Temperature Sensing Structure and Radio Frequency Circuit

Abstract

To provide a temperature sensing structure that can significantly reduce the time it takes for thermal energy of an object under test to be conducted to a temperature sensing element, thereby increasing the overall amount of heat transfer. The temperature sensing structure (100) includes a temperature sensing element (TS) and a thermally conductive component (TC). The thermally conductive component is coupled for thermal conduction between the temperature sensing element and an object under test (102). The thermally conductive component includes a first metal body (104), a second metal body (106), and a metal-insulator-metal structure (108). The first metal body is coupled to the temperature sensing element, the second metal body is coupled to the object under test, and the metal-insulator-metal structure is connected between the first metal body and the second metal body.

Description

[Technical Field]

[0001] The present disclosure relates to temperature sensing structures and radio frequency circuits. [Background technology]

[0002] In technologies where radio frequency (RF) power amplifiers (PAs) are regulated by an external controller, a temperature sensor must be employed. In the gallium arsenide (GaAs) process used to manufacture temperature sensors, GaAs has a lower thermal conductivity and a slower thermal conduction speed than silicon (Si). Therefore, placing a temperature sensor next to the power amplifier may simply result in a time difference between the temperature detection of the power amplifier and the temperature sensor due to the thermal conductivity characteristics of the GaAs material, which may delay the external controller receiving the temperature detection results. In this way, the external controller may not be able to regulate the power amplifier in a timely manner. Summary of the Invention

[0003] The present disclosure provides a temperature sensing structure that can significantly reduce the time it takes for thermal energy from an object being tested to be conducted to a temperature sensing element, increasing the overall amount of heat transfer.

[0004] The present disclosure further provides a radio frequency circuit that can be configured to improve the performance of a radio frequency power amplifier.

[0005] In one embodiment of the present disclosure, a temperature sensing structure is configured to sense the temperature of an object under test. The temperature sensing structure includes a temperature sensing element and a thermally conductive component. The thermally conductive component is coupled for thermal conduction between the temperature sensing element and the object under test. The thermally conductive 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 under test. The metal-insulator-metal structure is connected between the first metal body and the second metal body.

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

[0007] In order to make the foregoing features of the present disclosure comprehensible, exemplary embodiments will now be described in detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of a temperature sensing structure according to a first embodiment of the present disclosure. [Figure 2] FIG. 10 is a cross-sectional view of a temperature sensing structure according to a second embodiment of the present disclosure. [Figure 3] FIG. 10 is a cross-sectional view of a temperature sensing structure according to a third embodiment of the present disclosure. [Figure 4] FIG. 4 is a top view of a portion of the temperature sensing structure of FIG. 3. [Figure 5] FIG. 10 is a schematic diagram of a radio frequency circuit according to a fourth embodiment of the present disclosure. [Figure 6] FIG. 10 is a schematic diagram of a radio frequency circuit according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Fig. 1 is a cross-sectional view of a temperature sensing structure according to a first embodiment of the present disclosure. In Fig. 1, the temperature sensing structure 100 of the first embodiment is configured to sense the temperature of an object to be tested 102. The temperature sensing structure 100 may generally be formed on a substrate 101, and the object to be tested 102 and the temperature sensing structure 100 may be formed on the same substrate 101, although the present disclosure is not limited thereto.

[0010]

[0023] Please continue to refer to FIG. 1. The temperature sensing structure 100 includes a temperature sensing element TS and a heat conduction component TC. The temperature sensing element TS may be an element configured to detect temperature, such as a bipolar junction transistor, a diode, a resistor, or other suitable element. For example, if a bipolar junction transistor is employed as the temperature sensing element TS, the temperature of the object 102 under test may be obtained through a voltage change in the base-emitter bias voltage. In another embodiment, if a diode is employed as the temperature sensing element TS, the temperature of the object 102 under test may be obtained through a voltage change in the forward bias of the diode. Furthermore, if a resistor is employed as the temperature sensing element TS, the temperature of the object 102 under test may be obtained through a change in the resistance value.

[0011] A thermally conductive component TC is coupled between the temperature sensing element TS and the object under test 102 for thermal conduction. The thermally conductive 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 under test 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 the thickness direction. The insulator 112 is connected between the third metal body 110 and the fourth metal body 114. Since 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, the temperature of the object under test 102 is conducted to the temperature sensing element TS through the thermal conduction component TC including the above structure. Compared to a temperature sensing device without the metal-insulator-metal structure 108, the thermal conduction time of the thermal conduction component TC including the metal-insulator-metal structure 108 can be reduced by about 1000 times and the heat transfer can be increased by about 1000 times.

[0012] In FIG. 1 , the shortest distance d1 in the thickness direction between the second metal body 106 and the first metal body 104 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 can be 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 conducting component TC is too long, which is unfavorable for heat conduction. If the ratio (d1 / t) is greater than 25, a short circuit may occur. Although FIG. 1 shows that the fourth metal body 114 and the second metal body 106 are separate structures, the present disclosure is not limited thereto. The fourth metal body 114 and the second metal body 106 may be integrally formed on the first metal body 104 and the third metal body 110 through a process, and 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 in the thickness direction than the second metal body 106. Furthermore, to enable the thermal conduction component TC to more effectively conduct the temperature of the object under test 102, the thermal conduction component TC may further include a conductive via 116 and a fifth metal body 118, and the second metal body 106 is coupled to the object under test 102 through the conductive via 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 may be manufactured using the same process. For example, the fifth metal body 118, the first metal body 104, and the third metal body 110 are all first metal layers (also referred to as M1) in a semiconductor device, and different circuit portions may be defined through a photomask process, but the present disclosure is not limited thereto. In other embodiments, the formation step of the fifth metal body 118 may be different from the formation steps of the first metal body 104 and the third metal body 110. Also, although the figure shows a film layer covering the temperature sensing element TS and the heat conduction component TC with a single dielectric layer 120, the entire dielectric layer 120 may be composed of several layers of dielectric material.

