CN119001144A - Double-range acceleration sensor structure and manufacturing method - Google Patents
Double-range acceleration sensor structure and manufacturing method Download PDFInfo
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- CN119001144A CN119001144A CN202310563736.9A CN202310563736A CN119001144A CN 119001144 A CN119001144 A CN 119001144A CN 202310563736 A CN202310563736 A CN 202310563736A CN 119001144 A CN119001144 A CN 119001144A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/12—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P1/00—Details of instruments
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Abstract
本发明提供一种双量程加速度传感器结构及制作方法，该方法包括：提供衬底；于衬底背面形成第一沟槽，于衬底正面形成多个压敏电阻；于衬底的正面形成介质层，介质层中设置有开口显露压敏电阻；于衬底内部选择性腐蚀出基于悬臂梁结构的高量程加速度传感器；于衬底正面形成金属层，金属层还延伸入开口中与压敏电阻电连接；于第一沟槽中形成预设深度的第五沟槽，于衬底的正面形成第六沟槽，第六沟槽与第五沟槽在垂直方向上相对应，且第六沟槽和第五沟槽连通。本发明的双量程加速度传感器结构及制作方法中，通过将低量程加速度传感器和高量程加速度传感器在单芯片上一体化集成，具有高灵敏、高频响、高抗过载、低成本、微型化的优点。
The present invention provides a dual-range acceleration sensor structure and a manufacturing method, the method comprising: providing a substrate; forming a first groove on the back of the substrate, forming a plurality of piezoresistors on the front of the substrate; forming a dielectric layer on the front of the substrate, and providing an opening in the dielectric layer to expose the piezoresistors; selectively etching a high-range acceleration sensor based on a cantilever beam structure inside the substrate; forming a metal layer on the front of the substrate, and the metal layer also extends into the opening to be electrically connected to the piezoresistors; forming a fifth groove of a preset depth in the first groove, and forming a sixth groove on the front of the substrate, the sixth groove corresponds to the fifth groove in the vertical direction, and the sixth groove is connected to the fifth groove. In the dual-range acceleration sensor structure and the manufacturing method of the present invention, by integrating the low-range acceleration sensor and the high-range acceleration sensor on a single chip, it has the advantages of high sensitivity, high frequency response, high overload resistance, low cost, and miniaturization.
Description
Technical Field
The invention belongs to the technical field of sensors, and relates to a dual-range acceleration sensor structure and a manufacturing method thereof.
Background
With the development of micro-mechanical system (MEMS) sensor technology, various MEMS sensors are attracting attention, wherein a silicon-based acceleration sensor is used as one of the hottest devices in the field of inertial sensors, and has important application backgrounds in the fields of aerospace, military fuzes, impact measurement, wearable devices, automobile electronics and the like. In order to truly reproduce the details of acceleration signals in the processes of collision, take-off, penetration and the like, the signal distortion is reduced as much as possible, and the acceleration sensor not only has high overload resistance and enough sensitivity, but also has higher resonant frequency and working bandwidth.
