Mechanical stress sensing and compensation on a substrate

Abstract

Mechanical stress sensing and compensation on a substrate is disclosed. In described examples, a circuit 500 includes an analog front end 403 arranged to generate an analog stress compensation signal in response to a to-be-compensated analog signal and a first axis stress sense signal (e.g., Vsense_x). The analog front end 403 can include a first precision component (e.g., Rsense_xa) arranged on a piezoelectric material 501 and arranged to generate the to-be-compensated analog signal (e.g., from 510) influenced by a stress applied in the piezoelectric material 501, and a directional stress sensor 440 arranged on the piezoelectric material 501 and coupled to the first precision component. The directional stress sensor 440 is arranged to generate the first axis sense signal in response to a longitudinal force of the stress applied in the piezoelectric material 501. A compensation circuit 520 is arranged to generate a compensation output signal in response to the compensation analog signal and the to-be-compensated analog signal.

Description

Background Technology

[0001] Mechanical stress can affect the physical dimensions and performance of electronic devices, and can also alter the operating parameters of stressed devices. Stress applied to a substrate can change the x-dimensional and / or y-dimensional dimensions of the substrate on which the device is formed, thereby changing the device's operating parameters. Circuit systems used to monitor and help compensate for such mechanical stresses often increase circuit complexity and / or require complex mathematical calculations during post-processing of the measured results. Summary of the Invention

[0002] In the described example, a circuit includes an analog front end arranged to generate an analog stress compensation signal in response to an analog signal to be compensated and a first axial stress sensing signal. The analog front end may include a first precision component (e.g., 220) and an axial stress sensor, the first precision component being disposed on a piezoelectric material and arranged to generate the analog signal to be compensated affected by stress applied in the piezoelectric material, the axial stress sensor being disposed on the piezoelectric material and coupled to the first precision component. The axial stress sensor is arranged to generate the first axial sensing signal in response to the longitudinal resultant force of the stress applied in the piezoelectric material. A compensation circuit is arranged to generate a compensation output signal in response to the compensation analog signal and the analog signal to be compensated. Attached Figure Description

[0003] Figure 1A This is a top view of an example semiconductor wafer.

[0004] Figure 1B yes Figure 1A An orthographic view of an example cross section of an example semiconductor wafer.

[0005] Figure 1C yes Figure 1B An orthographic view of an example cross section of an example semiconductor wafer.

[0006] Figure 2 This is a top view of an example wafer including an example first axial stress sensor.

[0007] Figure 3 This is an example graph showing the response of the example circuit to independently applied X-dimensional normal stress and Y-dimensional normal stress.

[0008] Figure 4 This is a schematic diagram of an analog front-end based on a Wheatstone bridge, used as an example of stress compensation for analog signals.

[0009] Figure 5 This is a schematic diagram of an example of a Wheatstone bridge-based analog front end for feedback-based stress compensation of analog signals.

[0010] Figure 6This is a schematic diagram of an example operational amplifier-controlled current source used for stress compensation of analog signals.

[0011] Figure 7 This is a schematic diagram of an example operational amplifier controlled by an amplifier used for stress compensation of analog signals.

[0012] Figure 8 This is a schematic diagram of an example current-controlled current source used for stress compensation of analog signals.

[0013] Figure 9 It is coupled to Figure 8 A schematic diagram of an example stress-compensated bandgap reference circuit for at least one of the example current-controlled current sources.

[0014] Figure 10 This is a top view of wafer 1000, which is an example wafer including precision devices arranged between mutually orthogonal sensing direction stress sensors.

[0015] Figure 11 This is a top view of wafer 1100, which is an example wafer including precision devices arranged between mutual longitudinal sensing direction stress sensors.

[0016] Figure 12 This is a top view of wafer 1200, which is an example wafer of an example structure including a Wheatstone bridge reference resistor and a stress-sensing resistor.

[0017] Figure 13 An example area of ​​a semiconductor substrate is shown, which includes an example precision component, an example first axial stress sensor, and an example second axial stress sensor.

[0018] Figure 14 This is a layout diagram showing an example Wheatstone bridge structure including two example X-axis sensors, each with a corresponding example accuracy component.

[0019] Figure 15 This is a layout diagram showing an example stress gradient of an example integrated circuit formed on a semiconductor substrate. Detailed Implementation

[0020] In the accompanying drawings, similar reference numerals indicate similar elements, and various features need not be drawn to scale.

[0021] The continuous advancements in semiconductor manufacturing have accelerated the integration, functionality, and operating speed of electronic devices. Electronic devices include electronic / electrical components (such as resistors and transistors) that can be formed on semiconductor substrates. At least some of the advancements in semiconductor manufacturing include the use of photolithography processes to form increasingly smaller structures, allowing the formation of electronic device structures using less space on the semiconductor substrate. As these structures become smaller, the electrical performance of the formed components can be more significantly affected by a given mechanical stress encountered by the semiconductor substrate.

[0022] In some examples, the applied mechanical stress affects various parameters of at least some semiconductor components depending on the direction of the applied mechanical stress. For example, the parameters of an operating circuit can change according to the orientation of the stress (e.g., force vector) applied to the crystal structure of the semiconductor substrate.

[0023] The semiconductor substrate can be a semiconductor wafer (e.g., a silicon wafer, which may be referred to as a "wafer"), which can be formed by laterally slicing (e.g., by sawing) a single crystal rod (e.g., a bundle of crystals formed from seeds). During subsequent processing steps performed using the semiconductor wafer, the semiconductor wafer retains the crystal structure of the single crystal rod, such that the semiconductor wafer can exhibit electromechanical properties as a function of the geometry of the crystal structure.

[0024] The surface of a wafer may include exposed crystallographic planes of atoms / molecules arranged (e.g., grown in crystalline form) within the wafer. After exposing the selected wafer surface, semiconductor devices may be formed (e.g., including penetrating into) the wafer surface, wherein the orientation of the semiconductor devices relative to the crystallographic planes of the semiconductor substrate is aligned on the selected wafer surface.

[0025] Depending on the substituent material(s) used to form the crystal, the three-dimensional crystal structure of the formed crystal can include different planes (and crystal-aligned axes). The planes and axes of the formed crystal can be determined by the atomic or molecular properties of the substituent material chosen for growing the crystal. Specific planes in the structure can be represented using "Miller indices," which are described below using braces (e.g., curly braces, such as in the example "{100}").

[0026] Figure 1AThis is a top view of an example semiconductor wafer. Wafer 100A is an example p-type semiconductor wafer formed to include a master planarization plane. In this example, the master planarization plane is illustrated as a non-circular (e.g., straight) edge of wafer 100A. The orientation of the master planarization plane can be selected in response to the geometric characteristics of the crystal structure of wafer 100A. The master planarization plane can be used to orient wafer 100A during various stages of the manufacturing process such that structures can be formed on the wafer (e.g., near the wafer) with orientation relative to the crystal structure of the wafer. The top surface of wafer 100A is the {100} plane of the lattice of wafer 100A.

[0027] The exposed surface (e.g., the top surface) of the wafer does not need to be formed perfectly parallel to the {100} plane. Other semiconductor substituents having appropriate geometries (e.g., at the atomic or molecular level) for forming regular crystals with selected combinations of crystallographic planes can be used to form semiconductor wafers. Regular crystals can be sawed (e.g., sawed in a direction referencing one of the selected crystallographic planes) to form wafers, and the wafers can be processed to include different types of dopants (such as n-type or p-type dopants) distributed on portions of the wafer (e.g., such that the processed wafer includes electrical components formed in an orientation determined in response to one of the selected crystallographic planes).

[0028] Wafer 100A includes four crystallographic directions or axes, such as V, W, X, and Y. Each of the V, W, X, and Y axes lies in a plane of the top surface of wafer 100A (e.g., parallel to and / or coincident with the top surface of wafer 100A). Each of the V, W, X, and Y axes includes an orientation of the geometric properties of the crystal structure of wafer 100A.

[0029] The orientation of the axes can be described using three-dimensional point unit vectors, such as [xyz]—used to describe target points relative to the origin (e.g., the origin chosen relative to the geometric characteristics of the crystal structure of wafer 100A). The W-axis is oriented perpendicular to the main plane and coincides with the

[110] crystal axis, and the V-axis is oriented parallel to the main plane. The X-axis is oriented at a 45-degree angle to the

[110] crystal axis (e.g., counterclockwise) and is oriented parallel to (e.g., coincident with) the

[100] crystal axis. The Y-axis is oriented at a 90-degree angle to the X-axis. In the examples described below, various circuit structures with linear features are formed, which are typically oriented parallel to or perpendicular to the main plane of the wafer on which the various circuit structures are formed.

[0030] This document uses an illustrative reference to the

[100] crystal axis to describe various stress sensors (such as piezoelectric devices) (other alignments or orientations relative to the various crystal axes are possible). The piezoresistive coefficient may be expressed herein as “π” (e.g., the Greek letter pi), where the piezoresistive coefficient indicates the resistive sensitivity to stress applied to a piezoresistive component along a particular axis. For example, stress occurring along the X-axis (e.g., stress applied or decomposed into vector components) may be described herein as occurring longitudinally along the

[100] crystal axis (e.g., with a piezoresistive coefficient π having a first axial orientation). LONG The stress occurring along the Y-axis can be described in this paper as occurring transversely to the

[100] crystal axis (e.g., with a second axial piezoresistive coefficient π). TRAN Because, for example, not all crystal axes of any lattice must be orthogonal to each other (e.g., and can be orthogonal or hexagonal), there may be different angles (including orthogonal or non-orthogonal angles) between the piezoresistive coefficients (along different axes) and / or selected axes at two, three or more stress sensors.

[0031] Figure 1B yes Figure 1A An orthogonal view of an example cross-section of an example semiconductor wafer. Part 100B is an example portion oriented relative to the orthogonal X, Y, and Z axes. The X and Y axes extend within a plane of wafer 100A (e.g., a plane parallel to wafer 100A), and as shown... Figure 1A The orientation is shown, while the Z-axis extends vertically through the plane of wafer 100A.

[0032] Stress occurring within a portion of 100B (e.g., applied stress) is denoted herein by the symbol “σ” (e.g., the Greek letter sigma). Stress can be expressed as a tensor value with six components: three normal stresses (e.g., shown as σ). xx σ yy σ zz ) and three shear stresses (e.g., σ XY σ XZ σ YZ (Not specifically shown in this article). The three normal stresses and three shear stresses can each affect at least one parameter of the performance (e.g., electrical performance) of a device such as an analog circuit formed on a portion 100B (e.g., a piezoelectric material).

[0033] Typically, because packaged integrated circuit chips are often constructed and formed in layers along the X, Y, and Z axes, each normal stress can be measured more easily than any shear stress. For example, two stress components (e.g., σ) xx and σ yy Located in the plane of wafer 100A, and can be measured by corresponding devices extending longitudinally along the X-axis or Y-axis. Furthermore, for example, the normal stress component (e.g., σ)zz It extends perpendicular to the plane of wafer 100A and can be measured by devices formed as a “stack” extending vertically along the Z-axis. The shear stress component typically has an order of magnitude of lower-order operating effects (e.g., compared to normal stress operating effects) and is negligible in various end applications.

