CN117705193A

CN117705193A - MEMS pressure sensor chip with temperature measuring function and manufacturing method thereof

Info

Publication number: CN117705193A
Application number: CN202311810738.XA
Authority: CN
Inventors: 王竞轩; 陈敏; 马清杰
Original assignee: Suzhou Yuexin Micro Sensing Technology Co ltd
Current assignee: Suzhou Yuexin Micro Sensing Technology Co ltd
Priority date: 2023-12-26
Filing date: 2023-12-26
Publication date: 2024-03-15

Abstract

The invention provides a MEMS pressure sensor chip with a temperature measuring function and a manufacturing method thereof, wherein the MEMS pressure sensor chip comprises: the device comprises a supporting layer, a device layer positioned on the front side of the supporting layer, a groove penetrating through the device layer from the back side of the device layer to divide the device layer into a pressure sensitive area and a temperature measuring area, an insulating part filled in the groove, a piezoresistive structure formed in the pressure sensitive area, a temperature measuring structure formed in the temperature measuring area and a first cavity arranged in the supporting layer and opposite to the pressure sensitive area. Compared with the prior art, the temperature measuring area and the device layer of the pressure sensitive area can simultaneously keep different electric potentials and are not interfered with each other due to the grooves and the insulating parts filled in the grooves, so that the problem of inaccurate temperature acquisition of the MEMS pressure sensor chip in the prior art is solved.

Description

MEMS pressure sensor chip with temperature measuring function and manufacturing method thereof

[ field of technology ]

The invention relates to the technical fields of sensor technology and micro-electromechanical systems, in particular to a MEMS pressure sensor chip with a chip temperature measuring function and a manufacturing method thereof.

[ background Art ]

Along with the development demand of social intelligence, the application field of the pressure sensor is wider and wider, and the precision requirement is higher and higher; MEMS (Micro Electro Mechanical Systems ) piezoresistive pressure sensors are favored in the market for their low cost, high sensitivity, and high resolution. The accuracy of the MEMS piezoresistive pressure sensor is greatly affected by temperature, and the conditioning chip is required to collect temperature data of the MEMS pressure sensor chip in real time and perform real-time temperature compensation.

In the prior art, the substrate of the MEMS pressure Sensor chip and the cathode of the temperature measuring diode are of the same polarity, and can only work alternately (the substrate is of a high level when the pressure sensitive component works, and the substrate is of a low level when the temperature measuring diode works), for example, a High Stability Line STARe series pressure Sensor of the Frist Sensor. Because the pressure-sensitive component and the temperature-measuring diode on the existing MEMS pressure sensor chip can not work simultaneously, the temperature acquisition of the MEMS pressure sensor chip is inaccurate.

Therefore, there is a need to propose a solution to overcome the above-mentioned problems.

[ invention ]

The invention aims to provide an MEMS pressure sensor chip with a chip temperature measuring function and a manufacturing method thereof, which can solve the problem of inaccurate temperature acquisition of the MEMS pressure sensor chip in the prior art.

According to one aspect of the present invention, there is provided a MEMS pressure sensor chip with a temperature measurement function, comprising: a support layer having a front side and a back side; a device layer having a front side and a back side, the device layer being located on the front side of the support layer, and the front side of the device layer being adjacent to the front side of the support layer; the groove penetrates through the device layer from the back surface of the device layer, and the groove separates the device layer into a pressure sensitive area and a temperature measuring area; an insulating member filled in the trench; the temperature measuring structure is formed in the temperature measuring area; a piezoresistive structure formed in the pressure sensitive region; and the first cavity is arranged in the supporting layer and is opposite to the pressure sensitive area.

According to another aspect of the present invention, the present invention provides a method for manufacturing a MEMS pressure sensor chip with a temperature measurement function, including: providing a first substrate with a front surface and a back surface, and etching into the first substrate from the front surface of the first substrate to form a first cavity; providing a second substrate having a front side and a back side; bonding the front surface of the first substrate etched with the first cavity with the front surface of the second substrate, so that the first substrate and the second substrate are combined into a whole; thinning the second substrate from the back side of the second substrate; selectively etching the back surface of the thinned second substrate to form a groove penetrating through the second substrate, wherein the groove divides the thinned second substrate into a pressure sensitive area and a temperature measuring area, and the pressure sensitive area is opposite to the first cavity; performing insulation treatment on the back surface of the thinned second substrate to form an insulation part filled in the groove; and forming a piezoresistance structure in the pressure sensitive area and forming a temperature measuring structure in the temperature measuring area.

Compared with the prior art, the invention enables the pressure-sensitive component (or the pressure-sensitive structure) and the temperature-measuring diode (or the temperature-measuring triode) on the same MEMS pressure sensor chip to be separated on the substrate, and realizes that the pressure-sensitive component and the temperature-measuring diode (or the temperature-measuring triode) work simultaneously without interference, thereby solving the problem of inaccurate temperature acquisition of the MEMS pressure sensor chip in the prior art.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is a schematic flow chart of a method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to a first embodiment of the present invention;

FIGS. 2-13 are longitudinal cross-sectional views of structures corresponding to the steps shown in FIG. 1 in one embodiment of the present invention;

FIG. 14 is a longitudinal cross-sectional view of a MEMS pressure sensor chip with temperature measurement function in a first embodiment of the present invention;

FIG. 15 is a longitudinal cross-sectional view of a MEMS pressure sensor chip with temperature measurement in a second embodiment of the present invention;

FIG. 16 is a longitudinal cross-sectional view of a MEMS pressure sensor chip with temperature measurement in a third embodiment of the present invention;

FIG. 17 is a schematic flow chart of a method for fabricating a MEMS pressure sensor chip with temperature measurement in a second embodiment of the invention;

FIGS. 18-29 are longitudinal cross-sectional views of structures corresponding to the steps shown in FIG. 17 in one embodiment of the present invention;

FIG. 30 is a longitudinal cross-sectional view of a MEMS pressure sensor chip with temperature measurement in a fourth embodiment of the present invention;

fig. 31 is a longitudinal sectional view of a MEMS pressure sensor chip with temperature measurement function in a fifth embodiment of the present invention.