The piezoresistive acceleration sensor works on the principle that the mechanical strain caused by the acceleration force causes the resistivity of the piezoelectric material to change by utilizing the piezoresistive effect of the semiconductor, and the change is converted into a measurable signal output through a proper circuit to determine the acceleration. At present, the detection core component of the piezoresistive acceleration sensor mainly comprises a suspension type mechanical sensitive structure and a detection resistor, and is manufactured by utilizing a MEMS double-sided silicon micromachining process. Dong Jian et al, the Shanghai microsystem and information technology institute in 2002, fabricated a high impact accelerometer with a lateral deflection cantilever structure and piezoresistive sensing scheme using a double-sided silicon micromachining process, which can be used for the measuring range [J.Dong,X.Li,Y.Wang,at al.Silicon micromachined high-shock accelerometers with a curved-surface-application structure for over-rang stop protection and free-mode-resonance depression,J.Micromech.Microeng.2002,12(6):742-746], of tens of thousands of gravities, but has the following disadvantages: a. the back side corrosion of the (100) silicon chip is performed to form an inclined side wall, so that a large area is occupied, the processed chip is large in size and difficult to integrate; b. in the manufacturing process of the sensitive structure cantilever beam of the acceleration sensor, a great amount of time is required to use KOH solution to thin a silicon wafer with large area and large depth to the thickness of the expected structure beam, so that the production period is prolonged, and the manufacturing cost is increased; c. the gap between the cantilever beam and the substrate of the sensor using double-sided micromachining is large, and the air film damping is insufficient in the direction perpendicular to the sensitive direction to suppress parasitic signal interference caused by structural resonance, so that the sensitivity of the sensor is limited. The advanced single-silicon-wafer single-sided silicon micromachining technology is adopted by Wang Guchou et al of the Shanghai microsystem and information technology institute in 2012, so that the multifunctional composite sensor chip [J.C.Wang,X.Y.Xia,and X.X.Li.Monolithic Integration of Pressure Plus Acceleration Composite TPMS Sensors With a Single-Sided Micromachining Technology,Journal of Microelectromechanical Systems,vol.21,no.2,pp.284-293,Apr 2012], with single-chip integrated pressure and acceleration detection functions is manufactured, the sensitivity of the accelerometer is improved by utilizing the copper electroplating of the mass block, and two sensing elements are well integrated into a very small chip by virtue of the single-silicon-wafer single-sided silicon micromachining technology, so that the cost is reduced, but the sensor is limited by the structural design of an acceleration sensor, the frequency response of the sensor is not high, and the high overload resistance is limited. In order to further improve the sensitivity and frequency response of the device, korea university Taeyup Kim et al propose a method [Kim T,Jang S,Chang B,at al.A New Simple Fabrication Method for Silicon Nanowire-Based Accelerometers.20th International Conference on Solid-State Sensors,Actuators and Microsystems&Eurosensors XXXIII(TRANSDUCERS&EUROSENSORS XXXIII),2019,pp:1949～1952], for manufacturing a piezoresistive acceleration sensor using silicon nanowires, in which the resistivity of the sensor is greatly changed with the change of acceleration, and the chip size is very small, but the manufacturing difficulty of the silicon nanowires is high, which affects the yield of the sensor chip, and the overload resistance of the manufactured acceleration sensor is also required to be improved.
With the continuous development of MEMS technology, the structure of the acceleration sensor is becoming more and more diversified, and is being developed towards miniaturization, integration, high performance and low cost, but there is still a shortage such as frequency response, overload resistance and process cost, and a large lifting space. Therefore, the development of a dual-range acceleration sensor structure and a preparation method thereof are necessary.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention is directed to a dual-range acceleration sensor structure and a manufacturing method thereof, which are used for solving the problems of low frequency response, poor overload resistance, high process cost and the like of the acceleration sensor in the prior art.
To achieve the above and other related objects, the present invention provides a method for manufacturing a dual-range acceleration sensor structure, comprising the following steps:
providing a substrate, wherein the substrate comprises a front surface and a back surface which are oppositely arranged, and the substrate is divided into a low-range area and a high-range area;
Forming a first groove on the back surface of the substrate, wherein the first groove is positioned in the low-range area, and forming a plurality of piezoresistors on the front surface of the substrate, wherein at least one part of the piezoresistors are positioned in the low-range area, and at least one part of the piezoresistors are positioned in the high-range area;
forming a dielectric layer on the front surface of the substrate, and forming an opening at a preset position of the dielectric layer, wherein the opening exposes the piezoresistor;
Forming a second groove on the front surface of the substrate, and forming a resist layer on the side wall of the second groove, wherein the second groove is positioned in the high-range area;
Forming a third groove with a preset depth in the substrate based on the second groove, and forming a fourth groove which is laterally expanded in the substrate based on the third groove;
forming a metal layer on the dielectric layer, wherein the metal layer also extends into the opening and is electrically connected with the piezoresistor;
forming a fifth groove with a preset depth in the first groove;
and forming a sixth groove on the front surface of the substrate, wherein the sixth groove corresponds to the fifth groove in the vertical direction, and the sixth groove is communicated with the fifth groove.