[0034] Figure 1C yes Figure 1B An orthogonal view of an example cross-section of an example semiconductor wafer. Part 100C is an example portion of a semiconductor substrate orthogonally oriented along the X, Y, and Z axes relative to part 100B.

[0035] Part 100C includes an X element 110, a Y element 120, and a Z element 130. The X element 110 includes contacts 111 and 112, and a first shaft member 113 (e.g., an X-axis member). The Y element 120 includes contacts 121 and 122, and a second shaft member 123 (e.g., a Y-axis member). The Z element 130 includes contacts 131 and 132, third shaft members 133 and 134 (e.g., Z-axis members), and a connecting member 135 (which may include relatively low resistance compared to the effective resistance of the third shaft members 133 and 134). The Z element 130 may be arranged such that the connecting member is parallel to the second shaft member 123 (as shown) or parallel to the first shaft member 113 (not shown). Furthermore, by combining (e.g.) a second axis member and a third axis member (e.g., a stress sensing member) within a single-direction stress sensor, other orientations of the element (e.g., non-orthogonal to the corresponding orientations of other elements) can be achieved, making it possible to detect and compensate for non-orthogonal stresses (e.g., shear stress) more accurately.

[0036] Each of the first, second, and third axis members may include an N+ dopant and / or a P+ dopant, such that a channel (e.g., a resistive channel) can be formed during operation. The first axis member 113 is arranged to change its effective resistance in response to a change in the first axis stress vector, the second axis member 123 is arranged to change its effective resistance in response to a change in the second axis stress vector, and the third axis members 133 and 134 are each arranged to change their effective resistance in response to a change in the third axis stress vector. In the example described below, the directional stress sensor may include a resistor pair comprising a first axis N-type resistor electrically coupled (e.g., connected) to a second axis N-type resistor. The resistor pair may be formed on a P-type wafer such that the first axis is oriented parallel to the X-axis.

[0037] Figure 2This is a top view of an example wafer including an example first axial stress sensor. Wafer 200 includes an analog front-end 202 (AFE), a first axial stress sensor 210, a precision device 220, a coupler 230, a compensation circuit 240, and an analog circuit 250. Parts (e.g., portions or entire portions) of the compensation circuit 240 and the analog circuit 250 may be formed within and / or between the various components of the analog front-end 202, and are not necessarily considered as "parts" of the analog front-end 202.

[0038] Analog front-end 202 is arranged to generate a first analog compensation signal at the output of the first analog front-end in response to a precision electrical signal (e.g., which may be the signal to be compensated) and a first axis sensing signal. The precision electrical signal may be the output of precision device 220, and the first axis sensing signal may be the output of first axis stress sensor 210. (Refer to below...) Figures 4 to 8 Describe an example of a simulated front-end.

[0039] The first axial stress sensor 210 is an example stress sensor, which includes a set (e.g., a pair) of resistors XR coupled in series. TRAN and XR LONG Resistor XR TRAN and XR LONG Formed on the surface of wafer 200, enabling XR TRAN and XR LONG Lateral orientation (e.g., arranged orthogonally to each other). Wafer 200 is an example wafer such as wafer 100A.

[0040] The first axial stress sensor 210 includes a series-coupled resistor XR. TRAN and resistor XR LONG Compared to resistor XR, which primarily responds to changes in a second stress perpendicular to the first applied stress (e.g., stress applied along the Y-axis), TRAN and resistor XR LONG The series resistors are arranged to change primarily in response to stress applied along a first orientation (e.g., along a longitudinal axis, such as the X-axis). The operation of an example sensing resistor is described in commonly assigned U.S. Patent No. 10,352,792, entitled “Device and Method for On-Chip Mechanical Stress Sensing,” published July 16, 2019, which is incorporated herein by reference in its entirety.

[0041] In one example, resistor XR LONG It is a first axial stress-sensing resistor, which includes a first axial conductor arranged to conduct a first orientation current flowing primarily along the longitudinal direction of the crystal axis

[100] (e.g., along the X-axis). Resistor XRTRAN It is a second-axis stress-sensing resistor, which includes a second-axis conductor arranged to conduct a second orientation current that flows primarily transverse to the crystal axis (e.g., along the Y-axis).

[0042] As described below, (e.g., compared to a change in force applied along the Y-axis) resistor XR LONG and resistor XR TRAN Series coupling is used to generate a resistance change in response to a force applied along the X-axis. In one example, resistor XR LONG Arranged relative to the applied σ xx Stress includes a larger piezoresistive coefficient, and resistance XR TRAN Arranged relative to the applied σ yy Stress includes a larger piezoresistive coefficient.

[0043] Resistor XR LONG This can be formed by implanting a low dose of N-type dopant into multiple lateral conductors aligned longitudinally or laterally to a selected crystal axis (e.g., the X-axis), providing a substantially constant resistance along the lateral conductors. The lateral conductors are connected by longitudinal conductors that conduct current in a direction substantially perpendicular to the selected axis, but with minimal increase in resistance, making the resistor XR... LONG The total resistance is (e.g., primarily and / or largely dependent on) the stress applied by the orientation parallel to the transverse conductor. In various examples, XR LONG The combined length of the longitudinal conductors is XR LONG The combined length of the transverse conductors is seven times. For example, these directions are perpendicular (e.g., substantially perpendicular) when the stress-induced effect of the first axial stress sensor 210 is reduced in response to the output signal of the stress sensor in the corresponding direction.

[0044] Resistor XR TRAN It can be used to form a resistor XR LONG Formed in a similar manner, for example, resistor XR LONG This can be achieved, for example, by selecting with respect to resistor XR. TRAN The selected axis (e.g., X-axis) is different from the chosen axis (e.g., Y-axis) to form the shape. In various examples, XR... LONG The combined length of the transverse conductors is XR TRAN One-seventh of the combined length of the longitudinal conductors. In various examples, resistor XR LONG The combined length of the transverse conductor and the resistor XR TRAN The ratio of the combined lengths of the longitudinal conductors can be in response to the resistor XR. LONG and resistor XR TRAN The ratio is selected based on the parameters of the sensor.

[0045] In this example, resistor XR LONG Oriented to make resistor XR LONG The main direction of the current in the middle is longitudinal. <100> Crystal axis, and resistor XR TRAN Oriented to make resistor XR TRAN The main direction of the current in the middle is transverse to <100> Crystal axis. For an N-type resistor implemented in silicon and oriented along the

[100] crystal axis, the longitudinal piezoresistive coefficient π LONG It is -102.2% / GPa, and the transverse piezoresistive coefficient π TRAN It is 53.4% / GPa. In various examples, the piezoresistive coefficient can also be determined empirically by measuring the response of the corresponding sensor (e.g., which includes an in-plane resistor) to the applied stress vector.

[0046] Resistor XR LONG and resistor XR TRAN The corresponding resistance varies in response (e.g., as a function) to both the corresponding piezoresistive coefficient and (if present) the longitudinal and transverse stresses. For example:

[0047] ΔXR LONG =R·(π) LONG ·σ XX +π TRAN ·σ YY (1)

[0048] ΔXR TRAN =R·(π) TRAN ·σ XX +π LONG ·σ YY (2)

[0049] Where ΔXR LONG It is the resistance change along the y-axis, ΔXR TRAN It is along Figure 2 The resistance change along the x-axis is shown, where R is the resistance in the resistor when no stress is applied.

[0050] In one example, resistor XR LONG and resistor XR TRAN Selected to be similarly doped and have similar widths, and resistor XR LONG Length and resistor XR TRAN The ratio between lengths (e.g., LXR) LONG Divide by LXR TRAN The value α was chosen to be equal to the value α(alpha). The value α was chosen to be equal to -1*(π). LONG / π TRANThis allows, for example, the relative length of the resistors to be used to eliminate relative stress encountered on the substrate. In one such example, the value α is chosen (e.g., determined) to be 53.4 / 102.2 or approximately 0.52.

[0051] As described above, resistor XR LONG and resistor XR TRAN A series-coupled piezoelectric material is arranged on wafer 200, allowing current to flow through resistor XR. LONG and resistor XR TRAN Both, resistor XR LONG and resistor XR TRAN Together, they form the first axial stress sensor 210. Since the resistance of the series-coupled resistors can be expressed as the sum of their respective resistances, the resistance of the first axial stress sensor 210 along the X-axis can be expressed as:

[0052] ΔR XX =α·ΔXR LONG +ΔXR TRAN (3)

[0053] By choosing a value α to reflect π TRAN With π LONG The ratio between them, mathematically eliminating the value σ YY , so that ΔR XX Become with σ XX Proportional. When the example is implemented in silicon:

[0054] ΔR XX =R·(2.914-140.78*10) -11 Pa -1 ·σ XX (4)

[0055] Wafer 200 includes a precision device 220 disposed thereon (e.g., formed or otherwise placed on a substrate). Precision device 220 is coupled to a first axial stress sensor 210 (see reference below). Figure 4The X-axis directional stress sensor 440 is described. Precision device 220 includes precision components, such as a calibrated resistor. This calibrated resistor may be a finely tuned and / or finely tuned resistor or a finely tuned semiconductor structure that provides accurate (e.g., calibrated) electrical charge, allowing the precision components to provide accurate electrical functionality to precision device 220. In one example, a finely tuned reference resistor (during packaging or operation) is finely adjusted to scale the voltage or current of the directional stress sensor, such that the output current or voltage of the calibrated directional stress sensor matches (e.g., cancels, offsets, and / or reduces) the effect of the stress vector on one or more performance parameters of the analog circuit to be compensated. The precision components are disposed on a piezoelectric material and include precision electrical characteristics (e.g., performance parameters) that change in response to stress applied to the piezoelectric material. One or more stresses applied to the substrate can alter (e.g., adversely affect) the accuracy of the precision electrical characteristics. As described below, a first axial stress sensor 210 can generate an indication of directional stress, allowing the effects of stress on precision device 220 to be compensated (e.g., via compensation circuitry 240). The precision device 220 may include analog circuitry 250 (e.g., which may have operating parameters that can be adversely affected by variations in the stress vector in the piezoelectric material of the wafer 200).

[0056] In one example, the analog front end 202 includes a first axial stress sensor 210 (e.g., an X-axis stress sensor) disposed on a piezoelectric material of wafer 200 and coupled to a precision component (e.g., precision device 220). The first axial stress sensor may be coupled to the precision component for electrical coordination via analog signals (e.g., as referenced below). Figure 4 The X-axis stress sensor 440 is coupled within a Wheatstone bridge. The first axial stress sensor includes a first transverse stress sensing resistor (e.g., XR). TRAN The first longitudinal stress sensing resistor (e.g., XR) is coupled in series. LONG The first longitudinal stress-sensing resistor includes a longitudinal conductor arranged longitudinally to the crystal axis, and the first transverse stress-sensing resistor includes a transverse conductor arranged transversely to the crystal axis. The ratio of the resistance of the first stress-sensing resistor to the resistance of the second stress-sensing resistor is proportional to the ratio of the first piezoresistive coefficient to the second piezoresistive coefficient (e.g., see Equations 1 to 3 described above). The first axial stress sensor is arranged to generate a first-axis (e.g., X-axis) sensing signal in response to a first-axis resultant force (e.g., longitudinal resultant force) of the stress vector applied to the piezoelectric material. In one example, the ratio of the resistance of the transverse component of the first axial stress sensor to the resistance of the longitudinal component of the first axial stress sensor is substantially equal to the ratio of the first piezoresistive coefficient to the second piezoresistive coefficient.