[ detailed description ] of the invention

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless specifically stated otherwise, the terms connected, or connected herein denote an electrical connection, either directly or indirectly.

Fig. 1 is a schematic flow chart of a method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to a first embodiment of the present invention; referring to fig. 2-13, there are shown longitudinal sectional views of a structure according to the present invention corresponding to the steps shown in fig. 1 in one embodiment. The manufacturing method of the MEMS pressure sensor chip with the temperature measuring function shown in FIG. 1 comprises the following steps.

In step A1, as shown in fig. 2, a first substrate 210 having a front surface and a back surface is provided, and a first cavity 212 is etched into the first substrate 210 from the front surface of the first substrate 210. The depth of the first cavity 212 may be 2-10 um.

In step A2, as shown in fig. 3, a second substrate 220 having a front surface and a back surface is provided, and oxidation treatment is performed on the front surface of the second substrate 220 to form a first insulating layer 230.

In step A3, as shown in fig. 4, the front surface of the first substrate 210 etched with the first cavity 212 and the first insulating layer 230 are bonded such that the first substrate 210 and the second substrate 220 are integrated. In a specific embodiment, the bonding of the front surface of the first substrate 210 and the first insulating layer 230 is vacuum bonding, and the first cavity 212 is a vacuum cavity.

Step A4, as shown in fig. 5, the second substrate 220 after polishing bonding is thinned from the back surface of the second substrate 220. Wherein the thickness of the thinned second substrate 220 is smaller than the thickness of the first substrate 210.

Step A5, as shown in fig. 6, etching is selectively performed from the back surface of the thinned second substrate 220 to form a trench 240 penetrating the second substrate 220 and terminating (or stopping) at the first insulating layer 230, where the trench 240 separates the thinned second substrate 220 into a pressure sensitive region 222 and a temperature measuring region 224. Wherein the pressure sensitive area 222 is opposite the first cavity 212.

Step A6, performing an insulation process on the thinned back surface of the second substrate 220 to form an insulation member 252 filled in the trench 240.

The step A6 specifically includes:

step a61, as shown in fig. 7, forming a third insulating layer 250 on the back surface of the thinned second substrate 220 and in the trench 240;

in step a62, as shown in fig. 8, the thinned third insulating layer 250 on the back surface of the second substrate 220 is etched away, and the third insulating layer 250 filled in the trench 240 remains, and the third insulating layer 250 filled in the trench 240 may be referred to as an insulating member 252. In a specific embodiment, the third insulating layer 250 and the insulating member 252 may be silicon oxide or silicon nitride or other insulating material.

In step A7, a piezoresistive structure (not shown) is formed in the pressure sensitive region 222 of the second substrate 220, and a temperature measuring diode (not shown) is formed in the temperature measuring region 224 of the second substrate 220.

The step A7 specifically includes:

step a71, as shown in fig. 9, patterning (or selectively performing) N-type heavy doping and P-type doping (the doping sequence is not fixed but is within the protection range) respectively on the back surface of the thinned second substrate 220 filled with the insulating member 252, so as to form a first n+ active region 261 and a p+ layer 266 which are spaced apart from each other in the pressure sensitive region 222; to form a second n+ active region 262 and a first p+ active region 265 spaced apart from each other in the temperature measuring region 224, thereby forming a temperature measuring diode in the temperature measuring region 224;

Step a72, as shown in fig. 10, etching the side surface of the pressure sensitive region 222 away from the first substrate 210 selectively to etch the p+ layer 266 into a p+ protrusion structure 263, wherein the p+ protrusion structure 263 protrudes from the side surface of the pressure sensitive region 222 away from the first substrate 210, so as to form a bridge piezoresistive structure in the pressure sensitive region 222; meanwhile, a side surface of the temperature measurement region 224 away from the first substrate 210 is selectively etched, so that the second n+ active region 262 and the first p+ active region 265 protrude from the side surface of the temperature measurement region 224 away from the first substrate 210. In another embodiment, the periphery of the first n+ active region 261 in the side surface of the pressure sensitive region 222 away from the first substrate 210 may not be etched, i.e., the first n+ active region 261 need not protrude from the side surface of the pressure sensitive region 222 away from the first substrate 210; the side surface of the temperature measurement region 224 away from the first substrate 210 may not be etched, i.e., the second n+ active region 262 and the first p+ active region 265 do not need to protrude from the side surface of the temperature measurement region 224 away from the first substrate 210. That is, the temperature measuring diode formed in the temperature measuring region 224 may have a convex structure or a planar structure (see fig. 16 for details). In other words, in step a72, at least a surface of the pressure sensitive region 222 on a side away from the first substrate 210 is selectively etched, and the p+ layer 266 is etched to form a p+ protrusion structure 263, so as to form a piezoresistive structure in the pressure sensitive region 222.

In step A8, as shown in fig. 11, a second insulating layer 270 is formed on the back surface of the thinned second substrate 220 with the temperature sensing diode and piezoresistive structure formed thereon, and a conductive window 272 penetrating the second insulating layer 270 is selectively etched in the second insulating layer 270. Specifically, on the second insulating layer 270, corresponding conductive windows 272 penetrating the second insulating layer 270 are disposed at corresponding positions of the first n+ active region 261, the second n+ active region 262, the p+ protrusion structure 263 and the first p+ active region 265, respectively.

In step A9, as shown in fig. 12, a metal interconnection layer 280 is grown and etched on the second insulating layer 270 formed with the conductive window 272, thereby forming a circuit structure. The metal interconnection layer 280 includes a first power electrode 282, a first ground electrode 284, a second power electrode 286, a second ground electrode 288, a bridge output electrode (not shown), and a metal interconnection line (not shown) spaced apart from each other, wherein the first power electrode 282 is electrically connected to one ends of the first n+ active region 261 and the p+ protrusion structure 263 through the corresponding conductive window 272; the first ground electrode 284 is electrically connected to the other end of the p+ protrusion structure 263 through the corresponding conductive window 272; the second power electrode 286 is electrically connected to the first p+ active region 265 through the corresponding conductive window 272; the second ground electrode 288 is electrically connected to the second n+ active region 262 via the corresponding conductive window 272.