Optionally, the substrate comprises a (111) monocrystalline silicon wafer, the second trenches are arranged along <110> and <211> crystal directions, and the fifth trenches are arranged along <110> and <211> crystal directions.
Optionally, before forming the sixth trench, a step of providing a support base and bonding the back surface of the substrate to the support base is further included.
Optionally, the step of forming the etching resist layer on the sidewall of the second trench includes:
Forming the etching resisting layer on the side wall and the bottom of the second groove by adopting a vapor deposition method;
And removing the etching resisting layer at the bottom of the second groove by adopting an etching method, and reserving the etching resisting layer on the side wall of the second groove.
Optionally, the first groove is used for a movable gap of a low range acceleration sensor, and the depth of the first groove is not more than 5 micrometers; the fourth groove is used for a movable gap of the high-range acceleration sensor, and the depth of the fourth groove is not less than 5 micrometers.
Optionally, the etch stop layer comprises a stacked silicon nitride layer and an ethyl orthosilicate passivation layer.
Optionally, before forming the second trench, a step of forming a mask layer on the front surface of the substrate, where the mask layer includes a stacked ethyl orthosilicate passivation layer, a silicon nitride layer, and an ethyl orthosilicate passivation layer.
The invention also provides a dual-range acceleration sensor structure, which comprises:
the device comprises a substrate, wherein the substrate comprises a front surface and a back surface which are oppositely arranged, and the substrate is divided into a low-range area and a high-range area;
the first groove is positioned on the back surface of the substrate and is positioned in the low-range area;
A plurality of piezoresistors positioned on the front surface of the substrate, wherein at least a part of the piezoresistors are positioned in the low-range area, and at least a part of the piezoresistors are positioned in the high-range area;
the dielectric layer is positioned on the front surface of the substrate, an opening is arranged at a preset position of the dielectric layer, and the opening exposes the piezoresistor;
The second groove is positioned on the front surface of the substrate and is positioned in the high-range area;
A third groove positioned below the second groove and communicated with the second groove;
The fourth groove is positioned at the side edge of the third groove and is communicated with the third groove;
the metal layer is positioned above the dielectric layer, and is filled in the opening and is electrically connected with the piezoresistor;
a fifth trench located in the first trench;
And the sixth groove is positioned on the front surface of the substrate, corresponds to the fifth groove in the vertical direction and is communicated with the fifth groove.
Optionally, the substrate comprises a (111) monocrystalline silicon wafer, the second trenches are arranged along <110> and <211> crystal directions, and the fifth trenches are arranged along <110> and <211> crystal directions.
Optionally, a support base is also included, the support base being located on the back side of the substrate and bonded to the substrate.
As described above, in the dual-range acceleration sensor structure and the manufacturing method of the dual-range acceleration sensor structure, the low-range acceleration sensor and the high-range acceleration sensor are integrated on the single chip, so that the dual-range acceleration sensor structure has the advantages of high sensitivity, high frequency response, high overload resistance, low cost and miniaturization.
Drawings
Fig. 1 is a flow chart of a method for manufacturing a dual-range acceleration sensor structure according to the present invention.
Fig. 2 shows a schematic view of a substrate provided in the present invention.
FIG. 3 is a schematic diagram showing the formation of a first trench on the back side of a substrate and the formation of a varistor on the front side of the substrate according to the present invention.
Fig. 4 is a schematic diagram showing that a dielectric layer is formed on the front surface of a substrate and an opening is formed in the dielectric layer in the present invention.
Fig. 5 is a schematic diagram illustrating a mask layer formed on the front surface of a substrate according to the present invention.
Fig. 6 is a schematic view of forming a second trench on the front surface of the substrate in the present invention.
Fig. 7 is a schematic view illustrating forming a resist layer on a sidewall of a second trench according to the present invention.
Fig. 8 is a schematic view of forming a third trench under the second trench in the present invention.
Fig. 9 is a schematic view illustrating forming a fourth trench on a side of the third trench in the present invention.
FIG. 10 is a schematic diagram of a metal layer formed over a dielectric layer according to the present invention.
Fig. 11 is a schematic view illustrating forming a fifth trench in the first trench in the present invention.