[0057] See below for reference Figure 4In the described example, the simulation front end 402 includes a second axial stress sensor (e.g., a Y-axis stress sensor) disposed on a piezoelectric material of the wafer and arranged to generate a second axial sensing signal in response to a second axial resultant force of a stress vector applied in the piezoelectric material. (See below for reference.) Figure 4 , Figure 5 , Figure 10 and Figure 12 An example describing a Y-axis stress sensor.

[0058] In another example (for example, using the above about...) Figure 1C The analog front end 402 further includes a third-axis stress sensor (e.g., a Z-axis stress sensor) disposed on a piezoelectric material of the wafer and arranged to further generate a third-axis sensing signal in response to the third-axis resultant force of the stress vector applied in the piezoelectric material.

[0059] One or more stresses applied to wafer 200 may include stresses generated by heat-generating components during operation, as well as stresses that may be applied after calibration of precision components (e.g., fine-tuning a adjustable resistor). Post-calibration applicable stresses may occur in response to subsequent manufacturing, packaging, and insertion processes (e.g., mounting on a carrier or printed circuit board). Such stresses may be caused by relatively unsuitable packaged components and applied heat (e.g., during soldering) and cooling (e.g., causing contraction of components with different coefficients of thermal expansion), resulting in stresses being applied to the substrate from different locations of each stress source.

[0060] The stress-induced electrical effect at various locations on the substrate can vary at each location in response to non-uniformly applied stress on the substrate. For example, the stress-induced electrical effect on a first region of the wafer can differ from that on a second region of the wafer (e.g., it varies with time and spatial magnitude). One or more stresses applied to the substrate can result in different local stress vectors across the entire substrate at the same point in time.

[0061] Local stress vectors that can affect the accuracy of the precision device 220 can be determined by positioning (e.g., forming) a portion of the first axial stress sensor 210 close to the precision device 220 (e.g., stress-sensitive portion). Positioning at least one directional stress sensor (e.g., one or more of the first axial stress sensors 210) close to the precision device 220 allows the detection of the magnitude of local (e.g., specific) stress vectors that adversely affect the precision operation of the precision device 220. As described below (e.g., refer to...) Figures 4 to 8In response to determining the magnitude of one or more stress vectors (e.g., one or two of the resolved orthogonal stress vectors that locally affect the operational accuracy of the precision device 220), the adverse effects of local stress vectors on the precision device 220 can be compensated for (e.g., offset or otherwise improved).

[0062] In various examples, a portion (e.g., the entire portion or a portion smaller than the entire portion) of the precision device 220 is located (e.g., formed on) the resistor XR. TRAN Part of the resistor XR LONG Between a portion of the resistor XR TRAN and resistor XR LONG The components are connected in series via coupler 230. In one example, coupler 230 is formed close to precision device 220. In one example, a portion of precision device 220 is positioned close to resistor XR. TRAN The first axial stress sensor 210 is located within the lateral length of the resistor XR. In one example, a portion of the precision device 220 is positioned close to the resistor XR. LONG The first axial stress sensor 210 extends along the longitudinal length. In one example, the resistor XR TRAN and resistor XR LONG Co-generated stress, which indicates (e.g., approximately) the stress generated by the resistor XR TRAN Part of the resistor XR LONG A portion of the precision components 220 encounters stress.

[0063] Wafer 200 includes compensation circuitry 240. In one example, compensation circuitry 240 includes a first input coupled to the output of analog front-end 202 (e.g., for generating a signal indicating the stress generated by the first axial stress sensor 210), a second input coupled to the output of analog circuitry 250 (which may output signals that may include operating parameters adversely affected by variations in the stress vector of wafer 200), and is arranged to generate a compensation signal at the first output of compensation circuitry in response to a compensation analog signal and the output signal of the analog circuitry. Reference is made below to, for example... Figure 4 The signal conditioner 420 discusses an example of generating a compensated output signal.

[0064] In various examples, resistor XR TRAN and resistor XR LONG Stress is generated collaboratively at the selected location on wafer 200 by sensing locally applied stress in a region adjacent to the selected location. In one example, resistor XR TRAN and resistor XR LONGThe stress is generated in coordination along a notional line that intersects (or is adjacent to) a portion of the precision device 220 (e.g., a precision component), such as within the lateral or longitudinal length.

[0065] Local stress vectors can independently and differently affect each of a plurality of precision devices on a common substrate. Where the accuracy of the output of at least one circuit on a wafer depends on the respective accuracy of each of the plurality of precision components, the accuracy of the output can be affected (e.g., adversely affected) by a reduction in the accuracy of any of the plurality of precision components. As described herein, co-locating the directional stress sensor described herein adjacent to (or otherwise mechanically and / or electrically coupled to) the respective precision component can improve the accuracy of the output, which depends on the accuracy of each respective precision component. Co-locating the respective directional stress sensor described herein adjacent to each precision component on which accuracy depends allows each dependent precision component to individually compensate for the stress effects encountered independently by each dependent precision component.

[0066] Figure 3 This is an example graph illustrating the response of an example circuit to independently applied X-dimensional and Y-dimensional normal stresses. Graph 300 is an example graph from the Springer journal, 2016, by M. Motz and U. Ausserlechner, entitled "Electrical Compensation of Mechanical Stress Drift in Precision Analog Circuits". Graph 300 indicates the percentage drift of the output frequency of a resistor / capacitor (RC) relaxation oscillator on a chip (e.g., a portion of a semiconductor wafer) to which an oscillator is structured in response to normal stress being applied.

[0067] Graph 300 shows the difference in the percentage of drift as a function of stress applied independently (e.g., not simultaneously) in two orthogonal directions. In this example, compared to the drift percentage caused by σ... YY The slope of the stress (e.g., stress applied along the Y-axis) indicates the circuit response compared to σ. xx Stress (e.g., stress applied perpendicular to the X-axis) indicates that the circuit response exhibits a significantly disproportionately large frequency drift. σ xx The slope of the stress response and σ YY The difference in the slopes of the stress response indicates a difference in sensitivity to orthogonally applied (e.g., orthogonally generated) mechanical stresses. Additionally, σ xx Stress causes frequency drift in the normally positive direction, while σ YYStress causes frequency drift in the normally negative direction.

[0068] Physical circuit for σ xx Stress and σ YY The actual stress response can vary depending on the orientation of the semiconductor design structure and the type and level of doping used to form the semiconductor design structure. Since the slope and drift direction (e.g.) of mechanical stress applied in different directions of the {100} plane differ, various techniques can be employed to help determine the σ produced by a mechanical force (e.g., a mechanical force applied from any direction) applied to a stress sensor or stress-sensitive circuit. xx Stress and σ YY The actual value of each stress.

[0069] In various conventional systems, separating σ xx Stress components and σ YY Stress components are sensed by their net sum (e.g., net sum σ). xx +σ YY ) and by sensing the net difference between the two (e.g., net difference σ) xx -σ YY This system can employ digital signal processing (which involves relatively complex circuitry) to isolate the signal against σ. xx Stress components and σ YY The value of each of the stress components is determined and the stress applied within the {100} plane is compensated (e.g., stress applied in any direction). Such a system may require additional power and substrate area.

[0070] This document describes an example stress compensation circuit configured to electrically eliminate one (e.g., at least one) of the orthogonal stress components, such that stress effects can be compensated without requiring mathematical calculations as a post-processing function (e.g., via a digital signal processor). In various examples described herein, the stress compensation circuit may be configured to generate a stress-regulated output and / or configured to correct at least one feedback signal in response to an indication (e.g., an orientation sensor reading) generated in response to at least one of a pair of orthogonal stress vectors. Example techniques described herein may include a stress-sensitive resistor, as described below, arranged to reduce (if not eliminate) at least one stress component (e.g., σ) in the analog domain. xx Or σ YY ).

[0071] Figure 4This is a schematic diagram of an analog front-end based on a Wheatstone bridge, used for stress compensation of analog signals. System 400 is an example system including a substrate 401, analog circuitry 410, signal conditioner 420, temperature sensor 430, a first axial stress sensor (e.g., X-axis stress sensor 440), an optional second axial stress sensor (e.g., Y-axis stress sensor 450), operational amplifiers 442 and 452 (e.g., each configured as a two-to-one converter).

[0072] Overall, system 400 includes a substrate 401 on which analog circuitry 410 is disposed. System 400 is configured to compensate for analog signals generated by analog circuitry 410, wherein the analog signals may be affected by stresses applied to the substrate 401 during operation (e.g., adversely affecting the image). System 400 includes an analog front end 402 (AFE) comprising directional stress sensors (as described above) for sensing stresses applied to the substrate 401 and for generating at least one compensated analog signal. Analog front end 402 includes directional stress sensors (e.g., X-axis directional stress sensor 440 and Y-axis directional stress sensor 450) configured to sense a first (e.g., X-axis) stress vector and a second (e.g., Y-axis) stress vector in the substrate 410, respectively, and to generate a compensated analog signal for each sensed stress vector. The system also includes a signal conditioner 420 (e.g., analog and / or digital signal compensation circuitry) for generating a compensation signal in response to at least one compensation analog signal and in response to an analog signal generated by analog circuitry 410 (e.g., which may be adversely affected by one or more stress vectors during operation). The signal conditioner 420 may be the compensation circuitry 240 as described above.

[0073] In various examples, analog circuitry 410 is adjacent to substrate 401 (e.g., formed in and / or on substrate 401) and configured to generate analog signals. Stress applied to substrate 401 can affect the operational stability of analog circuitry 410, such that the baseline operation of analog circuitry 410 is affected in response to directional forces (e.g., stress vectors) applied to substrate 401 (e.g., as a function of the directional forces applied to substrate 401). Deviation from baseline operation causes at least one electrical parameter of the generated analog signal to change from a base value (e.g., a value occurring during baseline operation) to a deviated value (e.g., a value occurring during operation during the application of force). Analog circuitry 410 can be circuitry such as one or more operational amplifiers, RC (resistor-capacitor) oscillators, bandgap reference voltage generators, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), analog front-ends (AFEs), and various sensors (e.g., for sensing temperature, pressure, humidity, and other physical quantities).