It is noted that, until step A9, the pressure sensor chip is of a pressure-insulating type; if step a10 is added in the fabrication of the differential pressure type, as shown in fig. 13, after the metal interconnection layer 280 is formed, deep silicon etching is performed from the back surface of the first substrate 210 into the first substrate 210 to form a second cavity 214, where the second cavity 214 connects the first cavity 212 with the outside. The projection area of the second cavity 214 on the front surface of the first substrate 210 is located in the projection area of the first cavity 212 on the front surface of the first substrate 210, that is, the projection area of the second cavity 214 on the front surface of the first substrate 210 is less than or equal to the projection area of the first cavity 212 on the front surface of the first substrate 210.

It should be noted that, the first insulating layer 230 is not an essential structure for the MEMS pressure sensor chip, so step A3 may also be to bond the front surface of the first substrate 210 etched with the first cavity 212 and the front surface of the second substrate 220, so that the first substrate 210 and the second substrate 220 are combined into a whole. The first N + active region 261 is not a piezoresistive structure, which is functionally unnecessary, but is configured to make the raised piezoresistive structure more stable.

It should be specifically noted that in the embodiments shown in fig. 2-13, the first substrate 210 may be referred to as a support layer; the thinned second substrate 220 may be referred to as a device layer; the first substrate 210 is an N-type single crystal silicon wafer; the second substrate 220 is an N-type monocrystalline silicon wafer; the doping concentration of the first n+ active region 261 and the second n+ active region 262 is higher than the doping concentration of the first substrate 210 and the second substrate 220.

According to another aspect of the invention, the invention provides a MEMS pressure sensor chip with a temperature measurement function. Fig. 14 is a longitudinal sectional view of a MEMS pressure sensor chip with temperature measurement function according to a first embodiment of the present invention. The MEMS pressure sensor chip with temperature measurement function shown in fig. 14 is manufactured by steps A1-A9 in the manufacturing method of the MEMS pressure sensor chip with temperature measurement function shown in fig. 1.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 14 includes a support layer 210, a device layer 220, a first insulating layer 230, a trench 240, an insulating member 252, a first cavity 212, a temperature measuring diode (not identified), and a piezoresistive structure (not identified).

Wherein the support layer 210 has a front side and a back side; the device layer 220 has a front side and a back side; the first insulating layer 230 is sandwiched between the front side of the support layer 210 and the front side of the device layer 220; a trench 240 extends through the device layer 210 from the back side of the device layer 220 to the first insulating layer 230, the trench 240 separating the device layer 220 into a pressure sensitive region 222 and a temperature measurement region 224; the insulating member 252 fills in the trench 240; a temperature measuring diode (not identified) is formed in the temperature measuring region 224; a piezoresistive structure (not identified) is formed in the pressure sensitive region 222; the first cavity 212 is disposed in the support layer 210 and opposite the pressure sensitive region 222.

In the embodiment shown in FIG. 14, the piezoresistive structure (not identified) includes first N+ active region 261 and P+ raised structure 263 selectively formed into pressure sensitive region 222 from a side surface of pressure sensitive region 222 remote from first substrate 210, with first N+ active region 261 and P+ raised structure 263 being spaced apart from each other. A temperature sensing diode (not shown) includes a second n+ active region 262 and a first p+ active region 265 selectively formed into the temperature sensing region 224 from a side surface of the temperature sensing region 224 remote from the first substrate 210, and the second n+ active region 262 and the first p+ active region 265 are spaced apart from each other.

In the embodiment shown in fig. 14, support layer 210 is an N-type monocrystalline silicon wafer and device layer 220 is an N-type monocrystalline silicon wafer; the doping concentration of the first n+ active region 261 and the second n+ active region 262 is higher than the doping concentration of the support layer 210 and the device layer 220; the thickness of the device layer 220 is less than the thickness of the support layer 210.

In the embodiment shown in fig. 14, the first n+ active region 261 and the p+ protrusion structure 263 protrude from a surface of the pressure sensitive region 222 on a side away from the first substrate 210; the second n+ active region 262 and the first p+ active region 265 protrude from a surface of the temperature measuring region 224 away from the first substrate 210.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 14 further includes a second insulating layer 270, the second insulating layer 270 covering the back surface of the device layer 220 formed with the temperature sensing diode and piezoresistive structure; the second insulating layer 270 is selectively etched with a conductive window 272 extending through the second insulating layer 270. Specifically, on the second insulating layer 270, corresponding conductive windows 272 penetrating through the second insulating layer 270 are respectively disposed at corresponding positions of the first n+ active region 261, the second n+ active region 262, the p+ protruding structures 263 and the first p+ active region 265.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 14 further includes a metal interconnection layer 280, and the metal interconnection layer 280 is formed on the second insulating layer 270 provided with the conductive window 272. The metal interconnection layer 280 includes a first power electrode 282, a first ground electrode 284, a second power electrode 286, a second ground electrode 288, a bridge output electrode (not shown), and a metal interconnection line (not shown) spaced apart from each other, wherein the first power electrode 282 is electrically connected to one ends of the first n+ active region 261 and the p+ protrusion structure 263 through the corresponding conductive window 272; the first ground electrode 284 is electrically connected to the other end of the p+ protrusion structure 263 through the corresponding conductive window 272; the second power electrode 286 is electrically connected to the first p+ active region 265 through the corresponding conductive window 272; the second ground electrode 288 is electrically connected to the second n+ active region 262 via the corresponding conductive window 272.