FIG. 12 is a schematic view of a back side bonding support base of a substrate according to the present invention.
Fig. 13 is a schematic view showing a sixth trench formed on the front surface of the substrate in the present invention.
Fig. 14 is a perspective view showing the structure of the dual-range acceleration sensor of the present invention.
Fig. 15 shows a top view of the low range acceleration sensor according to the present invention.
Fig. 16 is a top view of the high range acceleration sensor of the present invention.
Description of element reference numerals
1. Substrate and method for manufacturing the same
101. Low range region
102. High range area
103. Lower thermal oxide layer
104. Upper thermal oxide layer
2. First groove
3. Piezoresistor
4. Dielectric layer
4A lower dielectric layer
5. An opening
6. Mask layer
6A lower mask layer
7. Second groove
8. Etch-resistant layer
8A lower etch stop layer
9. Third groove
10. Fourth groove
11. Metal layer
12. Fifth groove
13. Support substrate
14. Sixth groove
15. Low range acceleration sensor
1501. Low range acceleration sensor mass block
1502. Low range acceleration sensor detection beam
1503. Cantilever beam of low-range acceleration sensor
1504. Low range acceleration sensor movable gap
16. High-range acceleration sensor
1601. Cantilever beam of high-range acceleration sensor
1602. Movable gap of high-range acceleration sensor
S1 to S8 steps
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
Please refer to fig. 1 to 16. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
The embodiment provides a method for manufacturing a dual-range acceleration sensor structure, referring to fig. 1, shown as a process flow chart of the method, comprising the following steps:
S1: providing a substrate, wherein the substrate comprises a front surface and a back surface which are oppositely arranged, and the substrate is divided into a low-range area and a high-range area;
s2: forming a first groove on the back surface of the substrate, wherein the first groove is positioned in the low-range area, and forming a plurality of piezoresistors on the front surface of the substrate, wherein at least one part of the piezoresistors are positioned in the low-range area, and at least one part of the piezoresistors are positioned in the high-range area;
s3: forming a dielectric layer on the front surface of the substrate, and forming an opening at a preset position of the dielectric layer, wherein the opening exposes the piezoresistor;
S4: forming a second groove on the front surface of the substrate, and forming a resist layer on the side wall of the second groove, wherein the second groove is positioned in the high-range area;
s5: forming a third groove with a preset depth in the substrate based on the second groove, and forming a fourth groove which is laterally expanded in the substrate based on the third groove;
S6: forming a metal layer on the dielectric layer, wherein the metal layer is filled into the opening and is electrically connected with the piezoresistor;
S7: forming a fifth groove with a preset depth in the first groove;
s8: and forming a sixth groove on the front surface of the substrate, wherein the sixth groove corresponds to the fifth groove in the vertical direction, and the sixth groove is communicated with the fifth groove.
First, referring to fig. 2, step S1 is performed: a substrate 1 is provided, the substrate 1 comprises a front surface and a back surface which are oppositely arranged, wherein the substrate 1 is divided into a low range area 101 and a high range area 102.
By way of example, the substrate 1 comprises a silicon substrate, a germanium substrate, a silicon germanium substrate or any other suitable semiconductor substrate. Specifically, in this embodiment, the substrate 1 is a (111) single crystal silicon wafer.
As an example, the low-range area 101 is used for subsequent processing of the low-range acceleration sensor, and the high-range area 102 is used for subsequent processing of the high-range acceleration sensor.
Next, referring to fig. 3, step S2 is performed: a first trench 2 is formed in the back surface of the substrate 1, the first trench 2 is located in the low-range region 102, and a plurality of piezoresistors 3 are formed in the front surface of the substrate 1, wherein at least a portion of the piezoresistors 3 are located in the low-range region 101, and at least a portion of the piezoresistors 3 are located in the high-range region 102.
As an example, before forming the first trench 2, the method further includes a step of forming a lower thermal oxide layer 103 on the back surface of the substrate 1 and forming an upper thermal oxide layer 104 on the front surface of the substrate 1; and patterning the lower oxide layer 103, and etching the substrate 1 based on the patterned lower oxide layer 103 to form the first trench 2; the upper oxide layer 104 is patterned, and ion implantation diffusion is performed based on the patterned upper oxide layer 104 to form the varistor 3.