[0074] Signal conditioner 420 is arranged to receive an X-axis compensation signal (e.g., generated by X-axis stress sensor 440), a Y-axis compensation signal (e.g., generated by Y-axis stress sensor 450), and an optional temperature compensation signal (e.g., generated by temperature sensor 430), wherein signal conditioner 420 is arranged to generate a compensated analog signal in response to the received analog signal (e.g., having a deviation value caused by the stress vector), the orientation compensation signal, and the optional temperature compensation signal. In one example, the compensation signal includes a compensation value that is closer to the base value than the degree of closeness of the deviation value to the base value. The compensation signal can be a digital signal (e.g., digitally generated by a processor in response to sensor readings) or an analog signal (e.g., an analog signal generated in response to stress sensor readings).

[0075] In one example, substrate 401 includes circuitry and compensation circuitry comprising a piezoelectric material, a first axial stress sensor, a second axial stress sensor, and a piezoelectric material. The piezoelectric material may be included in substrate 401 such that deflection of substrate 401 (in response to physical stress) causes the piezoelectric material to flex. The piezoelectric material has a crystal axis (e.g., an X-axis), a first piezoresistive coefficient longitudinally to the crystal axis, and a second piezoresistive coefficient transversely to the crystal axis.

[0076] X-axis stress sensor 440 includes resistors Rrefxa, Rsense_xb, Rsense_xa, and Rrefxb arranged in a Wheatstone bridge to generate a differential signal Vsense_x at an intermediate node between a first branch and a second branch of the Wheatstone bridge. The differential signal Vsense_x indicates, for example, the average value of the X-axis stress vector sensed by resistors Rsense_xa and Rsense_xb, and is resistant to signal interference due to common-mode rejection. Resistors Rrefxa and Rsense_xb are coupled in series between a first power rail (e.g., VCC) and a second power rail (e.g., ground) (in the first branch), while resistors Rsense_xa and Rrefxb are coupled in series between the first and second power rails (in the second branch). In various examples, Rrefxa and Rsense_xb are coupled in series such that a first current flows through resistors Rrefxa and Rsense_xb, and resistors Rsense_xa and Rrefxb are coupled in series such that a second current flows through resistors Rsense_xa and Rrefxb.

[0077] In one example, the first stress sensor includes resistors Rrefxa, Rsense_xb, Rsense_xa, and Rrefxb. Resistor Rsense_xa is a first x-axis stress sensor, including a first terminal coupled to a first power rail and a second terminal coupled to a first precision component (e.g., Rrefxa), the first precision component also including a second terminal coupled to a second power rail. Resistor Rsense_xb is a second x-axis stress sensor, including a first terminal coupled to a second power rail and a second terminal coupled to a first terminal of a second precision component (e.g., Rrefxb), the second precision component also including a second terminal coupled to the first power rail.

[0078] Each of the sensing resistors Rsense_xa and Rsense_xb is a directional stress sensor, such as the first axial stress sensor 210 described above. In one example, the sensing resistor Rsense_xa (of the X-axis directional stress sensor 440) is a first first axial (e.g., X-axis) directional stress sensor, and the sensing resistor Rsense_xb (of the X-axis directional stress sensor 440) is a second first axial (e.g., X-axis) sensing element. See below for further details. Figure 12 The sensing resistors Rsense_xa can be arranged in series as X1R TRAN and X1R LONG The sensing resistors Rsense_xb can be arranged in series as X2R TRAN and X2R LONG Each directional stress sensor is arranged such that the first sensing resistor (X1R) LONG ) and the second stress sensing resistor (X1R) TRAN The ratio of the resistance of the resistor to the first piezoresistive coefficient (e.g., piezoresistive coefficient π). LONG ) and the second piezoresistive coefficient (e.g., piezoresistive coefficient π) TRAN The ratio is positive. In the example directional stress sensor, the second stress sensing resistor (e.g., X1R) TRAN The resistance of the first stress sensing resistor (e.g., X1R) is compared with that of the first stress sensing resistor. LONG The ratio of the resistances of the piezoresistive elements is essentially equal to the ratio of the first piezoresistive coefficient (e.g., along the longitudinal crystal axis) to the second piezoresistive coefficient (e.g., along the transverse crystal axis). For example, these ratios are essentially equal when the stress-induced effect of the analog circuit 410 is reduced in response to the output signals of the respective stress sensors.

[0079] Reference resistor Rrefxa may be included in precision device 1220, while reference resistor Rrefxb may be included in precision device 1222. In this way, the local stress applied to each reference resistor is sensed individually in response to the direction of each force, and thus, the resistance deviation caused by the stress of each reference resistor can be compensated individually and separately.

[0080] Each reference resistor, Rrefxa and Rrefxb, can be an example of a precision component. A precision component can be a component such as a tunable resistor or a tunable transistor (which may include tunable “finger”). In one example, the tunable resistor may be tunable (e.g., laser-tuned) before the substrate is packaged into a package (where the package material prevents further tunable tuning of the tunable resistor). The packaging and subsequent encapsulation processes may apply mechanical stress to the substrate, which can change the resistance of the tunable resistor (e.g., after a time when the tunable resistor is no longer available for tuning). The applied mechanical stress can be applied through temperature fluctuations encountered during mounting, soldering, roughing, thermal cycling, and operation. The systems and methods described herein (e.g., system 400) can reduce the cost, time, and layout area that may be encountered when attempting to calibrate the precision of a precision component to the level of precision initially calibrated (e.g., calibrated before packaging the precision component).

[0081] The X-axis stress sensor 440 generates a differential signal Vsense_X at the intermediate node of the first and second branches of the Wheatstone bridge. In one example, a first first-axis stress sensor (e.g., Rsense_xa), a second first-axis stress sensor (e.g., Rsense_xb), a first precision component (e.g., Rrefxa), and a second precision component (e.g., Rrefxb) are arranged in a Wheatstone bridge, wherein the first-axis sensing signal is a differential signal of the first-axis sensing signal, having a first end generated at the second terminal of the first x-axis stress sensor and a second end generated at the first terminal of the second x-axis stress sensor.

[0082] In one example, the differential signal Vsense_x can be buffered and / or converted into a single-ended Vsense_x signal by an operational amplifier 442 coupled to a feedback resistor Rfbx. The signal Vsense_x (whether single-ended or differential) is an X-axis compensation analog signal (e.g., used to compensate for the resultant force on the X-axis in response to a sensed stress vector). The X-axis compensation analog signal is coupled to a signal conditioner 420 (described below) for compensating the output of the analog circuit 410. In this example, the amplifier (e.g., operational amplifier 442) and the feedback resistor (e.g., feedback resistor Rfbx) are arranged to convert the differential signal of the first axis sense signal into a single-ended signal of the first axis sense signal.

[0083] The Y-axis stress sensor 450 is optional and can be included for calibration applications and end applications that include determining orthogonal stress vectors. The Y-axis stress sensor 450 includes resistors Rrefya, Rsense_yb, Rsense_ya, and Rrefyb, which are arranged in a second Wheatstone bridge to generate a differential signal Vsense_y at the intermediate node of the first and second branches of the second Wheatstone bridge. The Y-axis stress sensor 450 operates in a manner similar to the X-axis stress sensor 440, although the Y-axis stress sensor is arranged to generate an indication of the stress vector applied to the substrate 401 along the Y-axis. In one example, the sensing resistor Rsense_xa (of the X-axis stress sensor 440) is a first first-axis (e.g., X-axis) stress sensor, and the sensing resistor Rsense_ya (of the Y-axis stress sensor 450) is a first second-axis (e.g., Y-axis) stress sensor.

[0084] See below for reference Figure 12 The sensing resistors Rsense_ya can be arranged in series as Y1R TRAN and Y1R LONG The sensing resistors Rsense_yb can be arranged in series as Y2R TRAN and Y2R LONG Reference resistor Rrefya may be included by precision device 1220, while reference resistor Rrefyb may be included by precision device 1222. Each of reference resistors Rrefya and Rrefyb may be an example of a precision component.

[0085] The Y-axis stress sensor 450 generates a differential signal Vsense_y at the midpoint between the first and second branches of the second Wheatstone bridge. In one example, the differential signal Vsense_y can be buffered and / or converted into a single-ended Vsense_y signal by an operational amplifier 452 in cooperation with a feedback resistor Rfby. The signal Vsense_y (whether single-ended or differential) is a Y-axis compensation analog signal (e.g., used to compensate for the Y-axis resultant force in response to the sensed stress vector). The Y-axis compensation analog signal is coupled to a signal conditioner 420 (described below) for compensating the output of the analog circuit 410.

[0086] The signal conditioner 420 includes a first input coupled to the output of the analog front end 402 (e.g., for generating a compensated analog signal indicating the amount of stress generated by the X-axis stress sensor 440), a second input coupled to the output of the analog circuit 410 (which may output signals that may include operating parameters adversely affected by variations in the stress vector of the substrate 401), an optional third input coupled to the output of the analog front end 402 (e.g., for generating a compensated analog signal indicating the amount of stress generated by the Y-axis stress sensor 450), and an output that generates a compensated output signal in response to at least one compensated analog signal and the output analog signal of the analog circuit. An example of generating a compensated output signal is discussed below with reference to the signal conditioner.

[0087] Various examples of signal conditioner 420 may include a digital signal processor such as DSP 421. In examples of signal conditioner 420 including DSP 421, the signal conditioner may include analog-to-digital converters, such as ADC 422 for receiving an X-axis compensated analog signal and converting it to an X-axis compensated digital signal, ADC 423 for receiving an analog signal from analog circuit 410 and converting it to an output digital signal of the analog circuit, ADC 424 for receiving a Y-axis compensated analog signal and converting it to a Y-axis compensated digital signal, a digital-to-analog converter (DAC) for converting a digital compensated output signal to an analog compensated output signal, and ADC 426 for receiving an analog temperature signal from temperature sensor 430 and converting it to a digital temperature signal. DSP 421 is arranged to generate a digital compensated output signal in response to the X-axis compensated digital signal, an optional digital temperature signal, the output digital circuit of analog circuit 410, an optional Y-axis compensated digital signal, and an optional digital temperature signal. Other examples of signal conditioner 420 do not require the inclusion of digital circuitry, allowing the compensation circuitry to be compensated solely by analog circuitry.

[0088] In at least one example, DSP 421 may be arranged to provide measurements for performing fine-tuning, correction, and / or calibration of precision components. In one example, the DSP (e.g., via ADC 422) may determine a voltage generated in response to a fine-tunable resistor, such that a fine-tuning parameter can be generated in response to the determined voltage, and the fine-tunable resistor may then be fine-tuned. In one example, the DSP (e.g., via ADC 422) may determine a voltage generated in response to a fine-tuned resistor, such that a selected voltage of at least one power rail can be determined in response to the determined voltage, and applied to the fine-tuned resistor. In one example, the DSP (e.g., via ADC 422) may determine a voltage generated in response to a fine-tuned resistor, such that a selected voltage of at least one power rail can be determined in response to the determined voltage, and applied to the fine-tuned resistor. In one example, the DSP (e.g., via ADC 422) may determine a voltage generated in response to a fine-tuned resistor, such that a selected voltage can be determined and applied to the circuit for stress and / or temperature compensation of the circuit. In various examples, the DSP 421 may be arranged to execute instructions from a memory (not shown) to determine higher-order (e.g., nth-order) coefficients, thereby more finely compensating the analog output of the analog circuit 410 for various stresses encountered in the substrate 401.

