Temperature sensing structure and radio frequency circuit

Abstract

A temperature sensing structure is used to sense a temperature of an object. The temperature sensing structure includes a temperature sensing element and a thermal conduction component. The thermal conduction component is coupled between the temperature sensing element and the object to conduct heat. The thermal conduction component includes a first metal body, a second metal body, and a metal-insulator-metal structure. The first metal body is coupled to the temperature sensing element, the second metal body is coupled to the object, and the metal-insulator-metal structure is connected between the first metal body and the second metal body.

Description

Technical Field

[0001] This invention relates to a semiconductor element, and more particularly to a temperature sensing structure and radio frequency circuit. Background Technology

[0002] In techniques that use an external controller to adjust a radio frequency (RF) power amplifier (PA), a temperature sensor (TS) is required. When the temperature sensor is fabricated using gallium arsenide (GaAs) technology, because GaAs has lower thermal conductivity and a slower thermal conduction speed than silicon (Si), simply placing the temperature sensor next to the power amplifier will cause a time lag in temperature sensing between the power amplifier and the temperature sensor due to the thermal conductivity of GaAs. This will result in a delay in the external controller receiving the temperature sensing results, thus preventing the external controller from adjusting the power amplifier in a timely manner. Summary of the Invention

[0003] This invention provides a temperature sensing structure that can significantly reduce the time it takes for the heat energy of the object under test to be conducted to the temperature sensing element and improve the overall heat transfer.

[0004] The present invention also provides a radio frequency circuit that can be used to improve the performance of a radio frequency power amplifier.

[0005] In one embodiment of the present invention, a temperature sensing structure is used to sense the temperature of a test object. The temperature sensing structure includes a temperature sensing element and a heat conduction component. The heat conduction component is coupled between the temperature sensing element and the test object to conduct heat. The heat conduction component includes a first metal body, a second metal body, and a metal-insulator-metal structure. The first metal body is coupled to the temperature sensing element, the second metal body is coupled to the test object, and the metal-insulator-metal structure is connected between the first metal body and the second metal body.

[0006] In another embodiment of the present invention, the radio frequency circuit includes an amplifier element and a temperature sensing structure, wherein the temperature sensing structure is used to sense the temperature of the amplifier element. The temperature sensing structure includes a temperature sensing element and a heat conduction component. The heat conduction component is coupled between the temperature sensing element and the amplifier element for heat conduction. The heat conduction component includes a first metal body, a second metal body, and a metal-insulator-metal structure. The first metal body is coupled to the temperature sensing element, the second metal body is coupled to the amplifier element, and the metal-insulator-metal structure is connected between the first metal body and the second metal body.

[0007] To make the above features of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0008] Figure 1 This is a cross-sectional schematic diagram of a temperature sensing structure according to the first embodiment of the present invention.

[0009] Figure 2 This is a cross-sectional schematic diagram of a temperature sensing structure according to a second embodiment of the present invention.

[0010] Figure 3 This is a cross-sectional schematic diagram of a temperature sensing structure according to a third embodiment of the present invention.

[0011] Figure 4 yes Figure 3 Top view of a portion of the temperature sensing structure.

[0012] Figure 5 This is a radio frequency circuit diagram according to the fourth embodiment of the present invention.

[0013] Figure 6 This is a radio frequency circuit diagram according to the fifth embodiment of the present invention.

[0014] Symbol explanation:

[0015] 100, 100', 100”, 100”': Temperature sensing structure

[0016] 101: Base

[0017] 102: Test Item

[0018] 104, 200, 302: First metallic body

[0019] 106, 202, 304: Second metal body

[0020] 108, 204, 306, MIM: Metal-Insulator-Metal Structure

[0021] 110, 206: Third metal body

[0022] 112: Insulator

[0023] 114, 208: Fourth Metallic Body

[0024] 116: Through hole

[0025] 118: The Fifth Metal

[0026] 120, 210, 212, 214, 300, 308: Dielectric layer

[0027] B1, B2: Base

[0028] C1, C2: Collectors

[0029] cs1: First side view

[0030] cs2: Second side

[0031] d1, d2, d3, d5, d6: Shortest distance

[0032] d4: Distance

[0033] E1, E2: Emitters

[0034] GC: Geometric Center

[0035] PA: Amplifier Component

[0036] s1: First surface

[0037] s2: Second surface

[0038] s3: Third surface

[0039] s4: Fourth surface

[0040] t: thickness

[0041] TC, TC', TC”, TC”': Heat conduction components

[0042] TS: Temperature sensing element

[0043] v1, v2: Interlayer window

[0044] V CC V DD Power supply voltage

[0045] 500: DC signal

[0046] 502: Heat Flow

[0047] 600: Capacitor Detailed Implementation

[0048] Figure 1 This is a cross-sectional schematic diagram of a temperature sensing structure according to a first embodiment of the present invention. Figure 1 In the first embodiment, the temperature sensing structure 100 is used to sense the temperature of a test object 102. The temperature sensing structure 100 is generally formed on a substrate 101, and the test object 102 and the temperature sensing structure 100 can be formed on the same substrate 101, but the present invention is not limited thereto.

[0049] Please continue to refer to Figure 1The temperature sensing structure 100 includes a temperature sensing element TS and a heat conduction component TC. The temperature sensing element TS can be, for example, a bipolar junction transistor (BJT), a diode, a resistor, or other suitable components for temperature detection. For instance, if a BJT is used as the temperature sensing element TS, the temperature of the object under test 102 can be obtained through the change in the base-emitter bias voltage. Conversely, if a diode is used as the temperature sensing element TS, the temperature of the object under test 102 can be obtained through the change in the forward bias voltage of the diode. Furthermore, if a resistor is used as the temperature sensing element TS, the temperature of the object under test 102 can be obtained through the change in its resistance value.

[0050] A heat conduction component TC is coupled between a temperature sensing element TS and the object to be measured 102 for heat conduction. The heat conduction component TC includes a first metal body 104, a second metal body 106, and a metal-insulator-metal structure 108. The first metal body 104 is coupled to the temperature sensing element TS, the second metal body 106 is coupled to the object to be measured 102, and the metal-insulator-metal structure 108 is connected between the first metal body 104 and the second metal body 106. In a first embodiment, the metal-insulator-metal structure 108 includes a third metal body 110, an insulator 112, and a fourth metal body 114 stacked along a thickness direction, with the insulator 112 connected between the third metal body 110 and the fourth metal body 114. The third metal body 110 is connected to the first metal body 104, and the fourth metal body 114 is connected to the second metal body 106, so that the temperature of the object to be measured 102 is conducted to the temperature sensing element TS via the heat conduction component TC containing the above structures. Compared to temperature sensing devices without a metal-insulator-metal structure 108, the heat conduction time of the heat conduction component TC with a metal-insulator-metal structure 108 can be reduced by about 1000 times, and the heat transfer can be increased by about 1000 times.

[0051] exist Figure 1 In this embodiment, the shortest distance d1 between the second metal body 106 and the first metal body 104 in the thickness direction is greater than the thickness t of the insulator 112. In some embodiments, the ratio (d1 / t) of the shortest distance d1 between the second metal body 106 and the first metal body 104 to the thickness t of the insulator 112 is greater than or equal to 5 and less than or equal to 25. If the ratio (d1 / t) is less than 5, the path of the heat conduction component TC is too long, which is not conducive to heat conduction; if the ratio (d1 / t) is greater than 25, it will cause a short circuit. Figure 1The fourth metal body 114 and the second metal body 106 are shown as two separate structures, but the invention is not limited thereto. The fourth metal body 114 and the second metal body 106 can also be formed together above the first metal body 104 and the third metal body 110 through a process. Because the thickness t of the insulator 112 is smaller than the shortest distance d1 between the second metal body 106 and the first metal body 104, the fourth metal body 114 is slightly thinner than the second metal body 106 in the thickness direction. Furthermore, in order to enable the heat conduction component TC to more effectively conduct the temperature of the test object 102, the heat conduction component TC may also include a through-hole 116 and a fifth metal body 118, wherein the second metal body 106 is coupled to the test object 102 through the through-hole 116 and the fifth metal body 118. In some embodiments, the fifth metal body 118, the first metal body 104, and the third metal body 110 can be fabricated using the same process. For example, the fifth metal body 118, the first metal body 104, and the third metal body 110 are all the first metal layer (also referred to as M1) in a semiconductor device, and the circuitry in different locations is defined by a photomask process, but this is not limited to this. In other embodiments, the formation steps of the fifth metal body 118 may differ from the formation steps of the first metal body 104 and the third metal body 110. Furthermore, in the figure, a single dielectric layer 120 represents the film layer covering the temperature sensing element TS and the heat conduction component TC, but it should be understood that this single dielectric layer 120 may be composed of several layers of dielectric material.