As an example, the substrate 1 is etched using a silicon Deep Reactive Ion Etching (DRIE) method to form the first trench 2, and the depth of the first trench 2 is not more than 5 μm as a movable gap of the low-range acceleration sensor in the Z-axis direction.
As an example, in the process of forming the varistor 3, the implanted ions include boron ions, and the boron ions are implanted and then subjected to a high-temperature treatment, which is beneficial to the diffusion of the boron ions on the one hand and the repair of the damage of the ion implantation to the crystal lattice on the other hand.
As an example, after forming the first trench 2 and the varistor 3, the method further includes a step of removing the lower oxide layer 103 and the upper oxide layer 104.
Next, referring to fig. 4, step S3 is performed: a dielectric layer 4 is formed on the front surface of the substrate 1, an opening 5 is formed at a preset position of the dielectric layer 4, and the opening 5 exposes the piezoresistor 3.
By way of example, the dielectric layer 4 comprises a low stress silicon nitride layer formed by Low Pressure Chemical Vapor Deposition (LPCVD) or other suitable method; and, the method further comprises the step of forming a lower dielectric layer 4a on the back surface of the substrate 1 to balance the front surface and back surface stresses of the substrate 1.
As an example, the opening 5 is formed in the dielectric layer 4 by etching, and the opening 5 is used for electrode extraction of the subsequent piezoresistor 3.
As an example, referring to fig. 5, after the opening 5 is formed, a step of forming a mask layer 6 above the dielectric layer 4 is further included, where the mask layer 6 is used as a mask for subsequent front processing, and the mask layer 6 includes a stacked tetraethyl orthosilicate (TEOS) passivation layer, a low stress silicon nitride layer, and a TEOS passivation layer, where the TEOS passivation layer is a compressive stress film, and the silicon nitride layer is a tensile stress film, and stress of the mask layer 6 is reduced by the stacked TEOS passivation layer, the low stress silicon nitride layer, and the TEOS passivation layer; and, the method further comprises the step of forming a lower mask layer 6a on the back surface of the substrate 1 to balance the front surface and back surface stresses of the substrate 1.
Next, referring to fig. 6 to 7, step S4 is performed: a second trench 7 is formed on the front surface of the substrate 1, and a resist layer 8 is formed on the sidewall of the second trench 7, wherein the second trench 7 is located in the high-range region 102.
As an example, as shown in fig. 6, the mask layer 6 is patterned, and the substrate 1 is etched by using a DRIE method based on the patterned mask layer 6 to form the second trench 7, wherein the etching of the substrate 1 further includes etching the dielectric layer 4.
As an example, the second grooves 7 are arranged along the <110> and <211> crystal directions, and the second grooves 7 are used for the movable gap (see the following fig. 16) of the high-range acceleration sensor, wherein the depth of the second grooves 7 is the thickness of the cantilever beam of the high-range acceleration sensor.
As an example, as shown in fig. 7, the etch-stop layer 8 is formed on the sidewall of the second trench 7, where the etch-stop layer 8 is used to protect the sidewall of the second trench 7, and the etch-stop layer 8 includes a low stress silicon nitride and a TEOS passivation layer; specifically, the step of forming the etching resist layer 8 on the sidewall of the second trench 7 includes:
firstly, depositing a low-stress silicon nitride layer and a TEOS passivation layer on the side wall and the bottom of the second groove 7 in sequence by adopting an LPCVD method;
And (II) removing the low-stress silicon nitride layer and the TEOS passivation layer at the bottom of the second groove 7, and retaining the low-stress silicon nitride layer and the TEOS passivation layer on the side wall of the second groove 7.
Next, referring to fig. 8 to 9, step S5 is performed: a third trench 9 of a preset depth is formed in the substrate 1 based on the second trench 7, and a fourth trench 10 extending laterally is formed in the substrate 1 based on the third trench 9.