[0089] Figure 5 This is a schematic diagram of an example Wheatstone bridge-based analog front end for feedback-based stress compensation of analog signals. System 500 is an example system including a substrate 501, analog circuitry 510, a signal conditioner 520, a temperature sensor 430, a first axial stress sensor (e.g., an X-axis stress sensor 440), an optional second axial stress sensor (e.g., a Y-axis stress sensor 450), operational amplifiers 442 and 452 (e.g., each configured as a two-to-one converter). System 500 operates in a manner similar to System 400, although analog circuitry 510 is arranged to generate a compensation feedback signal in response to at least one compensation analog signal, and analog circuitry is arranged to output an analog signal in response to the compensation feedback signal.

[0090] Various sensor circuits (e.g., sensor circuits 402, 602, 702, 802, and 950) can be coupled to various circuits (e.g., circuits external to a given sensor circuit), wherein such external circuitry may include passive components (e.g., resistors and capacitors) and / or active analog circuitry (e.g., DACs, transistors, and operational amplifiers) for driving (or otherwise operating) the sensor. The electrical parameters of one or more components of the external circuitry are also affected by the applied stress vector, thereby the signal generated for driving the sensor circuitry is also affected by the applied stress (such that the effects of the stress are combined by the direct application to the stress sensor and by introducing higher-order effects through the influence of the signal applied to the stress sensor). This combination of stress vector effects leads to higher-order effects, thereby reducing the accuracy of sensor readings. In response to the stress-sensing signal fed back to the sensor circuitry (e.g., by coupling as a negative feedback signal), this higher-order effect can be compensated for (e.g., reduced), such that the feedback stress-sensing circuitry can reduce the combination of these higher-order effects (e.g., thereby improving the accuracy of the sensor readings). In one example, the compensation signal (e.g., the stress-corrected Vref signal) may be substantially the same as the input signal (e.g., the nominal Vref signal) received by at least one element coupled to (e.g., included) the sensor circuitry.

[0091] The following is for reference. Figures 6 to 8 This describes an example AFE used to generate Vsense_x and Vsense_y signals for stress compensation.

[0092] Figure 6 This is a schematic diagram of an example operational amplifier-controlled current source for stress compensation of analog signals. System 600 is an example system including a substrate 601, an analog front end 602, and a compensation circuit 650.

[0093] Analog front-end 602 includes DAC 610, operational amplifier 620, transistor Qrefx, transistor Qsense_x, (adjustable) resistor Rrefx, and resistor Rsense_x. Operational amplifier 620 is arranged to control the current used to generate the analog compensation signal Vsense_x in response to resistor Rrefx (e.g., a precision component). Resistor Rrefx is a precision component such as an adjustable or fine-tuning resistor and has a first terminal coupled to the drain of transistor Qrefx and a second terminal coupled to a second power rail. Resistor Rrefx generates a voltage at the first terminal of Rrefx in response to a controlled current flowing from transistor Qrefx. The base of transistor Qrefx is coupled to the output of operational amplifier 620. Operational amplifier controls the current of transistor Qrefx in response to the voltage generated at the first terminal of resistor Rrefx and the output voltage of DAC 610. The output voltage of DAC 610 is generated in response to a reference voltage (e.g., Vref) and a temperature indication (e.g., a digital temperature value). Temperature indication can be used to control the temperature sensitivity of resistor Rsense_x and the temperature-dependent offset drift of compensation circuit 650 (e.g., it may be an oscillator). The output of operational amplifier 620 is also coupled to transistor Qsense_x such that the current flowing from transistor Qrefx is mirrored (e.g., proportionally mirrored) by transistor Qsense_x. The drain of transistor Qsense_x is coupled to a first terminal of resistor Rsense_x. Resistor Rsense_x is a first axial stress sensor, which further includes a second terminal coupled to a second power rail. Resistor Rsense_x generates a voltage Vsense_x (e.g., a compensation analog signal) at the first terminal of Rsense_x in response to a controlled current flowing from transistor Qsense_x and in response to the longitudinal resultant force of the stress vector applied in the piezoelectric material of substrate 601.

[0094] The analog front end 602 also includes a DAC 630, an operational amplifier 640, a transistor Qrefy, a transistor Qsense_y, a (tunable) resistor Rrefy, and a resistor Rsense_y. The operational amplifier 640 is arranged to control the current used to generate the analog compensation signal Vsense_y in response to the Rrefy resistor (e.g., a precision component). The resistor Rrefy is a precision component, such as a tunable or adjustable resistor, and has a first terminal coupled to the drain of the transistor Qrefy and a second terminal coupled to a second power rail. The resistor Rrefy generates a voltage at the first terminal of Rrefy in response to a controlled current flowing from the transistor Qrefy. The base of the transistor Qrefy is coupled to the output of the operational amplifier 640. The operational amplifier 640 controls the current of the transistor Qrefy in response to the voltage generated at the first terminal of the resistor Rrefy and the output voltage of the DAC 630. The output voltage of the DAC 630 is generated in response to a reference voltage (e.g., Vref) and a temperature indication (e.g., a digital temperature value). Temperature indication can be used to control the temperature sensitivity of resistor Rsense_y and the temperature-dependent offset drift of compensation circuit 650 (e.g., it may be a temperature-sensitive oscillator). The output of operational amplifier 640 is also coupled to transistor Qsense_y such that the current flowing from transistor Qrefy is mirrored (e.g., proportionally mirrored) by transistor Qsense_y. The drain of transistor Qsense_y is coupled to a first terminal of resistor Rsense_y. Resistor Rsense_y is a second axial stress sensor, which further includes a second terminal coupled to a second power rail. Resistor Rsense_y generates a voltage Vsense_y (e.g., a compensation analog signal) at the first terminal of Rsense_y in response to a controlled current flowing from transistor Qsense_y and in response to the lateral resultant force of the stress vector applied in the piezoelectric material of substrate 601.

[0095] The compensation circuit 650 is coupled to receive Vsense_x and Vsense_y analog compensation signals from the analog front end 602, and generates a compensated analog signal in response to the Vsense_x and Vsense_y analog compensation signals (and optionally in response to a temperature indication).

[0096] Figure 7 This is a schematic diagram of an example operational amplifier controlled by an amplifier for stress compensation of analog signals. System 700 is an example system including a substrate 701, an analog front end 702, and a compensation circuit 750.

[0097] The analog front end 702 includes a DAC 710, an operational amplifier 720, a (fine-tunable) resistor Rrefx, and a resistor Rsense_x. The operational amplifier 720 is arranged as a non-inverting amplifier to generate an amplified Vsense_x analog compensation signal in response to the ratio of the value of resistor Rsense_x to the value of resistor Rrefx. In one example, the voltage of Vsense_x is equal to Vref*(1+Rsense_x / Rrefx). Resistor Rrefx is a precision component such as a fine-tunable or adjustable resistor and has a first terminal coupled to a second power rail and a second terminal coupled to the inverting input of operational amplifier 720. Resistor Rsense_x is coupled between the output of operational amplifier 720 and the non-inverting input of operational amplifier 720, causing the output of operational amplifier 720 to be controlled in response to the longitudinal resultant force of the stress vector applied in the piezoelectric material of substrate 701. The non-inverting input of operational amplifier 720 is coupled to the output of DAC 710 (which is coupled to receive the Vref signal and temperature indication), so that the temperature indication can be used to control the temperature sensitivity of resistor Rsense_x and the temperature-dependent offset drift of compensation circuit 750 (e.g., which may be an oscillator).

[0098] The analog front end 702 also includes a DAC 730, an operational amplifier 740, a (tunable) resistor Rrefy, and a resistor Rsense_y. The operational amplifier 740 is arranged as a non-inverting amplifier to generate an amplified Vsense_y analog compensation signal in response to the ratio of the value of resistor Rsense_y to the value of resistor Rrefy. In one example, the voltage of Vsense_y is equal to Vref*(1+Rsense_y / Rrefy). Resistor Rrefy is a precision component such as a tunable or fine-tuning resistor and has a first terminal coupled to a second power rail and a second terminal coupled to the inverting input of operational amplifier 740. Resistor Rsense_y is coupled between the output of operational amplifier 740 and the non-inverting input of operational amplifier 740 such that the output of operational amplifier 740 is controlled in response to the lateral resultant force of the stress vector applied in the piezoelectric material of substrate 701. The non-inverting input of operational amplifier 740 is coupled to the output of DAC 730 (DAC 730 is coupled to receive the Vref signal and the temperature indication), such that the temperature indication can be used to control the temperature sensitivity of resistor Rsense_y and the temperature-dependent offset drift of compensation circuitry 750 (e.g., which may be an oscillator). In one example, operational amplifier 740 is arranged to generate an amplified analog compensation signal in response to the ratio of the value of a first axial stress sensor to the value of a precision component.

[0099] The compensation circuit 750 is coupled to receive Vsense_x and Vsense_y analog compensation signals from the analog front end 702, and generates a compensated analog signal in response to the Vsense_x and Vsense_y analog compensation signals (and optionally in response to a temperature indication).

[0100] Figure 8 This is a schematic diagram of an example current-controlled current source for stress compensation of analog signals. System 800 is an example system including a substrate 801, an analog front-end 802, and a compensation circuit 850.

[0101] Analog front-end 802 includes a current source 810, an operational amplifier 820, a resistor Rsense_x, and a (fine-tunable) resistor Rrefx. The analog front-end (e.g., 802) includes a current source 822 arranged to generate a source current such that an analog compensation signal (e.g., Isense_x) is generated in response to the source current and in response to a difference (e.g., a resistance change) between resistor Rsense_x (e.g., an x-axis stress sensor) and resistor Rrefx (e.g., a first precision component). Resistor Rsense_x includes a first terminal coupled to the output of current source 810 and the inverting input of operational amplifier 820, and a second terminal coupled to a second power rail. In one example, current source 810 is a temperature-dependent current, reducing the temperature-dependent effect of resistor Rsense_x. The output of operational amplifier 820 is coupled to the gate of transistor Qrefx, such that the operational amplifier controls the source-to-drain current of transistor Qrefx. The drain of transistor Qrefx (which is a non-controlled terminal) is coupled to the non-inverting input of operational amplifier 820 and a first terminal of resistor Rrefx, which includes a second terminal coupled to a second power rail. The voltage at the non-inverting input of operational amplifier 820 is generated in response to the source-to-drain current of transistor Qrefx and the resistance of resistor Rrefx, such that the output of operational amplifier 820 is controlled in response to the difference between resistor Rsense_x (e.g., an x-axis stress sensor) and resistor Rrefx (e.g., a first precision component), and that the output of operational amplifier 820 is controlled in response to the longitudinal resultant force of the stress vector applied in the piezoelectric material of substrate 801. The output of operational amplifier 820 is also coupled to transistor Qscale_x such that the current flowing from current source 822 is mirrored (e.g., proportionally mirrored) by transistor Qscale_x. In one example, the output of current source 822 is an analog compensation signal (e.g., Isense_x) coupled to a first input of compensation circuit 850.