It should be noted that the MEMS pressure sensor chip with temperature measurement function shown in fig. 14 is of a pressure-insulation type, the first cavity 212 extends from the front surface of the supporting layer 210 into the supporting layer 210, and the first cavity 212 is a vacuum cavity. Fig. 15 is a longitudinal sectional view of a MEMS pressure sensor chip with temperature measurement function according to a second embodiment of the present invention, which is of differential pressure type. Compared with fig. 14, the MEMS pressure sensor chip with temperature measurement function shown in fig. 15 further includes a second cavity 214, where the second cavity 214 extends from the back surface of the support layer 210 into the support layer 210, and the second cavity 214 communicates the first cavity 212 with the outside; the projection area of the second cavity 214 on the front surface of the support layer 210 is located within the projection area of the first cavity 212 on the front surface of the support layer 210, that is, the projection area of the second cavity 214 on the front surface of the first substrate 210 is less than or equal to the projection area of the first cavity 212 on the front surface of the first substrate 210.

Referring to fig. 16, which is a longitudinal section view of a MEMS pressure sensor chip with temperature measurement function according to a third embodiment of the present invention, compared with fig. 14, in the MEMS pressure sensor chip with temperature measurement function shown in fig. 16, only the p+ protrusion 263 protrudes from the surface of the pressure sensitive area 222 away from the first substrate 210; the first n+ active region 261 does not protrude from a surface of the pressure sensitive region 222 on a side remote from the first substrate 210; the second n+ active region 262 and the first p+ active region 265 do not protrude from a surface of the temperature measuring region 224 away from the first substrate 210. That is, the temperature measuring diode formed in the temperature measuring region 224 may have a convex structure or a planar structure; at least the p+ protrusion structure 263 protrudes from a surface of the pressure-sensitive region 222 away from the first substrate 210.

It should be noted that, for the MEMS pressure sensor chip with temperature measurement function shown in fig. 14 to 16, the first insulating layer 230 is not an essential structure for the MEMS pressure sensor chip, so it can be said that the device layer 220 is located on the front surface of the support layer 210, and the front surface of the device layer 220 is adjacent to the front surface of the support layer 210. The first N + active region 261 is not a piezoresistive structure, which is functionally unnecessary, but is configured to make the raised piezoresistive structure more stable.

The operation principle of the MEMS pressure sensor chip with temperature measurement function shown in fig. 14 to 16 is specifically described below.

In the pressure sensitive region 222, when the piezoresistive structure works, a high level is applied to the first power electrode 282 of the metal interconnection layer 280, and one ends of the first n+ active region 261 and the p+ protrusion structure 263 which are electrically contacted with the high level are electrically interconnected with the N-type device layer 220; the first ground electrode 284 of the metal interconnect layer 280 is low and the other end of the p+ protrusion 263 in electrical contact with it is reverse biased off the PN junction formed by the N-type device layer 220, so that the N-type device layer 220 of the voltage sensitive region 222 is high at this time.

When the temperature measuring region 224 and the temperature measuring diode work, a high level is arranged on the second power electrode 286 of the metal interconnection layer 280, and a PN junction formed by the first P+ active region 265 and the N-type device layer 220 which are electrically contacted with the high level is biased in the forward direction; the second ground electrode 288 of the metal interconnect layer 280 is low and the second n+ active region 262 in electrical contact therewith is electrically interconnected with the N-type device layer 220; therefore, the N-type device layer 220 of the temperature measurement region 224 is at a low level.

Due to the presence of the trench 240 and the insulating member 252 filled in the trench 240, the device layer 220 of the temperature measurement region 224 and the pressure sensitive region 222 can be kept at a low level and a high level at the same time, without interfering with each other.

Fig. 17 is a schematic flow chart of a method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to a second embodiment of the present invention; referring to fig. 18-29, there is shown a longitudinal section of a structure according to the present invention corresponding to the steps shown in fig. 17 in one embodiment. The manufacturing method of the MEMS pressure sensor chip with the temperature measuring function shown in FIG. 17 comprises the following steps.

In step B1, as shown in fig. 18, a first substrate 210 having a front surface and a back surface is provided, and a first cavity 212 is etched into the first substrate 210 from the front surface of the first substrate 210. The depth of the first cavity 212 may be 2-10 um.

In step B2, as shown in fig. 19, a second substrate 220 having a front surface and a back surface is provided, and oxidation treatment is performed on the front surface of the second substrate 220 to form a first insulating layer 230.

In step B3, as shown in fig. 20, the front surface of the first substrate 210 etched with the first cavity 212 and the first insulating layer 230 are bonded such that the first substrate 210 and the second substrate 220 are integrated. In a specific embodiment, the bonding of the front surface of the first substrate 210 and the first insulating layer 230 is vacuum bonding, and the first cavity 212 is a vacuum cavity.

Step B4, as shown in fig. 21, the bonded second substrate 220 is thinned from the back surface of the second substrate 220. Wherein the thickness of the thinned second substrate 220 is smaller than the thickness of the first substrate 210.

Step B5, as shown in fig. 22, etching is selectively performed from the back surface of the thinned second substrate 220 to form a trench 240 penetrating the second substrate 220 and terminating (or stopping) at the first insulating layer 230, wherein the trench 240 separates the thinned second substrate 220 into a pressure sensitive region 222 and a temperature measuring region 224. Wherein the pressure sensitive area 222 is opposite the first cavity 212.

Step B6, performing an insulation process on the thinned back surface of the second substrate 220 to form an insulation member 252 filled in the trench 240.

Wherein, step B6 specifically includes:

step B61, as shown in fig. 23, forming a third insulating layer 250 on the back surface of the thinned second substrate 220 and in the trench 240;

in step B62, as shown in fig. 24, the thinned third insulating layer 250 on the back surface of the second substrate 220 is etched away, so as to leave the third insulating layer 250 filled in the trench 240, and the third insulating layer 250 filled in the trench 240 may be referred to as an insulating member 252. In a specific embodiment, the third insulating layer 250 and the insulating member 252 may be silicon oxide or silicon nitride or other insulating material.

In step B7, a piezoresistive structure (not shown) is formed in the pressure sensitive region 222 of the second substrate 220, and a temperature measuring transistor (not shown) is formed in the temperature measuring region 224 of the second substrate 220.