As an example, as shown in fig. 8, the substrate 1 is etched continuously along the bottom of the second trench 7 by using a DRIE method, so as to form the third trench 9 with a preset depth, where the depth of the third trench 9 is the movable gap depth of the high range acceleration sensor in the Z-axis direction.
As an example, as shown in fig. 9, based on the third trench 9, the substrate 1 is laterally wet etched with KOH or TMAH etching solution to form the fourth trench 10, the fourth trench 10 being used for a movable gap of a high range acceleration sensor in the Z-axis direction; the second groove 7 and the fourth groove 10 define a cantilever beam structure of the high-range acceleration sensor.
Next, referring to fig. 10, step S6 is performed: a metal layer 11 is formed on the dielectric layer 4, and the metal layer 11 is filled into the opening 5 and electrically connected with the piezoresistor 3.
As an example, before forming the metal layer 11, the method further includes a step of removing the mask layer 6, after removing the mask layer 6, a sputtering method is used to form metal above the dielectric layer 4 and pattern the metal layer 11, where the metal layer 11 is used for metal lead interconnection and bonding pads.
Next, referring to fig. 11, step S7 is performed: a fifth trench 12 of a predetermined depth is formed in the first trench 2.
As an example, the lower mask layer 6a located on the back surface of the substrate 1 is patterned, and the fifth trench 12 is formed by etching the substrate 1 using a DRIE method based on the patterned lower mask layer 6 a.
As an example, the fifth groove 12 is a deep groove arranged along the <110> and <211> crystal directions, the fifth groove 12 defines a mass, a cantilever, and a detection beam structure of the low range acceleration sensor (see subsequent fig. 15), and the fifth groove 12 is used for a movable gap of the low range acceleration sensor.
As an example, after the fifth trench 12 is formed, the lower mask layer 6a and the lower dielectric layer 4a on the back surface side of the substrate 1 are removed by etching.
Next, referring to fig. 12 to 13, step S8 is performed: a sixth trench 14 is formed in the front surface of the substrate 1, the sixth trench 14 corresponds to the fifth trench 12 in the vertical direction, and the sixth trench 14 communicates with the fifth trench 12.
As an example, referring to fig. 12, before forming the sixth trench 14, a step of providing a support base 13, and bonding the back surface of the substrate 1 to the support base 13, wherein the support base 13 is used for a support structure of a sensor frame; specifically, in this embodiment, the support base 13 is glass, and the back surface of the substrate 1 and the glass are bonded by anodic electrostatic bonding.
As an example, referring to fig. 13, the substrate 1 is etched by using a DRIE method to form the sixth trench 14.
To this end, referring to fig. 13 and 14, a dual-range acceleration sensor structure is shown as a cross-sectional view and a perspective view of the dual-range acceleration sensor structure, where the dual-range acceleration sensor structure includes a substrate 1, a first trench 2, a plurality of piezoresistors 3, a dielectric layer 4, a second trench 7, a third trench 9, a fourth trench 10, a metal layer 11, a fifth trench 12 and a sixth trench 14, where the substrate 1 includes a front surface and a back surface that are oppositely disposed, and the substrate 1 is divided into a low-range area 101 and a high-range area 102; the first trench 2 is located on the back surface of the substrate 1, and the first trench 2 is located in the low-range region 101; the piezoresistor 3 is positioned on the front surface of the substrate 1, at least one part of the piezoresistor 3 is positioned in the low-range area 101, and at least one part of the piezoresistor 3 is positioned in the high-range area 102; the dielectric layer 4 is positioned on the front surface of the substrate 1, an opening 5 is arranged at a preset position of the dielectric layer 4, and the opening 5 exposes the piezoresistor 3; the second trench 7 is located on the front surface of the substrate 1, and the second trench 7 is located in the high-range region 102; the third groove 9 is positioned below the second groove 7 and is communicated with the second groove 7; the fourth groove 10 is located at the side of the third groove 9 and is communicated with the third groove 9; the metal layer 11 is positioned above the dielectric layer 4, and the metal layer 11 is filled in the opening 5 and is electrically connected with the piezoresistor 3; the fifth groove 12 is located in the first groove 2; the sixth trench 14 is located on the front surface of the substrate 1, the sixth trench 14 corresponds to the fifth trench 15 in the vertical direction, and the sixth trench 14 and the fifth trench 12 communicate.