[0102] The analog front end 802 also includes a current source 830, an operational amplifier 840, a resistor Rsense_y, and a (fine-tunable) resistor Rrefy. The analog front end (e.g., 802) includes a current source 842 arranged to control the current used to generate an analog compensation signal (e.g., Isense_y) in response to a difference (e.g., a resistance change) between resistor Rsense_y (e.g., a y-axis stress sensor) and resistor Rrefy (e.g., a first precision component). Resistor Rsense_y includes a first terminal coupled to the output of current source 830 and the inverting input of operational amplifier 840, and a second terminal coupled to a second power rail. In one example, current source 830 is a temperature-dependent current, such that the temperature-dependent effect of resistor Rsense_x is reduced. The output of operational amplifier 840 is coupled to the gate of transistor Qrefy, such that the operational amplifier controls the source-to-drain current of transistor Qrefy. The drain of transistor Qrefy (which is a non-controlled terminal) is coupled to the non-inverting input of operational amplifier 840 and a first terminal of resistor Rrefy, which includes a second terminal coupled to a second power rail. The voltage at the non-inverting input of operational amplifier 840 is generated in response to the source-to-drain current of transistor Qrefy and the resistance of resistor Rrefy, such that the output of operational amplifier 840 is controlled in response to the difference between resistor Rsense_y (e.g., a y-axis stress sensor) and resistor Rrefy (e.g., a first precision component), and that the output of operational amplifier 840 is controlled in response to the lateral resultant force of the stress vector applied in the piezoelectric material of substrate 801. The output of operational amplifier 840 is also coupled to transistor Qscale_y such that the current flowing from current source 842 is mirrored (e.g., proportionally mirrored) by transistor Qscale_y. In one example, the output of current source 842 is an analog compensation signal (e.g., Isense_y) coupled to a second input of compensation circuit 850.

[0103] The compensation circuit 850 is coupled to receive the Isense_x and Isense_y analog compensation signals from the analog front end 802, and generates a compensated analog signal in response to the Isense_x and Isense_y analog compensation signals (and optionally in response to a temperature indication). See below for reference. Figure 9 The stress-related currents can be combined to generate a combined analog compensation signal (e.g., current) that indicates a scalar of the combined longitudinal and transverse stresses sensed in the substrate 801.

[0104] Examples of circuits capable of compensating substrate stress include operational amplifiers (e.g., operational amplifiers included in stress compensation circuits, such as operational amplifiers 442, 452, 620, 640, 720, 740, 820, and 840), RC oscillators, current and voltage reference generators (e.g., bandgap voltage reference generators), ADCs (e.g., including ADCs 422, 423, and 424), DACs (e.g., DACs 425, 610, 630, 710, and 730), AFEs (e.g., including analog front-ends 402, 602, 702, and 802), and sensors (e.g., temperature and humidity sensors). The power and layout requirements of the compensation circuitry can be reduced by sharing, for example, the directional stress sensor signal / quantity used for the circuit to be compensated, and circuitry (e.g., operational amplifiers) arranged to compensate for the circuit to be compensated and / or the signals generated by the circuit to be compensated.

[0105] Figure 9 It is coupled to Figure 8 A schematic diagram of an example stress-compensated bandgap reference circuit with at least one example current-controlled current source. System 900 is an example system including substrate 801, current source 822, current source 842, and bandgap reference circuit 950 (e.g., a compensated bandgap voltage reference circuit).

[0106] The compensated bandgap reference circuit 950 is an example of the compensation circuit 850. The output signal of the bandgap reference circuit 950 (and the operation of a portion of the bandgap reference circuit 950 itself) can be compensated by injecting Isense_x and Isense_y analog compensation signals into the output node (e.g., output terminal) of the bandgap reference circuit. As described below, the output terminal may be included by compensation circuitry arranged to generate a combined analog compensation signal in response to the first axis sensing signal and the second axis sensing signal.

[0107] The bandgap reference circuit 950 includes a pair of matched transistors QH1 and QHN, wherein the gates of transistors QH1 and QHN are jointly driven and controlled by the output signal of an operational amplifier. The sources of transistors QH1 and QHN are coupled to a first power rail such that a first current flows from the drain of transistor QH1 and a second current flows from the drain of transistor QHN, wherein the first and second currents are substantially equal. The first current is conducted through the emitter of transistor QB1, and the second current is conducted through the emitter of transistor QBN, wherein the emitter area of ​​transistor QBN is "n" times (e.g., 8 or 10) the emitter area of ​​transistor QB1. The difference in emitter area results in different current densities in the corresponding PN junctions (e.g., emitter-base junctions) of transistors QB1 and QBN. These different current densities generate different voltages at the corresponding inputs of operational amplifier 910. The generated voltages have a negative temperature coefficient, while the difference between the generated voltages has a positive temperature coefficient. The output of operational amplifier 910 drives the gates of transistors QH1 and QHN at a voltage of approximately 1.25 volts (e.g., making the inputs of operational amplifier 910 at equal voltages), which is independent of temperature variations, power supply fluctuations, and process variations.

[0108] The output of operational amplifier 910 is also coupled to the gate of transistor QHS (e.g., a scaling transistor), causing a scaling current to be generated in response to the output voltage of operational amplifier 910. The drain of transistor QHS is coupled to the emitter of transistor QBS (e.g., a scaling transistor), allowing the scaling current to conduct through the emitter of transistor QBS. Scaling of the scaling transistors QHS and QBS (and the adjustable / trimmable resistors RN and RS) can be selectively achieved by injecting stress-dependent currents from current source 822 (Isense_x current) and current source 842 (Isense_y current) in response to longitudinal and lateral substrate stresses to properly balance the voltage Vref (e.g., the drain voltage of QHS). In one example, the Isense_x and Isense_y currents are injected into the Vref node in response to longitudinal and lateral substrate stresses, thereby reducing stress-induced fluctuations (e.g., fluctuations caused by coupling components other than the orientation stress sensor). In one example, the Vref node is the output reference node, where Isense_x is the first axis sense signal and Isense_y is the second axis sense signal, and (where the first and second axis sense signals are injected into the output reference node of the analog circuit).

[0109] In various examples, directional stress sensors coupled to precision components are arranged to compensate for stress by separating stress components that are longitudinally or laterally aligned with the substrate crystal axis, without requiring complex signal conditioning (e.g., signal conditioning performed solely by an analog AFE, by low-order and / or high-order digital processing of the compensation circuitry, or by a combination thereof). As described above, different AFE topologies can be used depending on the end-use application (e.g., which may require temperature compensation, built-in amplification, or both). The directional stress signal applied for stress compensation (e.g., a first-axis sensing signal and a second-axis sensing signal) can be a stress-related voltage signal or a stress-related current signal. As described herein, substrate stress can be compensated by stress compensation circuitry in the analog domain, digital domain, or a combination thereof. The analog / digital boundary between the domains can be selected for specific system applications, chip topologies, process technologies, and circuit design constraints.

[0110] The directional stress compensation described herein may include circuitry for analog-based compensation, digital-based compensation, or mixed-signal compensation. Analog circuitry, such as directional stress sensors, is arranged to generate currents and / or voltages proportional to stress vectors (e.g., longitudinal stress vector, lateral stress vector, or a combination of both) to indicate stress-sensitive quantities for compensating relevant parameters of the circuitry to be compensated. A digital control interface (e.g., from an end-user or via an application running in the DSP of the compensation circuitry) may include calibration modes for precisely selecting (e.g., under active digital control) the parameters of the sensor and sensor system components for tuning; resistor fine-tuning information for selecting amplifier gain, component bias, offset blocks (e.g., analog or analog / digital circuitry that can compensate for offset voltages or currents of circuit components such as operational amplifiers); and coefficients for digital correction and compensation (e.g., based on regressions of temperature effects, stress effects, and / or both temperature and pressure effects).

[0111] Figure 10 This is a top view of wafer 1000, which is an example wafer including precision devices arranged between mutually orthogonal sensing direction stress sensors.

[0112] The first axial stress sensor (e.g., for sensing the longitudinal resultant force of the stress vector) includes a series-coupled resistor pair XR TRAN and XR LONG . Figure 10 Resistor for XR TRAN and XR LONG It can be similar to Figure 2 Resistor for XR TRAN and XR LONG . Figure 10 Resistor for XR TRAN and XR LONGArranged near precision device 220, such that (e.g.) a portion of precision device 220 is located in XR TRAN Part of XR LONG Between a portion of them. Because the sensor is aligned along the axis of applied stress and measures the applied stress on both sides (e.g., proximal and distal) of the precision device (e.g., it improves the accuracy of the first axial stress sensor compared to a directional stress sensor located further away from and / or on one side of the precision device 220), the resistor is placed between XR TRAN and XR LONG Arranged around the precision device 220 (e.g., such that a portion of the precision device 220 is located in the XR) TRAN Part of XR LONG (between a portion of the data), which can improve the sensing of the resultant stress vector (e.g., longitudinal stress vector) acting on the precision device 220.

[0113] The second-axis stress sensor (e.g., for sensing the lateral or second-axis resultant force of the stress vector) includes a series-coupled resistor pair YR. TRAN and YR LONG Although oriented relative to the Y-axis, Figure 10 The resistor for YR TRAN and YR LONG It can be similar to Figure 2 Resistor for XR TRAN and XR LONG . Figure 10 The resistor for YR TRAN and YR LONG Arranged near precision device 220, such that (for example) a portion of precision device 220 is located in YR TRAN Part of YR LONG Between a portion of them. Because the sensor is aligned along the axis of applied stress and measures the applied stress on both sides (e.g., the proximal and distal sides) of the precision device (e.g., it improves the accuracy of the second axial stress sensor compared to a directional stress sensor that is farther from and / or located on one side of the precision device 220), the resistor is paired with YR. TRAN and YR LONG Arranged around the precision device 220 (e.g., such that a portion of the precision device 220 is located in YR) TRAN Part of YR LONG (between a portion of the part), which can improve the sensing of the resultant force of the stress vector (e.g., the transverse stress vector) acting on the precision device 220.

[0114] Figure 11This is a top view of wafer 1100, which is an example wafer including precision devices arranged between mutual longitudinal sensing direction stress sensors.

[0115] The first axial stress sensor (e.g., for sensing a first longitudinal resultant force of the stress vector) includes a series-coupled resistor pair X1. RTRAN and X2R LONG . Figure 11 The resistor for X1R TRAN and X1R LONG It can be similar to Figure 2 Resistor for XR TRAN and XR LONG . Figure 11 The resistor for X1R TRAN and X1R LONG Arranged near precision device 220, such that (for example) a portion of precision device 220 is located in X1R TRAN Part of the X1R LONG Between a portion. Because the sensor is aligned along the axis of applied stress and measures the applied stress on both sides (e.g., proximal and distal) of the precision device (e.g., it improves the accuracy of the first axial stress sensor compared to a directional stress sensor located further away from and / or on one side of the precision device 220), the resistor is paired with X1. RTRAN and X1R LONG Arranged around the precision device 220 (e.g., such that a portion of the precision device 220 is located in X1R) TRAN Part of the X1R LONG (between a portion) can improve the sensing of the resultant force of the stress vector (e.g., the longitudinal stress vector) acting on the precision device 220.