[0052] In one embodiment, the thickness t of the insulator 112 is less than 1 μm, for example, less than 0.5 μm, to facilitate heat conduction; on the other hand, the thickness t of the insulator 112 is only sufficient to electrically block the DC operation of the test object 102. In embodiments considering radio frequency applications, the equivalent capacitance of the metal-insulator-metal structure 108 can be greater than or equal to 50 fF and less than or equal to 300 fF; or, the contact area between the insulator 112 and the third metal body 110 is greater than or equal to 86 μm. 2 And less than or equal to 530μm 2 Compared to temperature sensing devices without the metal-insulator-metal structure 108, the heat-conducting component TC with the metal-insulator-metal structure 108 only changes the operating current of the device under test (DUT) 102 by 0.5%, and the operating power of the DUT 102 changes by less than 0.3% for both high-power and low-power signals, indicating that the metal-insulator-metal structure 108 has a very small impact on the DUT 102. However, the invention is not limited thereto; in embodiments that do not consider radio frequency applications, the equivalent capacitance of the metal-insulator-metal structure 108 can be increased or decreased as needed; or, the contact area between the insulator 112 and the third metal body 110 can be increased or decreased as needed.

[0053] Please refer to this again. Figure 1The insulator 112 does not overlap with the temperature sensing element TS. In other words, in the cross-sectional view, the shortest distance d3 between the insulator 112 and the temperature sensing element TS in a length direction is at least greater than 0. In some embodiments, the shortest distance d2 between the temperature sensing element TS and the object under test 102 in a length direction may be less than the shortest distance d3 between the temperature sensing element TS and the insulator 112 in a length direction, that is, the temperature sensing element TS is positioned closer to the object under test 102 in the length direction and is separated from the metal-insulator-metal structure 108 by a considerable distance. The length direction is, for example, parallel to the surface of the substrate 101 (e.g., closer to the upper surface of the temperature sensing element TS or the object under test 102, or farther from the lower surface of the temperature sensing element TS or the object under test 102), and perpendicular to the thickness direction. The cross-sectional view is, for example, located in a reference plane formed by the thickness direction and the length direction. The proximity of the temperature sensing element TS to the object under test 102 not only further reduces the element area but also increases the sensing speed by reducing the thermal conduction distance. On the other hand, Figure 1 The detailed structure of the temperature sensing element TS is not shown, but the surface of the temperature sensing element TS may not be a flat profile. If the metal-insulator-metal structure 108 is directly placed on the surface of the temperature sensing element TS, the thinner insulator 112 may break in uneven or sloping areas. The following discussion will focus on the specific application of the metal-insulator-metal structure TS. Figure 2 The described paragraphs will further explain this. Therefore, in order to enable the metal-insulator-metal structure 108 to be formed on a flatter surface farther away from the temperature sensing element TS, the shortest distance d3 between the metal-insulator-metal structure 108 and the temperature sensing element TS in the longitudinal direction is larger than the shortest distance d2 between the temperature sensing element TS and the object under test 102 in the longitudinal direction, which can also improve the reliability of the metal-insulator-metal structure 108.