Wherein, step B7 specifically includes:

step B71, as shown in fig. 25, patterning (or selectively performing) N-type heavy doping, P-type light doping and P-type heavy doping respectively (the doping sequence is not fixed but is within the protection range) is performed on the back surface of the thinned second substrate 220 filled with the insulating member 252, so as to form a first n+ active region 261 and a p+ layer 266 which are spaced apart from each other in the pressure sensitive region 222; forming a P-well 267, a second n+ active region 262, a third n+ active region 268 and a first p+ active region 265 in the temperature measurement region 224, wherein the P-well 267 and the third n+ active region 268 are spaced apart from each other, and the first p+ active region 265 and the second n+ active region 262 are spaced apart from each other and arranged in the P-well 267, so that a temperature transistor is formed in the temperature measurement region 224; wherein the first n+ active region 261, the second n+ active region 262 and the third n+ active region 268 are heavily doped N-type; the P-well 267 is lightly doped P-type, and the first p+ active region 265 is heavily doped P-type, i.e. the P-type doping concentration of the P-well 267 is smaller than the doping concentration of the first p+ active region 265; the junction depth (or depth) of the P-well 267 is greater than the junction depth of the first p+ active region 265, and the junction depth (or depth) of the P-well 267 is greater than the junction depths of the second n+ active region 262 and the third n+ active region 268.

In step B72, as shown in fig. 26, a side surface of the pressure sensitive region 222 away from the first substrate 210 is selectively etched to etch the p+ layer 266 into a p+ protrusion structure 263, where the p+ protrusion structure 263 protrudes from the side surface of the pressure sensitive region 222 away from the first substrate 210, so as to form a bridge piezoresistive structure in the pressure sensitive region 222. It should be noted that the p+ protrusion structure 263 may be lightly doped P-type or heavily doped P-type.

In step B8, as shown in fig. 27, a second insulating layer 270 is formed on the back surface of the thinned second substrate 220 with the temperature sensing transistor and piezoresistive structure formed thereon, and a conductive window 272 penetrating the second insulating layer 270 is selectively etched in the second insulating layer 270. Specifically, on the second insulating layer 270, corresponding conductive windows 272 penetrating the second insulating layer 270 are respectively disposed at corresponding positions of the first n+ active region 261, the second n+ active region 262, the third n+ active region 268, the p+ protruding structure 263 and the first p+ active region 265.

In step B9, as shown in fig. 28, a metal interconnection layer 280 is grown and etched on the second insulating layer 270 formed with the conductive window 272, thereby forming a circuit structure. The metal interconnection layer 280 includes a first power electrode 282, a first ground electrode 284, a second power electrode 286, a second ground electrode 288, a bridge output electrode (not shown), and a metal interconnection line (not shown) spaced apart from each other, wherein the first power electrode 282 is electrically connected to one ends of the first n+ active region 261 and the p+ protrusion structure 263 through the corresponding conductive window 272; the first ground electrode 284 is electrically connected to the other end of the p+ protrusion structure 263 through the corresponding conductive window 272; the second power electrode 286 is electrically connected to the first p+ active region 265 and the third n+ active region 268 through the corresponding conductive window 272; the second ground electrode 288 is electrically connected to the second n+ active region 262 via the corresponding conductive window 272.

It is noted that, until step B9, the pressure sensor chip is of a pressure-insulating type; if step B10 is added in the fabrication of the differential pressure type, as shown in fig. 29, after the metal interconnection layer 280 is formed, deep silicon etching is performed from the back surface of the first substrate 210 into the first substrate 210 to form a second cavity 214, and the second cavity 214 connects the first cavity 212 with the outside. The projection area of the second cavity 214 on the front surface of the first substrate 210 is located in the projection area of the first cavity 212 on the front surface of the first substrate 210, that is, the projection area of the second cavity 214 on the front surface of the first substrate 210 is less than or equal to the projection area of the first cavity 212 on the front surface of the first substrate 210.

It should be noted that, the first insulating layer 230 is not an essential structure for the MEMS pressure sensor chip, so step B3 may also be to bond the front surface of the first substrate 210 etched with the first cavity 212 and the front surface of the second substrate 220, so that the first substrate 210 and the second substrate 220 are combined into a whole. The first N + active region 261 is not a piezoresistive structure, which is functionally unnecessary, but is configured to make the raised piezoresistive structure more stable.

It should be noted that, in the embodiment shown in fig. 18 to 29, the first substrate 210 may be referred to as a support layer; the thinned second substrate 220 may be referred to as a device layer; the first substrate 210 is an N-type single crystal silicon wafer; the second substrate 220 is an N-type monocrystalline silicon wafer; the doping concentrations of the first n+ active region 261, the second n+ active region 262, and the third n+ active region 268 are higher than the doping concentrations of the first substrate 210 and the second substrate 220.

According to another aspect of the invention, the invention provides a MEMS pressure sensor chip with a temperature measurement function. Fig. 30 is a longitudinal sectional view of a MEMS pressure sensor chip with temperature measurement function according to a fourth embodiment of the present invention. The MEMS pressure sensor chip with temperature measurement function shown in fig. 30 is manufactured by steps B1 to B9 in the manufacturing method of the MEMS pressure sensor chip with temperature measurement function shown in fig. 17.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 30 includes a support layer 210, a device layer 220, a first insulating layer 230, a trench 240, an insulating member 252, a first cavity 212, a temperature measuring triode (not identified), and a piezoresistive structure (not identified).

Wherein the support layer 210 has a front side and a back side; the device layer 220 has a front side and a back side; the first insulating layer 230 is sandwiched between the front side of the support layer 210 and the front side of the device layer 220; a trench 240 extends through the device layer 210 from the back side of the device layer 220 to the first insulating layer 230, the trench 240 separating the device layer 220 into a pressure sensitive region 222 and a temperature measurement region 224; the insulating member 252 fills in the trench 240; a temperature measuring transistor (not identified) is formed in the temperature measuring region 224; a piezoresistive structure (not identified) is formed in the pressure sensitive region 222; the first cavity 212 is disposed in the support layer 210 and opposite the pressure sensitive region 222.