[0116] The second first-axis stress sensor (e.g., for sensing the second longitudinal or first-axis resultant force of the stress vector) includes a series-coupled resistor pair X2R. TRAN and X2R LONG . Figure 11 The resistor for X2R TRAN and X2R LONG It can be similar to Figure 2 The resistor for YR TRAN and YR LONG Although the longitudinal and transverse conductors are arranged inversely proportional to their resistance, this allows the longitudinal resultant force to be sensed in the additional sensing area. Figure 11 The resistor for X2R TRAN and X2R LONG Arranged near precision device 220, such that (for example) a portion of precision device 220 is located in X2R TRAN Part of X2RLONG Between a portion. Because the sensor is aligned along the axis of applied stress and measures the applied stress on all four sides of the precision device (e.g., combining the output signals of the first and second axial stress sensors improves the sensing accuracy relative to a single directional stress sensor or a single directional stress sensor located away from and / or on one side of the precision device 220), the resistor is paired with X2R. TRAN and X2R LONG Arranged around the precision device 220 (e.g., such that a portion of the precision device 220 is located at X2R) TRAN Part of X2R LONG This can improve the sensing of the resultant stress vector (e.g., longitudinal stress vector) acting on the precision device 220.

[0117] Figure 12 This is a top view of an example wafer 1200, showing an example structure including a reference resistor and a stress-sensitive resistor from a Wheatstone bridge. Quadrant 1201 includes a first x-axis stress sensor comprising a series-coupled resistor pair X1R. TRAN and X1R LONG A first x-axis stress sensor is arranged to sense a first longitudinal (e.g., first first axis) resultant force of a stress vector positioned relative to the precision device 1220. Quadrant 1201 also includes a second x-axis stress sensor comprising a series-coupled resistor pair X2R. TRAN and X2R LONG The second x-axis stress sensor is arranged to sense a second longitudinal resultant force (e.g., a second first-axis resultant force) of the stress vector positioned relative to the precision device 1220. Figure 12 The structure of quadrant 1201 can be similar to Figure 11 The structure.

[0118] Quadrant 1202 includes a first y-axis stress sensor, which includes a series-coupled resistor pair Y1R. TRAN and Y1R LONG A first y-axis stress sensor is arranged to sense a first lateral resultant force (e.g., a first second-axis resultant force) of the stress vector positioned relative to the precision device 1222. Quadrant 1202 also includes a second y-axis stress sensor comprising a series-coupled resistor pair Y2R. TRAN and Y2R LONG The second y-axis stress sensor is arranged to sense a second lateral resultant force (e.g., a second y-axis resultant force) of the stress vector positioned relative to the precision device 1222. Figure 12 The structure of quadrant 1202 can be similar to Figure 10 The structure, although the structure in quadrant 1202 is arranged to sense the longitudinal stress vector.

[0119] Precision device 1220 may include a first pair of adjustable resistors (such as resistors Rrefxa and Rrefxb of the X-axis stress sensor 440), and the first and second axial stress sensors may be resistors Rsense_xa and Rsense_xb of the X-axis stress sensor 440, respectively, such that components of the quadrant 1201 structure can be coupled to a Wheatstone bridge of the X-axis stress sensor 440. Since the two reference resistors used to generate the differential signal Vsense_x at each end are at least as described above regarding... Figure 11 The increased accuracy is due to the aforementioned reasons, and therefore (for example, when arranged as shown by the structure of quadrant 1201), the accuracy of the X-axis stress sensor 440 is increased.

[0120] Precision device 1222 may include a second pair of adjustable resistors (such as resistors Rrefya and Rrefyb for a second axial stress sensor (e.g., Y-axis stress sensor 450), and the third and fourth axial stress sensors may be resistors Rsense_ya and Rsense_yb for the second axial stress sensor (e.g., Y-axis stress sensor 450), respectively, such that components of the quadrant 1202 structure can be coupled to an example Wheatstone bridge for the Y-axis stress sensor 450. Since the two reference resistors used to generate the differential signal Vsense_y at each end are at least as described above regarding... Figure 11 The accuracy is increased due to the aforementioned reasons, and therefore the accuracy of the example Wheatstone bridge of the Y-axis stress sensor 450 is increased when arranged according to the structure of quadrant 1202.

[0121] Figure 13 An example region of a semiconductor substrate is shown, which includes an example precision component, an example first axial stress sensor, and an example second axial stress sensor. Region 1300 is an example region including regions 1310 and 1330, which together illustrate an example layout of the example precision component, the example first axial stress sensor, and the example second axial stress sensor.

[0122] Region 1310 includes the first axial stress sensor and precision component XR. REF The first axial stress sensor includes a series-coupled resistor pair for XR. TRAN and XR LONG The first axial stress sensor is arranged to sense relative to the precision component XR. REF The longitudinal resultant force of the positioned stress vector (e.g., the resultant force along the first axis).

[0123] Region 1330 includes the second axial stress sensor and precision component YR. REFThe second axial stress sensor includes a series-coupled resistor pair YR. TRAN and YR LONG The second axial stress sensor is arranged to sense stress relative to the precision component YR. REF The resultant force of the positioned stress vector in the transverse direction (e.g., the resultant force along the second axis).

[0124] Precision Components XR REF A precision component XR is formed between a portion of a first axial stress sensor formed in region 1310 of region 1300 and a portion of a second axial stress sensor formed in region 1330 of region 1300. REF More accurately determining the instantaneous magnitude of the stress vector affects the XR of precision components. REF The performance parameters (compared to the less precisely determined instantaneous magnitude of the stress vector applied to a precision component that does not form between the two).

[0125] Figure 14 This is a layout diagram showing an example Wheatstone bridge layout including two example X-axis sensors, each with a corresponding example accuracy component. The example Wheatstone bridge can be an example layout of the X-axis direction stress sensor 440 described above.

[0126] An example Wheatstone bridge is formed on region 1400 of a semiconductor substrate. Region 1400 is an example region including regions 1410 and 1430, which together illustrate an example layout of an X-axis stress sensor 440.

[0127] Region 1410 includes the first axial stress sensor and precision component X1R. REF The first axial stress sensor includes a series-coupled resistor pair X1R. TRAN and X1R LONG A first axial stress sensor is arranged to sense relative to the precision component X1R. REF The longitudinal resultant force of the positioned stress vector (e.g., the resultant force along the first axis).

[0128] Region 1420 includes a second first-axis stress sensor and precision component X2R. REF The second first-axis stress sensor includes a series-coupled resistor pair X2R. TRAN and X2R LONG The second first-axis stress sensor is arranged to sense relative to the precision component X2R. REF The longitudinal resultant force of the positioned stress vector (e.g., the resultant force along the first axis).

[0129] Precision Components X1R REF and X2R REFA portion of the first axial stress sensor formed in region 1410 of region 1400 and a portion of the second axial stress sensor formed in region 1420 of region 1400 are formed therebetween. A precision component X1R is formed therebetween. REF and X2R REF More accurately determine the factors affecting precision components X1R REF and X2R REF The instantaneous magnitude of the stress vector of the performance parameters (compared to the less precisely determined instantaneous magnitude of the stress vector applied to the precision components not formed therein). The accuracy of the Wheatstone bridge arranged in zone 1400 includes better matching of process defects, reduced noise, the increased component due to the increased output voltage generated between the corresponding intermediate nodes of each of the two branches of the Wheatstone bridge (e.g., doubled compared to one branch of the Wheatstone bridge), and a more balanced effect of local stress applied to each branch of the Wheatstone bridge. Therefore, the effects of stress are differentially reduced (if not completely eliminated) by the differential output signal.

[0130] Figure 15 This is a layout diagram illustrating an example stress gradient of an example integrated circuit formed on a semiconductor substrate. Integrated circuit 1500 is an example integrated circuit including first axial stress sensors X1-X8, second axial stress sensors Y1-Y8, precision components 1510 and 1520, and a processor (e.g., at least one microcontroller 1530) coupled to the stress sensors and precision components (e.g., enabling the processor to receive indications of directional stress received by each stress sensor, and enabling the processor to generate at least one compensation signal in response to the received stress indications, and to apply the compensation signals to the respective precision components). As described below, the example stress gradient propagates through a first location, a second location, and a third location of the piezoelectric material, and one or more processors are arranged to determine a corresponding value of the stress gradient at each location in response to a corresponding indication of at least one stress vector received from the respective stress sensors.

[0131] Integrated circuit 1500 includes a stress gradient 1502, which can be formed in response to packaging operations (which may include process defects that can lead to unevenly distributed mounting stresses) and / or thermal cycling (which may include heat generated by electrical components and / or differences in thermal expansion of materials applied at different stages of the manufacturing / packaging process). The stress applied by the applied force can “decrease” with the square of the distance between the point where the applied force is applied. Furthermore, various stresses can be applied from different locations and different directions, and can be dynamically changed during the operation of the integrated circuit (and can also be changed during the device’s lifetime for similar operating conditions).

[0132] In one example, stress gradient 1502 may result in differences in thermal expansion between: mounting integrated circuit 1500 on IC package (or other chip carrier) at a first temperature, a change in the first temperature, IC package (not shown), integrated circuit 1500 and / or adhesives / sealants disposed therebetween.

[0133] The processor is arranged to read indications from each stress sensor, wherein the position (e.g., in Cartesian coordinates) and orientation of each sensor are predetermined (e.g., known to the processor). In operation: the processor can interpolate stress with a first orientation for each point (e.g., position and / or quantum) across the surface of integrated circuit 1500, the processor can interpolate stress with a second orientation for each point across the surface of integrated circuit 1500, and the processor can interpolate stress with a third orientation for each point across the surface of integrated circuit 1500. Accordingly, stress gradient 1502 may include one, two, or three orientations of the stress vector (which may include a shear vector that is non-orthogonal to one or more other orientations of the stress vector), and the processor can interpolate stress with respect to each measurement dimension (including the Z dimension, not shown for clarity). Figure 15 (As shown in the figure) Interpolation intermediate stress.

[0134] The processor can interpolate intermediate stresses in response to received stress indications (for a given orientation) using linear interpolation (for faster processing), logarithmic interpolation, or other interpolation techniques (e.g., cubic spline curves). The processor can determine the stress gradient at the start of operation, upon reset, periodically, or continuously (e.g., in a raster scan manner).

[0135] The stresses affecting the performance parameters of precision components can be more closely determined (e.g., during design) by arranging the precision component (e.g., precision component 1510) adjacent to specific stress sensors (e.g., stress sensors X5-X8 and Y5-Y8). The stresses affecting the performance parameters of each different precision component can be determined in response to a given number of stress sensors closest to a given precision component: for example, the stresses affecting the performance parameters of precision component 1520 can be determined in response to interpolated stress indications received from stress sensors X1, X5, X6, and X2, and Y1, Y5, Y6, and Y2. Therefore, the precision of the selected precision component can be compensated for during operation in response to the relative importance of the criticality of each respective precision component.