[0054] Figure 2 This is a cross-sectional schematic diagram of a temperature sensing structure according to a second embodiment of the present invention, wherein a temperature sensing structure is used with... Figure 1 The same component symbols are used to represent the same or similar parts and components, and the relevant information about the same or similar parts and components can also be found by referring to... Figure 1 The content will not be repeated here.

[0055] exist Figure 2In this embodiment, the temperature sensing structure 100' includes a temperature sensing element TS and a heat conduction component TC'. In some embodiments, the temperature sensing element TS is made of gallium arsenide (GaAs), such as a gallium arsenide-containing bipolar junction transistor, which may include a collector C1, a base B1, and an emitter E1, with the emitter E1 located on the base B1 and the base B1 located on the collector C1. The heat conduction component TC' is coupled between the emitter E1 of the temperature sensing element TS and the object to be measured 102 for heat conduction. The heat conduction component TC' includes a first metal body 200, a second metal body 202, and a metal-insulator-metal structure 204, wherein the metal-insulator-metal structure 204 includes a third metal body 206, an insulator 112, and a fourth metal body 208. The first metal body 200 is conformally disposed on the temperature sensing element TS and can be coupled to the emitter E1 through a dielectric window v1 formed on the dielectric layer 210. In some embodiments, the fifth metal body 118 may also be coupled to the test object 102 via another dielectric window v2 formed in the dielectric layer 210, the via 116 and the fourth metal body 208 may be formed in the dielectric layer 212, and the second metal body 202 is formed in the dielectric layer 214 above the dielectric layer 212. However, the present invention is not limited thereto.

[0056] Please continue to refer to Figure 2 The first metal body 200 includes a first surface s1 and a second surface s2 opposite to each other, with the first surface s1 being away from the temperature sensing element TS. The third metal body 206 includes a third surface s3 and a fourth surface s4 opposite to each other, with the third surface s3 connecting to the insulator 112. Since the surface profile of the temperature sensing element TS is not a complete plane, the first surface s1, which is conformally formed on its surface, is less flat. In contrast, the area where the third metal body 206 is deposited is flatter, so the flatness of the third surface s3 of the third metal body 206 is greater than that of the first surface s1, ensuring that the metal-insulator-metal structure 204 does not break, thereby improving the structural stability of the temperature sensing structure 100' of the present invention. In the second embodiment, although the shape and size of the second metal body 202 and the fourth metal body 208 in the temperature sensing structure 100' are different from those in the first embodiment, they still meet the condition that the shortest distance d1 between the second metal body 202 and the first metal body 200 in the thickness direction is greater than the thickness t of the insulator 112. Furthermore, the range of the ratio of the shortest distance d1 to the thickness t (d1 / t) and other undescribed positional relationships, such as the shortest distance between the temperature sensing element TS and the object under test 102, the shortest distance between the temperature sensing element TS and the insulator 112, the range of the equivalent capacitance value of the metal-insulator-metal structure 204, or the contact area between the insulator 112 and the third metal body 206, can all follow the settings of the first embodiment or be adjusted to be larger or smaller as needed.

[0057] Figure 3 This is a cross-sectional schematic diagram of a temperature sensing structure according to a third embodiment of the present invention, wherein the structure is used with... Figure 1 The same component symbols are used to represent the same or similar parts and components, and the relevant information about the same or similar parts and components can also be found by referring to... Figure 1 The content will not be repeated here. Figure 4 yes Figure 3 A top view of a portion of the temperature sensing structure, with some components omitted for clarity.