As an example, the first groove 2 is used for a movable gap of the low range acceleration sensor 15 in the Z direction, and the fifth groove 12 and the sixth groove 14 are used for movable gaps of the low range acceleration sensor 15 in the X and Y directions; referring to fig. 15, a top view of a low range acceleration sensor 15 is shown, including a low range acceleration sensor mass 1501, a low range acceleration sensor detecting beam 1502 and a low range acceleration sensor cantilever beam 1503, where the low range acceleration sensor mass 1501 includes a mass body and a mass foot protruding from the mass body, the low range acceleration sensor detecting beam 1502 is a straight-up and straight-down detecting beam, the low range acceleration sensor detecting beam 1502 is located at the top end of the mass foot and is connected with the mass foot, the low range acceleration sensor cantilever beam 1503 is connected with the low range acceleration sensor mass 1501 to provide support for the low range acceleration sensor mass 1501, and a low range acceleration sensor movable gap 1504 is provided around the low range acceleration sensor mass 1501, which has the following working principle: the low-range acceleration sensor mass 1501 swings in the low-range acceleration sensor movable gap 1504 under the action of acceleration force, so that the low-range acceleration sensor detection beam 1502 is mechanically strained, the resistivity of the piezoresistor 3 is changed, and the acceleration is determined by the change of the resistivity.
As an example, in this embodiment, one of the low range acceleration sensor mass 1501 is provided with two of the mass feet, two of the mass feet correspond to two of the low range acceleration sensor detecting beams 1502, and in other examples, one of the low range acceleration sensor mass 1501 may be provided with less than two or more than two of the low range acceleration sensor detecting beams 1502, not limited to this embodiment.
As an example, the fourth groove 10 is used for a movable gap of the high-range acceleration sensor 16 in the Z direction, the second groove 7 is used for a movable gap of the high-range acceleration sensor 16 in the X direction and the Y direction, referring to fig. 16, a top view of the high-range acceleration sensor 16 is shown, including a high-range acceleration sensor cantilever 1601, and high-range acceleration sensor movable gaps 1602 are provided around the high-range acceleration sensor cantilever 1601, and the working principle thereof is that: the cantilever 1601 of the high-range acceleration sensor swings in the movable gap 1602 of the high-range acceleration sensor under the action of the acceleration force, so that a region where the cantilever 1601 of the high-range acceleration sensor contacts with the piezoresistor 3 is strained, and further the resistivity of the piezoresistor 3 is changed, and the acceleration is determined by the change of the resistivity.
As an example, the low-range acceleration sensor 15 measures an acceleration range of 10E 1-10E 3 (m/s 2), and the high-range acceleration sensor 16 measures an acceleration range of 10E 3-10E 5 (m/s 2), and the dual-range acceleration sensor is integrated on a single chip, so that the dual-range acceleration sensor has the advantages of high sensitivity, high frequency response, high overload resistance, low cost and miniaturization.
In summary, in the dual-range acceleration sensor structure and the manufacturing method of the invention, the low-range acceleration sensor and the high-range acceleration sensor are integrated on the single chip, so that the dual-range acceleration sensor structure has the advantages of high sensitivity, high frequency response, high overload resistance, low cost and miniaturization. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (10)
1. The manufacturing method of the double-range acceleration sensor structure is characterized by comprising the following steps of:
providing a substrate, wherein the substrate comprises a front surface and a back surface which are oppositely arranged, and the substrate is divided into a low-range area and a high-range area;
Forming a first groove on the back surface of the substrate, wherein the first groove is positioned in the low-range area, and forming a plurality of piezoresistors on the front surface of the substrate, wherein at least one part of the piezoresistors are positioned in the low-range area, and at least one part of the piezoresistors are positioned in the high-range area;
forming a dielectric layer on the front surface of the substrate, and forming an opening at a preset position of the dielectric layer, wherein the opening exposes the piezoresistor;
Forming a second groove on the front surface of the substrate, and forming a resist layer on the side wall of the second groove, wherein the second groove is positioned in the high-range area;
Forming a third groove with a preset depth in the substrate based on the second groove, and forming a fourth groove which is laterally expanded in the substrate based on the third groove;
forming a metal layer on the dielectric layer, wherein the metal layer is filled into the opening and is electrically connected with the piezoresistor;
forming a fifth groove with a preset depth in the first groove;
and forming a sixth groove on the front surface of the substrate, wherein the sixth groove corresponds to the fifth groove in the vertical direction, and the sixth groove is communicated with the fifth groove.