In the embodiment shown in FIG. 30, the piezoresistive structure (not identified) includes first N+ active region 261 and P+ raised structure 263 selectively formed into pressure sensitive region 222 from a side surface of pressure sensitive region 222 remote from first substrate 210, with first N+ active region 261 and P+ raised structure 263 being spaced apart from each other. The temperature transistor (not shown) includes a P-well region 267, a second n+ active region 262, a third n+ active region 268 and a first p+ active region 265 selectively formed in the temperature measurement region 224 from a side surface of the temperature measurement region 224 away from the first substrate 210, wherein the P-well region 267 and the third n+ active region 268 are spaced apart from each other, and the first p+ active region 265 and the second n+ active region 262 are spaced apart from each other and disposed in the P-well region 267. Wherein the first n+ active region 261, the second n+ active region 262 and the third n+ active region 268 are heavily doped N-type; the P-well 267 is lightly doped P-type, and the first p+ active region 265 is heavily doped P-type, i.e. the P-type doping concentration of the P-well 267 is smaller than the doping concentration of the first p+ active region 265; the junction depth (or depth) of the P-well 267 is greater than the junction depth of the first p+ active region 265, and the junction depth (or depth) of the P-well 267 is greater than the junction depths of the second n+ active region 262 and the third n+ active region 268. It should be noted that the p+ protrusion structure 263 may be lightly doped P-type or heavily doped P-type.

In the embodiment shown in fig. 30, support layer 210 is an N-type monocrystalline silicon wafer and device layer 220 is an N-type monocrystalline silicon wafer; the doping concentration of the first n+ active region 261, the second n+ active region 262, and the third n+ active region 268 is higher than the doping concentration of the support layer 210 and the device layer 220; the thickness of the device layer 220 is less than the thickness of the support layer 210; the p+ protrusion structure 263 protrudes from a surface of the pressure sensitive region 222 away from the first substrate 210.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 30 further includes a second insulating layer 270, where the second insulating layer 270 covers the back surface of the device layer 220 where the temperature measuring transistor and the piezoresistive structure are formed; the second insulating layer 270 is selectively etched with a conductive window 272 extending through the second insulating layer 270. Specifically, on the second insulating layer 270, corresponding conductive windows 272 penetrating through the second insulating layer 270 are respectively disposed at corresponding positions of the first n+ active region 261, the second n+ active region 262, the third n+ active region 268, the p+ protruding structure 263 and the first p+ active region 265.

The MEMS pressure sensor chip with temperature measurement function shown in fig. 30 further includes a metal interconnection layer 280, and the metal interconnection layer 280 is formed on the second insulating layer 270 provided with the conductive window 272. The metal interconnection layer 280 includes a first power electrode 282, a first ground electrode 284, a second power electrode 286, a second ground electrode 288, a bridge output electrode (not shown), and a metal interconnection line (not shown) spaced apart from each other, wherein the first power electrode 282 is electrically connected to one ends of the first n+ active region 261 and the p+ protrusion structure 263 through the corresponding conductive window 272; the first ground electrode 284 is electrically connected to the other end of the p+ protrusion structure 263 through the corresponding conductive window 272; the second power electrode 286 is electrically connected to the first p+ active region 265 and the third n+ active region 268 through the corresponding conductive window 272; the second ground electrode 288 is electrically connected to the second n+ active region 262 via the corresponding conductive window 272.

It should be noted that the MEMS pressure sensor chip with temperature measurement function shown in fig. 30 is of a pressure-insulation type, the first cavity 212 extends from the front surface of the supporting layer 210 into the supporting layer 210, and the first cavity 212 is a vacuum cavity. Fig. 31 is a longitudinal sectional view of a MEMS pressure sensor chip with temperature measurement function according to a fifth embodiment of the present invention, which is of differential pressure type. Compared with fig. 30, the MEMS pressure sensor chip with temperature measurement function shown in fig. 31 further includes a second cavity 214, the second cavity 214 extends from the back surface of the support layer 210 into the support layer 210, and the second cavity 214 communicates the first cavity 212 with the outside; the projection area of the second cavity 214 on the front surface of the support layer 210 is located within the projection area of the first cavity 212 on the front surface of the support layer 210, that is, the projection area of the second cavity 214 on the front surface of the first substrate 210 is less than or equal to the projection area of the first cavity 212 on the front surface of the first substrate 210.

It should be noted that, for the MEMS pressure sensor chip with temperature measurement function shown in fig. 30 and 31, the first insulating layer 230 is not an essential structure for the MEMS pressure sensor chip, so it can be said that the device layer 220 is located on the front surface of the support layer 210, and the front surface of the device layer 220 is adjacent to the front surface of the support layer 210. The first N + active region 261 is not a piezoresistive structure, which is functionally unnecessary, but is configured to make the raised piezoresistive structure more stable.

The operation principle of the MEMS pressure sensor chip with temperature measurement function shown in fig. 30 and 31 will be specifically described below.

When the temperature measuring region 224 and the temperature measuring triode work, a high level is arranged on the second power electrode 286 of the metal interconnection layer 280, and the first P+ active region 265 (base) and the third N+ active region 268 (collector) which are electrically contacted with the high level are in short circuit; the second ground electrode 288 of the metal interconnection layer 280 is electrically connected to the second n+ active region 262 (emitter), and at this time, the N-type device layer 220 of the temperature measurement region 224 is at a high level, but the N-type device layer 220 of the temperature measurement region 224 and the N-type device layer 220 of the voltage sensitive region 222 are at a high level but have different potentials, so that they do not interfere with each other. Due to the presence of the trench 240 and the insulating member 252 filled in the trench 240, the device layer 220 of the temperature measurement region 224 and the pressure sensitive region 222 can be simultaneously maintained at different potentials without interfering with each other.