[0058] Please refer to Figure 3 and Figure 4 The temperature sensing structure 100 of this embodiment includes a temperature sensing element TS and a heat conduction component TC. The temperature sensing element TS is a first bipolar junction transistor, and the object under test 102 is a second bipolar junction transistor. The temperature sensing element TS includes at least a collector C1 and a base B1 stacked along the thickness direction, and an emitter E1 is disposed on the base B1. The aforementioned collector C1 has a first side cs1 close to the object under test 102 and a second side cs2 away from the object under test 102. The object under test 102 includes at least a collector C2, a base B2, and an emitter E2, and the emitter E2 is located on the base B2, and the base B2 is located on the collector C2. The heat conduction component TC” is coupled between the emitter E1 of the temperature sensing element TS and the collector C2 of the object under test 102. In the length direction perpendicular to the thickness direction, the shortest distance d5 between the first side cs1 of the collector C1 and the geometric center GC of the base B1 is less than the shortest distance d6 between the second side cs2 of the collector C1 and the geometric center GC of the base B1. That is, the temperature sensing element TS in the temperature sensing structure 100” of the third embodiment is structurally an asymmetrical bipolar junction transistor. Compared with a general symmetrical bipolar junction transistor, the third embodiment of this case can reduce the distance d4 (in the length direction) between the emitter E1 of the temperature sensing element TS and the collector C2 of the object under test 102 by using an asymmetrical temperature sensing element TS, so as to shorten the heat conduction distance and further reduce the element area. The aforementioned distance d4 between the emitter E1 and the collector C2 is, for example, less than 12 μm, but is not limited to this.

[0059] Please continue to refer to Figure 3The heat-conducting component "TC" can be formed on the dielectric layer 300, and is connected to the emitter E1 through a dielectric window v1 in the dielectric layer 300 and to the collector C2 through a dielectric window v2 in the dielectric layer 300. The heat-conducting component "TC" includes at least a first metal body 302, a second metal body 304, and a metal-insulator-metal structure 306. The metal-insulator-metal structure 306 is similar to the structure in the above embodiments, including a third metal body 110, an insulator 112, and a fourth metal body 114. In some embodiments, the first metal body 302 and the third metal body 110 can be formed together on the dielectric layer 300 by a process, while the second metal body 304 can be formed on the dielectric layer 308 covering the first metal body 302 and the third metal body 110. As for the insulator 112 of the metal-insulator-metal structure 306, it can be formed within the dielectric layer 308, and the fourth metal body 114 is formed above the insulator 112.

[0060] Figure 5 and Figure 6 These are radio frequency circuit diagrams according to the fourth and fifth embodiments of the present invention, respectively.

[0061] exist Figure 5 In the circuit, the radio frequency circuit includes an amplifier element PA and a temperature sensing structure, such as the temperature sensing structure 100" in the third embodiment. The temperature sensing structure 100" includes a temperature sensing element and a heat conduction component. The temperature sensing element TS is, for example, the temperature sensing element TS in the first to third embodiments described above, and the temperature sensing element TS can sense the temperature of the amplifier element PA. The temperature sensing element TS is connected to the power supply voltage V. DD Amplifier component PA is connected to the power supply voltage V. CC The aforementioned heat conduction component is, for example, the heat conduction component TC” in the third embodiment, wherein the metal-insulator-metal structure MIM can prevent the DC signal 500 from being coupled to the temperature sensing element TS, but allows most of the heat flow 502 to reach the temperature sensing element TS via the heat conduction component TC”.

[0062] exist Figure 6 In the radio frequency circuit, there is an amplifier element PA and a temperature sensing structure 100”'. The temperature sensing structure 100”' includes a temperature sensing element TS and a heat conduction component TC”'. The temperature sensing element TS is, for example, the temperature sensing element TS in the first to third embodiments described above. Figure 6 The heat conduction component TC”' with Figure 5 The difference between the heat conduction components "TC" and "TC" lies in the fact that the heat conduction components are... Figure 5The metal-insulator-metal structure (MIM) is implemented as a capacitor 600 to prevent the DC signal 500 from being coupled to the temperature sensing element TS, but allows most of the heat flow 502 to reach the temperature sensing element TS via the heat conduction component TC”'.

[0063] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A temperature sensing structure for sensing the temperature of an object to be measured, characterized in that, The temperature sensing structure includes: A temperature sensing element; and A heat conduction component is coupled between the temperature sensing element and the object to be measured for heat conduction, the heat conduction component comprising: A first metal body is coupled to the temperature sensing element; A second metal body, coupled to the test object; and A metal-insulator-metal structure is connected between the first metal body and the second metal body.

