part, which are independent of each other, from the inside to the outside; etching the exposed part of the lower metal layer due to the gap, exposing the front side area of the substrate; connecting the first vibration part of the second metal layer to the pad through an electrical connection line; growing a polymer for sealing the electrical connection line on a plane of the top metal layer away from the substrate, and extending it into the gap; etching the back side of the substrate to form a cavity on the back side of the substrate; and removing the polymer.
[0006] According to the process for preparing a piezoelectric chip using polymer auxiliary leads described in an embodiment of the present invention, the substrate is an SOI substrate.
[0007] According to the process for preparing a piezoelectric chip using polymer auxiliary leads described in an embodiment of the present invention, the substrate is a silicon substrate.
[0008] According to the process for preparing a piezoelectric chip using polymer auxiliary leads described in an embodiment of the present invention, the polymer includes one or a combination of polydimethylsiloxane, hydrogel, parelene, PI and silica gel.
[0009] According to the process for preparing a piezoelectric chip using polymer auxiliary leads described in an embodiment of the present invention, the electrical connection wires include gold wires.
[0010] According to the process for preparing a piezoelectric chip using polymer auxiliary leads described in an embodiment of the present invention, the polymer is dissolved by wet etching.
[0011] The beneficial effects of the present invention are described in detail below with reference to the embodiments and drawings of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In order to more clearly illustrate one or more embodiments of the present specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of the present specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0013] Figure 1 A schematic diagram of step S1 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention;
[0014] Figure 2 A schematic diagram of step S2 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention;
[0015] Figure 3 A schematic diagram of step S3 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention;
[0016] Figure 4 A schematic diagram of step S4 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention;
[0017] Figure 5 A schematic diagram of step S5 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention;
[0018] Figure 6 This is a schematic diagram of step S6 of a process for preparing a piezoelectric chip using polymer auxiliary leads according to an embodiment of the present invention.
[0019] In the figure numerals: 1. bottom silicon; 2. buried oxide layer; 3. top silicon; 4. first metal layer; 5. piezoelectric layer; 6. second metal layer; 7. electrical connection line; 8. polymer. DETAILED DESCRIPTION
[0020] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.
[0021] According to the following Figure 1-Figure 6 The following describes the process for preparing a piezoelectric chip using polymer auxiliary leads in an embodiment of the present invention.
[0022] The process for preparing a piezoelectric chip using a polymer auxiliary lead according to an embodiment of the present invention comprises the following steps:
[0023] S1, prepare a substrate, the substrate is an SOI substrate, the SOI substrate includes a top silicon 3 and a bottom silicon 1 connected to a buried oxide layer 2, grow a first metal layer 4 as a top electrode on a plane of the top silicon 3 away from the bottom silicon 1, grow a piezoelectric layer 5 on a plane of the first metal layer 4 away from the top silicon 3, and grow a second metal layer 6 as a bottom electrode on a side of the piezoelectric layer 5 away from the top silicon 3, such as Figure 1 Optionally, the substrate is a silicon substrate (not shown in the figure).
[0024] S2-1, etching the second metal layer 6 to form a gap in the second metal layer 6, wherein the gap divides the second metal layer 6 from inside to outside into mutually independent first vibration parts and pads. Optionally, the gap is annular.
[0025] S2-2, etching the piezoelectric layer 5 so that the piezoelectric layer 5 produces a gap that is the same as the second metal layer 6. The gap divides the piezoelectric layer 5 from the inside to the outside into a second vibration part and a fixed part that are independent of each other. The first vibration part is located on the surface of the second vibration part, and the cross-sectional area of the first vibration part is less than or equal to the cross-sectional area of the second vibration part. The pad is located on the surface of the fixed part.
[0026] S2-3, etching the first metal layer 4 exposed through the gap, so that the first metal layer 4 is patterned, and a part of the top silicon 3 is exposed, such as Figure 2 Optionally, the exposed top silicon 3 is etched to make it patterned (not shown in the figure).
[0027] S3, electrically connecting the first vibration part of the second metal layer 6 and the pad through the electrical connection line 7, such as Figure 3 Optionally, the electrical connection wire 7 is a gold wire.
[0028] S4, growing a polymer 8 on a plane of the second metal layer 6 away from the substrate, the polymer 8 wraps the electrical connection line 7 as a whole and extends into the gap generated by etching in step S2, such as Figure 4 Optionally, the polymer 8 includes one or a combination of polydimethylsiloxane, hydrogel, parelene, PI (polyamide) and silica gel.
[0029] S5, etching the bottom silicon 1 and buried oxide layer 2 of the substrate to form a cavity on the back side of the substrate, such as Figure 5 shown.
[0030] S6, removing the growing polymer 8, such as Figure 6 Optionally, wet etching is used to dissolve the grown polymer 8.
[0031] The present invention etches the piezoelectric structure on the substrate to form a patterned structure. The patterned structure will form an island in the middle due to the groove. Polymer auxiliary leads are used for wiring, and there is no need to set up a cantilever beam inside the groove. While solving the lead problem, the structure is made symmetrical to ensure device performance.
[0032] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.
Claims
1. A process for preparing a piezoelectric chip using a polymer auxiliary lead, characterized in that: The following steps are involved: preparing a substrate, the substrate having a front side and a back side opposite to each other; A metal layer (4, 6) and a piezoelectric layer (5) are grown on the front side of the substrate, and the piezoelectric layer (5) and the metal layer (4, 6) are arranged at intervals; The uppermost metal layer (6) is etched to pattern the uppermost metal layer (6) to produce a gap, and the gap causes the uppermost metal layer (6) to form a first vibration part and a pad from the inside to the outside; the piezoelectric layer (5) is etched to pattern the piezoelectric layer (5) to produce a gap, and the gap causes the piezoelectric layer (5) to form a second vibration part and a fixed part that are independent of each other and correspond to the first vibration part from the inside to the outside; Etching the portion of the lower metal layer (4) exposed by the gap, exposing a front surface area of the substrate; Connecting the first vibration part of the uppermost metal layer (6) to the pad via an electrical connection line (7); A polymer (8) for sealing the electrical connection line (7) is grown on the plane of the uppermost metal layer (6) away from the substrate, and extends to the gap between the piezoelectric layer (5) and the lower metal layer (4) exposed by etching; Etching the back side of the substrate to form a cavity on the back side of the substrate; The polymer (8) is removed.
2. The process for preparing a piezoelectric chip using polymer auxiliary leads according to claim 1, characterized in that: The substrate is an SOI substrate.
3. The process for preparing a piezoelectric chip using polymer auxiliary leads according to claim 1, characterized in that: The substrate is a silicon substrate.
4. The process for preparing a piezoelectric chip using polymer auxiliary leads according to claim 1, characterized in that: The polymer (8) includes one or a combination of polydimethylsiloxane, hydrogel, parelene, PI and silica gel.
5. The process for preparing a piezoelectric chip using polymer auxiliary leads according to claim 1, characterized in that: The electrical connection wire (7) comprises a gold wire.
6. The process for preparing a piezoelectric chip using polymer auxiliary leads according to claim 1, characterized in that: The polymer (8) is dissolved by wet etching.