2. The method for manufacturing the dual-range acceleration sensor structure according to claim 1, characterized in that: the substrate comprises a (111) monocrystalline silicon wafer, the second trenches are arranged along <110> and <211> crystal directions, and the fifth trenches are arranged along <110> and <211> crystal directions.
3. The method for manufacturing the dual-range acceleration sensor structure according to claim 1, characterized in that: the method further includes the step of providing a support base and bonding the back surface of the substrate to the support base prior to forming the sixth trench.
4. The method of fabricating a dual range acceleration sensor structure according to claim 1, characterized in, that the step of forming the etch stop layer on the sidewall of the second trench comprises:
Forming the etching resisting layer on the side wall and the bottom of the second groove by adopting a vapor deposition method;
And removing the etching resisting layer at the bottom of the second groove by adopting an etching method, and reserving the etching resisting layer on the side wall of the second groove.
5. The method for manufacturing the dual-range acceleration sensor structure according to claim 1, characterized in that: the first groove is used for a movable gap of the low-range acceleration sensor, and the depth of the first groove is not more than 5 micrometers; the fourth groove is used for a movable gap of the high-range acceleration sensor, and the depth of the fourth groove is not less than 5 micrometers.
6. The method for manufacturing the dual-range acceleration sensor structure according to claim 1, characterized in that: the etch-resistant layer comprises a laminated silicon nitride layer and an ethyl orthosilicate passivation layer.
7. The method for manufacturing the dual-range acceleration sensor structure according to claim 1, characterized in that: and before forming the second groove, forming a mask layer on the front surface of the substrate, wherein the mask layer comprises a laminated tetraethoxysilane passivation layer, a silicon nitride layer and a tetraethoxysilane passivation layer.
8. A dual range acceleration sensor structure, comprising:
the device comprises a substrate, wherein the substrate comprises a front surface and a back surface which are oppositely arranged, and the substrate is divided into a low-range area and a high-range area;
the first groove is positioned on the back surface of the substrate and is positioned in the low-range area;
A plurality of piezoresistors positioned on the front surface of the substrate, wherein at least a part of the piezoresistors are positioned in the low-range area, and at least a part of the piezoresistors are positioned in the high-range area;
the dielectric layer is positioned on the front surface of the substrate, an opening is arranged at a preset position of the dielectric layer, and the opening exposes the piezoresistor;
The second groove is positioned on the front surface of the substrate and is positioned in the high-range area;
A third groove positioned below the second groove and communicated with the second groove;
The fourth groove is positioned at the side edge of the third groove and is communicated with the third groove;
the metal layer is positioned above the dielectric layer, and is filled in the opening and is electrically connected with the piezoresistor;
a fifth trench located in the first trench;
And the sixth groove is positioned on the front surface of the substrate, corresponds to the fifth groove in the vertical direction and is communicated with the fifth groove.
9. The dual range acceleration sensor structure of claim 8, wherein: the substrate comprises a (111) monocrystalline silicon wafer, the second trenches are arranged along <110> and <211> crystal directions, and the fifth trenches are arranged along <110> and <211> crystal directions.
10. The dual range acceleration sensor structure of claim 8, wherein: the substrate bonding device further comprises a support base, wherein the support base is positioned on the back surface of the substrate and bonded with the substrate.
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| CN202310563736.9A CN119001144A (en) | 2023-05-18 | 2023-05-18 | Double-range acceleration sensor structure and manufacturing method |
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| CN202310563736.9A CN119001144A (en) | 2023-05-18 | 2023-05-18 | Double-range acceleration sensor structure and manufacturing method |
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