2. The temperature sensing structure according to claim 1, characterized in that, The metal-insulator-metal structure includes a third metal body, an insulator, and a fourth metal body, wherein the insulator is connected between the third metal body and the fourth metal body.

3. The temperature sensing structure according to claim 2, characterized in that, The third metal body is connected to the first metal body, and the fourth metal body is connected to the second metal body.

4. The temperature sensing structure according to claim 3, characterized in that, In a reference plane formed by a thickness direction and a length direction, the insulator and the temperature sensing element do not overlap.

5. The temperature sensing structure according to claim 4, characterized in that, In the thickness direction, a shortest distance between the second metal body and the first metal body is greater than the thickness of the insulator.

6. The temperature sensing structure according to claim 5, characterized in that, The ratio of the shortest distance between the second metal body and the first metal body to the thickness of the insulator is greater than or equal to 5 and less than or equal to 25.

7. The temperature sensing structure according to claim 2, characterized in that, The thickness of the insulator is less than 1 μm.

8. The temperature sensing structure according to claim 1, characterized in that, In one longitudinal direction, the shortest distance between the temperature sensing element and the object to be measured is less than the shortest distance between the temperature sensing element and the insulator.

9. The temperature sensing structure according to claim 1, characterized in that, The first metal body is conformally disposed on the temperature sensing element.

10. The temperature sensing structure according to claim 2, characterized in that, The first metal body includes a first surface and a second surface opposite to each other, the first surface being away from the temperature sensing element. The third metal body includes a third surface and a fourth surface opposite to each other, the third surface being connected to the insulator, and the flatness of the third surface being greater than that of the first surface.

11. The temperature sensing structure according to claim 1, characterized in that, The temperature sensing element is one of a bipolar junction transistor, a diode, and a resistor.

12. The temperature sensing structure according to claim 1, characterized in that, The temperature sensing element is a first bipolar junction transistor (BJT), the object under test is a second BJT, and the heat conduction component is coupled between an emitter of the first BJT and a collector of the second BJT.

13. The temperature sensing structure according to claim 1, characterized in that, The heat conduction component further includes a through hole and a fifth metal body, wherein the second metal body is coupled to the test object through the through hole and the fifth metal body.

14. The temperature sensing structure according to claim 1, characterized in that, The equivalent capacitance of the metal-insulator-metal structure is greater than or equal to 50fF and less than or equal to 300fF.

15. The temperature sensing structure according to claim 2, characterized in that, The contact area between the insulator and the third metal body is greater than or equal to 86 μm. 2 And less than or equal to 530μm 2 .

16. The temperature sensing structure according to claim 1, characterized in that, The device under test is an amplifier element.

17. The temperature sensing structure according to claim 1, characterized in that, The temperature sensing element is made of gallium arsenide.

18. The temperature sensing structure according to claim 1, characterized in that, The temperature sensing element is a first bipolar junction transistor (BJT). The first BJT includes a collector and a base stacked along a thickness direction. The collector has a first side surface close to the object under test and a second side surface away from the object under test. In a length direction perpendicular to the thickness direction, the shortest distance between the first side surface of the collector and the geometric center of the base is less than the shortest distance between the second side surface of the collector and the geometric center of the base.

19. The temperature sensing structure according to claim 18, characterized in that, The object under test is a second bipolar junction transistor, and in the length direction, the distance between an emitter of the first bipolar junction transistor and a collector of the second bipolar junction transistor is less than 12 μm.

20. A radio frequency circuit, characterized in that, include: An amplifier component; as well as A temperature sensing structure for sensing the temperature of the amplifier element, the temperature sensing structure comprising: A temperature sensing element; and A heat conduction component is coupled between the temperature sensing element and the amplifier element to conduct heat, the heat conduction component comprising: A first metal body is coupled to the temperature sensing element; A second metal body, coupled to the amplifier element; and A metal-insulator-metal structure is connected between the first metal body and the second metal body.

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