In summary, the MEMS pressure sensor chip with the chip temperature measuring function and the manufacturing method thereof provided by the invention have the following advantages:

1. the pressure sensitive structure and the temperature measuring structure (such as a temperature measuring diode or a temperature measuring triode) on the MEMS pressure sensor chip can work simultaneously without interference;

2. the temperature measuring structure (such as a temperature measuring diode or a temperature measuring triode) and the pressure sensitive structure have good process compatibility, a photomask is not additionally added, and the manufacturing is simple and the method is suitable for mass production;

3. the isolation structure of the pressure sensitive structure and the temperature measuring structure (such as a temperature measuring diode or a temperature measuring triode) is simple and has high reliability.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

The above description is merely of preferred embodiments of the present invention, and the scope of the present invention is not limited to the above embodiments, but all equivalent modifications or variations according to the present disclosure will be within the scope of the claims.

Claims

1. The MEMS pressure sensor chip with the temperature measuring function is characterized by comprising:

a support layer having a front side and a back side;

a device layer having a front side and a back side, the device layer being located on the front side of the support layer, and the front side of the device layer being adjacent to the front side of the support layer;

a trench penetrating the device layer from a back surface of the device layer, the trench separating the device layer into a pressure sensitive region and a temperature measurement region;

an insulating member filled in the trench;

the temperature measuring structure is formed in the temperature measuring area;

a piezoresistive structure formed in the pressure sensitive region;

and the first cavity is arranged in the supporting layer and is opposite to the pressure sensitive area.

2. The MEMS pressure sensor chip with temperature measurement function according to claim 1, wherein,

the piezoresistive structure comprises a p+ protrusion structure selectively formed into the pressure sensitive region from a surface of a side of the pressure sensitive region remote from the support layer;

The temperature measuring structure is a temperature measuring diode, the temperature measuring diode comprises a second N+ active region and a first P+ active region which are selectively formed in the temperature measuring region from the surface of one side of the temperature measuring region far away from the supporting layer, and the second N+ active region and the first P+ active region are mutually spaced.

3. The MEMS pressure sensor chip with temperature measurement function as set forth in claim 1, further comprising a second insulating layer and a metal interconnect layer,

the second insulating layer covers the back surface of the device layer on which the temperature measuring diode and the piezoresistance structure are formed, and a conductive window penetrating through the second insulating layer is selectively arranged on the second insulating layer;

the metal interconnection layer comprises a first power electrode, a first grounding electrode, a second power electrode, a second grounding electrode, a bridge output electrode and a metal interconnection line which are mutually spaced;

the first power electrode is electrically connected with one end of the P+ protruding structure through the corresponding conductive window;

the first grounding electrode is electrically connected with the other end of the P+ protruding structure through the corresponding conductive window;

the second power electrode is electrically connected with the first P+ active region through the corresponding conductive window;

The second ground electrode is electrically connected with the second n+ active region through the corresponding conductive window.

4. The MEMS pressure sensor chip with temperature measurement function as claimed in claim 3, further comprising a first insulating layer and a first N+ active region,

the first insulating layer is clamped between the front surface of the supporting layer and the front surface of the device layer;

the first N+ active region is selectively formed in the pressure sensitive region from the surface of the side of the pressure sensitive region away from the first insulating layer, and the first N+ active region and the P+ protrusion structure are spaced from each other;

the first power electrode is electrically connected with the first N+ active region through the corresponding conductive window.

5. The MEMS pressure sensor chip with temperature measurement function as claimed in claim 4, wherein,

the support layer is an N-type support layer, and the device layer is an N-type device layer;

the doping concentration of the first N+ active region and the second N+ active region is higher than that of the supporting layer and the device layer;

the thickness of the device layer is less than the thickness of the support layer.

6. The MEMS pressure sensor chip with temperature measurement function according to claim 1, wherein,

the temperature measuring structure is a temperature measuring triode, the temperature measuring triode comprises a P-well region, a second N+ active region, a third N+ active region and a first P+ active region, the P-well region, the second N+ active region, the third N+ active region and the first P+ active region are formed in the temperature measuring region selectively from the surface of one side, far away from the supporting layer, of the temperature measuring region, the P-well region and the third N+ active region are mutually spaced, and the first P+ active region and the second N+ active region are mutually spaced and arranged in the P-well region.

7. The MEMS pressure sensor chip with temperature measurement function as set forth in claim 6, further comprising a second insulating layer and a metal interconnect layer,

the second insulating layer covers the back surface of the device layer on which the temperature measuring triode and the piezoresistance structure are formed; a conductive window penetrating through the second insulating layer is selectively arranged on the second insulating layer;

the second power electrode is electrically connected with the first P+ active region and the third N+ active region through the corresponding conductive window;

8. The MEMS pressure sensor chip with temperature measurement function as set forth in claim 7, further comprising a first insulating layer and a first n+ active region,

the first N+ active region is selectively formed in the pressure sensitive region from the surface of the side of the pressure sensitive region away from the first insulating layer, and the second N+ active region and the P+ protrusion structure are spaced from each other;

9. The MEMS pressure sensor chip with temperature measurement function according to claim 8, wherein,

The P-well region is lightly doped with P type, and the first P+ active region is heavily doped with P type;

the junction depth of the P-well region is larger than that of the first P+ active region;

the junction depth of the P-well region is larger than that of the second N+ active region;

the junction depth of the P-well region is larger than that of the third N+ active region;

the P+ protruding structure is lightly doped or heavily doped

the doping concentration of the first N+ active region, the second N+ active region and the third N+ active region is higher than that of the supporting layer and the device layer;

10. The MEMS pressure sensor chip with temperature measurement function according to any one of claims 1-9, wherein,

the first cavity extends into the supporting layer from the front surface of the supporting layer, and is a vacuum cavity; or (b)

The MEMS pressure sensor chip further comprises a second cavity, wherein the first cavity extends into the supporting layer from the front surface of the supporting layer; the second cavity extends into the supporting layer from the back surface of the supporting layer, and the second cavity communicates the first cavity with the outside; the projection area of the second cavity on the front surface of the supporting layer is positioned in the projection area of the first cavity on the front surface of the supporting layer.