[0136] In one example, integrated circuit 1500 includes a substrate comprising a piezoelectric material having a crystal axis (e.g., axis X) and a first piezoresistive coefficient (e.g., π) oriented relative to the crystal axis. LONG ) and a second piezoresistive coefficient (e.g., π) having a second axial orientation different from the first orientation.TRAN or π VERT ).

[0137] In this example, the integrated circuit 1500 also includes a precision component 1510 formed on a substrate at a first location, and includes performance parameters affected by the stress vector applied in the piezoelectric material.

[0138] In this example, the integrated circuit 1500 also includes a first stress sensor formed on a substrate in a second location, the first stress sensor being coupled to a precision component.

[0139] In this example, the integrated circuit 1500 also includes a second stress sensor formed on a substrate in a third location, the second stress sensor being coupled to a precision component.

[0140] In this example, the integrated circuit 1500 also includes a processor (e.g., at least one microcontroller 1530) coupled to the precision component 1510, the first stress sensor, and the second stress sensor, and is arranged to generate a compensation amount in response to the output of the first stress sensor and the output of the second stress sensor, and in response to a first position, a second position, and a third position, wherein the compensation amount is applied to the precision component such that the output signal of the precision component 1510 affected by performance parameters is compensated in response to the compensation amount.

[0141] In another example, the processor is arranged to generate a compensation amount in response to stress gradients at first, second, and third locations of a piezoelectric material extending through a substrate, wherein at least one value of the stress gradient at the first location is determined in response to an indication of at least one stress vector received from a first stress sensor and in response to an indication of at least one stress vector received from a second stress sensor.

[0142] Example methods of certain techniques described herein include: arranging precision components (e.g., those included by precision device 220 or a calibrable, adjustable resistor to limit or otherwise control current) on a piezoelectric material, wherein the piezoelectric material (e.g., 200) has a crystal axis (e.g., axial X) and a first piezoresistive coefficient (e.g., π) oriented relative to (e.g., longitudinally) the crystal axis. LONG ), and a second piezoresistive coefficient (e.g., π) having a second axis orientation different from (e.g., transverse to) the first orientation. TRAN A precision component (e.g., 1220) is arranged on a piezoelectric material, wherein the precision component includes at least one performance parameter affected by stress applied to the piezoelectric material; a first axial stress sensor (e.g., 210, Rsense_xa) is arranged on the piezoelectric material and electrically coupled to the precision component, wherein the first axial stress sensor includes a second axial stress sensing resistor (e.g., XR).TRAN or XR VERT A first axial stress sensing resistor (e.g., XR) coupled in series LONG The first axial stress sensing resistor includes a first axial conductor arranged along (e.g., longitudinally to) the crystal axis, and the second axial stress sensing resistor includes a second axial conductor arranged transversely to the crystal axis, wherein the ratio of the resistance of the first stress sensing resistor to the resistance of the second stress sensing resistor is proportional to the ratio of the first piezoresistive coefficient to the second piezoresistive coefficient; a first axial sensing signal is generated by the first axial stress sensor in response to a first axial resultant force of stress applied in the piezoelectric material; and an analog compensation signal is generated by the compensation circuit (e.g., compensation circuit 240 or signal conditioner 420) in response to the analog signal received from the compensation circuit and the first axial sensing signal.

[0143] Example methods of some of the techniques described herein may also include calibrating precision components (e.g., adjustable resistors) to limit the current of the first stress sensor in order to reduce the impact of the applied stress on at least one performance parameter of the analog circuit to be compensated.

[0144] Within the scope of the claims, modifications may be made to the described embodiments, and other embodiments are also possible.

Claims

1. A circuit comprising: A piezoelectric material having a crystal axis, a first piezoresistive coefficient having a first axial orientation relative to the crystal axis, and a second piezoresistive coefficient having a second axial orientation different from the first axial orientation; A simulation front-end having a simulation front-end output, wherein the simulation front-end is arranged to generate a simulation compensation signal at the simulation front-end output in response to an electrical signal to be compensated and a first axial stress sensing signal, and wherein the simulation front-end includes: A precision component, arranged on the piezoelectric material and configured to generate the electrical signal to be compensated, which is affected by stress applied in the piezoelectric material; and A first axial stress sensor, disposed on the piezoelectric material and coupled to the precision component, wherein the first axial stress sensor includes a first axial stress sensing resistor coupled in series with a second axial stress sensing resistor, the first axial stress sensing resistor including a first axial conductor oriented along the first axis, and the second axial stress sensing resistor including a second axial conductor oriented along the second axis, wherein the ratio of the resistance of the first axial stress sensing resistor to the resistance of the second axial stress sensing resistor is proportional to the ratio of the first piezoresistive coefficient to the second piezoresistive coefficient, wherein the first axial stress sensor is arranged to generate a first axial sensing signal in response to a first axial resultant force of stress applied in the piezoelectric material; and A compensation circuit includes a first input coupled to the output of the analog front end, a second input coupled to the output of the analog circuit to be compensated, and is arranged to generate a compensation output signal at the output of the analog front end, wherein the compensation output signal is generated by the compensation circuit in response to the analog compensation signal and the output signal of the analog circuit to be compensated.

2. The circuit of claim 1, wherein the precision component includes a calibrated resistor.

3. The circuit of claim 1, wherein the analog front end further comprises a second axial stress sensor disposed on the piezoelectric material, the second axial stress sensor being arranged to generate a second axial sensing signal in response to a second axial resultant force of stress applied in the piezoelectric material.

4. The circuit of claim 3, wherein the analog front end further comprises a third-axis stress sensor disposed on the piezoelectric material, the third-axis stress sensor being arranged to generate a third-axis sensing signal in response to a third-axis resultant force of the stress applied in the piezoelectric material.

5. The circuit of claim 1, wherein the first axial stress sensor includes a first terminal coupled to a first power rail and a second terminal coupled to the first terminal of the precision component, wherein the second terminal of the precision component is coupled to a second power rail.

6. The circuit of claim 5, wherein the first axial stress sensor is a first first axial stress sensor, the precision component is a first precision component, the circuit further comprising a second precision component and a second first axial stress sensor, wherein the second first axial stress sensor includes a first terminal coupled to the second power rail and a second terminal coupled to the first terminal of the second precision component, and wherein the second precision component further includes a second terminal coupled to the first power rail.

7. The circuit of claim 6, wherein the first first axial stress sensor, the second first axial stress sensor, the first precision component and the second precision component are arranged in a Wheatstone bridge, wherein the first axial sensing signal is a first axial sensing signal differential signal having a first end generated at the second terminal of the first axial stress sensor and a second end generated at the first terminal of the second first axial stress sensor.

8. The circuit according to claim 7, comprising an amplifier and a feedback resistor, for converting the differential signal of the first axis sensing signal into a single-ended signal of the first axis sensing signal.

9. The circuit of claim 5, wherein a portion of the precision component is located between a portion of the first axial stress sensing resistor connected in series with the second axial stress sensing resistor.

10. The circuit of claim 5, wherein the compensation circuit includes a DSP.

11. The circuit of claim 1, wherein the compensation circuit includes a second output coupled to the analog circuit to be compensated, wherein the compensation circuit is arranged to generate a compensation feedback signal at the second output in response to the analog compensation signal.

12. The circuit of claim 1, wherein the analog front end includes at least one operational amplifier arranged to control a current coupled to generate the analog compensation signal in response to the precision component.

13. The circuit of claim 12, wherein the at least one operational amplifier is arranged to generate an amplified analog compensation signal in response to the ratio of the value of the first axial stress sensor to the value of the precision component.

14. The circuit of claim 1, wherein the analog front end includes at least one current source arranged to generate a source current, wherein the analog compensation signal is generated in response to the source current and in response to the difference between the precision component and the first shaft stress sensor.

15. The circuit of claim 1, wherein the analog front end further comprises a second axial stress sensor arranged to generate a second axial sensing signal in response to a second axial resultant force of stress applied in the piezoelectric material, and wherein the compensation circuit is arranged to generate a combined analog compensation signal in response to the first axial sensing signal and the second axial sensing signal, and wherein the first axial sensing signal and the second axial sensing signal are current signals.

16. The circuit of claim 15, comprising an analog circuit having an output reference node, wherein the first axis sensing signal and the second axis sensing signal are injected into the output reference node of the analog circuit.

17. A system comprising: A piezoelectric material having a crystal axis, a first piezoresistive coefficient having a first axial orientation relative to the crystal axis, and a second piezoresistive coefficient having a second axial orientation different from the first axial orientation; A precision component formed in a first location on the piezoelectric material, wherein the precision component includes performance parameters affected by stress applied in the piezoelectric material; A first stress sensor is formed in a second location on the piezoelectric material and is coupled to the precision component. A second stress sensor is formed in a third location on the piezoelectric material and is coupled to the precision component. as well as A processor coupled to the precision component, the first stress sensor, and the second stress sensor, and arranged to generate a compensation amount in response to the outputs of the first stress sensor and the second stress sensor, and in response to the first position, the second position, and the third position, wherein the compensation amount is applied to the precision component to compensate for the output signal of the precision component affected by the performance parameters.

18. The system of claim 17, wherein the processor is arranged to generate the compensation amount in response to a stress gradient propagating through the first, second, and third locations of the piezoelectric material, wherein at least one value of the stress gradient at the first location is determined in response to a first indication of at least one stress vector received from the first stress sensor and a second indication of at least one stress vector received from the second stress sensor.

19. A method comprising: Precision components are arranged on a piezoelectric material, wherein the piezoelectric material has a crystal axis, a first piezoresistive coefficient having a first axis orientation relative to the crystal axis and a second piezoresistive coefficient transverse to the crystal axis, wherein the precision components include performance parameters affected by stress applied in the piezoelectric material; A first axial stress sensor is disposed on the piezoelectric material and electrically coupled to the precision component, wherein the first axial stress sensor includes a first axial stress sensing resistor coupled in series with a second axial stress sensing resistor, the first axial stress sensing resistor including a first axial conductor arranged along the crystal axis, and the second axial stress sensing resistor including a second axial conductor arranged transversely to the crystal axis, wherein the ratio of the resistance of the first axial stress sensing resistor to the resistance of the second axial stress sensing resistor is proportional to the ratio of the first piezoresistive coefficient to the second piezoresistive coefficient; A first axial sensing signal is generated by the first axial stress sensor in response to a first axial resultant force of stress applied to the piezoelectric material; as well as In response to the analog signal received from the circuit to be compensated and the first axis sensing signal, an analog compensation signal is generated by the compensation circuit.

20. The method of claim 19, further comprising calibrating the precision component to limit the current of the first axis stress sensor to reduce the effect of stress applied in the piezoelectric material on the performance parameter of the circuit to be compensated.

Images