11. The manufacturing method of the MEMS pressure sensor chip with the temperature measuring function is characterized by comprising the following steps of:

providing a first substrate with a front surface and a back surface, and etching into the first substrate from the front surface of the first substrate to form a first cavity;

providing a second substrate having a front side and a back side;

bonding the front surface of the first substrate etched with the first cavity with the front surface of the second substrate, so that the first substrate and the second substrate are combined into a whole;

thinning the second substrate from the back side of the second substrate;

selectively etching the back surface of the thinned second substrate to form a groove penetrating through the second substrate, wherein the groove divides the thinned second substrate into a pressure sensitive area and a temperature measuring area, and the pressure sensitive area is opposite to the first cavity;

performing insulation treatment on the back surface of the thinned second substrate to form an insulation part filled in the groove;

and forming a piezoresistance structure in the pressure sensitive area and forming a temperature measuring structure in the temperature measuring area.

12. The method for manufacturing the MEMS pressure sensor chip with the temperature measuring function according to claim 11, wherein,

The "performing insulation treatment on the thinned back surface of the second substrate to form an insulation member filled in the trench" includes:

forming a third insulating layer on the back surface of the thinned second substrate and in the groove;

etching the thinned third insulating layer on the back surface of the second substrate, and reserving the third insulating layer in the groove.

13. The method for manufacturing the MEMS pressure sensor chip with the temperature measuring function according to claim 11, wherein,

the temperature measuring structure is a temperature measuring diode,

the step of forming the piezoresistive structure in the pressure sensitive area and forming the temperature measuring structure in the temperature measuring area includes:

patterning N-type heavy doping and P-type doping are respectively carried out on the back surface of the thinned second substrate filled with the insulating component so as to form a P+ layer in the pressure sensitive region, and a second N+ active region and a first P+ active region which are mutually spaced are formed in the temperature measuring region;

and selectively etching the surface of one side of the pressure sensitive area far away from the supporting layer to etch the P+ layer into a P+ protruding structure.

14. The method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to claim 13, further comprising:

Forming a second insulating layer on the back surface of the thinned second substrate provided with the temperature measuring diode and the piezoresistive structure, and selectively etching a conductive window penetrating through the second insulating layer on the second insulating layer;

growing and etching a metal interconnection layer on the second insulating layer with the conductive window;

the metal interconnection layer comprises a first power electrode, a first grounding electrode, a second power electrode, a second grounding electrode, a bridge output electrode and a metal interconnection line which are mutually spaced, wherein the first power electrode is electrically connected with one end of the P+ protruding structure through the corresponding conductive window; the first grounding electrode is electrically connected with the other end of the P+ protruding structure through the corresponding conductive window; the second power electrode is electrically connected with the first P+ active region through the corresponding conductive window; the second ground electrode is electrically connected with the second n+ active region through the corresponding conductive window.

15. The method for fabricating a MEMS pressure sensor chip with temperature measurement according to claim 14, wherein a first insulating layer is formed on a front surface of the second substrate, and the front surface of the first substrate etched with the first cavity is bonded to the first insulating layer, so that the first substrate and the second substrate are integrated;

When the back surface of the thinned second substrate filled with the insulating component is respectively subjected to graphical N-type heavy doping and P-type doping, a first N+ active region is formed in the pressure sensitive region besides the P+ layer;

the first power electrode is electrically connected with the first N+ active region through the corresponding conductive window;

the first substrate is an N-type first substrate, and the second substrate is an N-type second substrate;

the doping concentration of the first N+ active region and the second N+ active region is higher than that of the first substrate and the second substrate;

the thickness of the thinned second substrate is smaller than that of the first substrate.

16. The method for manufacturing the MEMS pressure sensor chip with the temperature measuring function according to claim 11, wherein,

the temperature measuring structure is a temperature measuring triode

patterning the back surface of the thinned second substrate filled with the insulating component to form a p+ layer in the pressure sensitive region, wherein the patterned N-type heavy doping, P-type light doping and P-type heavy doping are respectively carried out on the back surface of the thinned second substrate filled with the insulating component; forming a P-well region, a second N+ active region, a third N+ active region and a first P+ active region in the temperature measuring region, wherein the P-well region and the third N+ active region are mutually spaced, and the first P+ active region and the second N+ active region are mutually spaced and arranged in the P-well region;

And selectively etching the surface of one side of the pressure sensitive area far away from the first insulating layer to etch the P+ layer into a P+ protruding structural surface.

17. The method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to claim 16, further comprising:

forming a second insulating layer on the back surface of the thinned second substrate provided with the temperature measuring triode and the piezoresistance structure, and selectively etching a conductive window penetrating through the second insulating layer on the second insulating layer;

the metal interconnection layer comprises a first power electrode, a first grounding electrode, a second power electrode, a second grounding electrode, a bridge output electrode and a metal interconnection line which are mutually spaced; the first power electrode is electrically connected with one end of the P+ protruding structure through the corresponding conductive window; the first grounding electrode is electrically connected with the other end of the P+ protruding structure through the corresponding conductive window; the second power electrode is electrically connected with the first P+ active region and the third N+ active region through the corresponding conductive window; the second ground electrode is electrically connected with the second n+ active region through the corresponding conductive window.

18. The method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to claim 17, wherein,

a first insulating layer is formed on the front surface of the second substrate, and the front surface of the first substrate etched with the first cavity is bonded with the first insulating layer, so that the first substrate and the second substrate are combined into a whole;

patterning the back surface of the thinned second substrate filled with the insulating component to form a first N+ active region in addition to the P+ layer in the pressure sensitive region when patterning the back surface of the thinned second substrate to form N-type heavy doping, P-type light doping and P-type heavy doping;

19. The method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to claim 18, wherein,

The P+ protruding structure is lightly doped or heavily doped;

the doping concentration of the first N+ active region, the second N+ active region and the third N+ active region is higher than that of the first substrate and the second substrate;

20. The method for manufacturing a MEMS pressure sensor chip with temperature measurement function according to any one of claims 11-19, wherein,

the method further comprises the step of etching from the back surface of the first substrate into the first substrate to form a second cavity, wherein the second cavity is communicated with the first cavity and the outside; the projection area of the second cavity on the front surface of the first substrate is positioned in the projection area of the first cavity on the front surface of the first substrate; or (b)

The first cavity is a vacuum cavity.