[0013] In one embodiment, the thickness t of the insulator 112 may be less than 1 μm, e.g., less than 0.5 μm, to promote heat conduction. Meanwhile, the thickness t of the insulator 112 only needs to be sufficient to electrically isolate the direct current (DC) operation of the object 102 under test. In one embodiment considering RF applications, the equivalent capacitance value of the metal-insulator-metal structure 108 may be greater than or equal to 50 fF and less than or equal to 300 fF. Alternatively, the contact area between the insulator 112 and the third metal body 110 may be less than or equal to 86 μm 2 More than 530μm 2 The thermal conductivity of the thermally conductive component TC with the metal-insulator-metal structure 108 can be as low as or less than 0.5%. Compared with a temperature sensing device without the metal-insulator-metal structure 108, the thermal conductivity of the thermally conductive component TC with the metal-insulator-metal structure 108 can only change the operating current of the object under test 102 by 0.5%. Furthermore, regardless of whether the signal is high-power or low-power, the change in the operating power of the object under test 102 is less than 0.3%, indicating, but not limited to, that the metal-insulator-metal structure 108 has a very small effect on the object under test 102. In an embodiment not considering RF applications, the equivalent capacitance value of the metal-insulator-metal structure 108 can be increased or decreased according to requirements. Alternatively, the contact area between the insulator 112 and the third metal body 110 can be increased or decreased according to requirements.

[0014] Refer again to FIG. 1 . The insulator 112 does not overlap the temperature sensing element TS. In other words, in the cross-sectional view, the shortest longitudinal distance d3 between the insulator 112 and the temperature sensing element TS is at least greater than 0. In some embodiments, the shortest longitudinal distance d2 between the temperature sensing element TS and the object to be tested 102 can be shorter than the shortest longitudinal distance d3 between the temperature sensing element TS and the insulator 112, i.e., the temperature sensing element TS is positioned closer to the object to be tested 102 in the longitudinal direction and is spaced a relatively long distance from the metal-insulator-metal structure 108. The longitudinal direction is, for example, parallel to the surface of the substrate 101 (e.g., the top surface closer to the temperature sensing element TS or the object to be tested 102, or the bottom surface farther from the temperature sensing element TS or the object to be tested 102) and perpendicular to the thickness direction. The cross-sectional view is, for example, in a reference plane formed by the thickness direction and the longitudinal direction. A temperature sensing element TS closer to the object 102 under test further reduces the element area and increases the sensing speed by shortening the heat conduction distance. In another embodiment, although FIG. 1 does not show the detailed structure of the temperature sensing element TS, the surface of the temperature sensing element TS may not be flat. If the metal-insulator-metal structure 108 were disposed directly on the surface of the temperature sensing element TS, the metal-insulator-metal structure 108 could cause the thinner insulator 112 to break in the uneven or sloped areas, as will be explained in the paragraph describing FIG. 2 below. Therefore, to form the metal-insulator-metal structure 108 on a flatter surface away from the temperature sensing element TS, in the present disclosure, the shortest longitudinal distance d3 between the metal-insulator-metal structure 108 and the temperature sensing element TS is greater than the shortest longitudinal distance d2 between the temperature sensing element TS and the object 102 under test, which may further improve the reliability of the metal-insulator-metal structure 108.

[0015] FIG. 2 is a cross-sectional view of a temperature sensing structure according to a second embodiment of the present disclosure, in which the same reference numerals as in FIG. 1 are used to indicate the same or similar parts and components, and the relevant descriptions of the same or similar parts may also refer to the description of FIG. 1 and will not be repeated here.

[0016] In FIG. 2 , the temperature sensing structure 100′ includes a temperature sensing element TS and a thermal conduction component TC′. In some embodiments, the material of the temperature sensing element TS can include gallium arsenide (GaAs), such as a gallium arsenide bipolar junction transistor (BJT), which can include a collector C1, a base B1, and an emitter E1. The emitter E1 is located on the base B1, and the base B1 is located on the collector C1. The thermal conduction component TC′ is coupled between the emitter E1 of the temperature sensing element TS and the object under test 102 for thermal conduction. The thermal conduction component TC′ includes a first metal body 200, a second metal body 202, and a metal-insulator-metal structure 204. 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 may be conformally disposed on the temperature sensing element TS and coupled to the emitter E1 through a via v1 formed in the dielectric layer 210. In some embodiments, the fifth metal body 118 may also be coupled to the object under test 102 through another via v2 formed in the dielectric layer 210, the conductive via 116 and the fourth metal body 208 may be formed in the dielectric layer 212, and the second metal body 202 may be formed in the dielectric layer 214 on top of the dielectric layer 212. However, the present disclosure is not limited thereto.

[0017] Continuing to refer to FIG. 2 , the first metal body 200 includes a first surface s1 and a second surface s2 that are opposite each other. The first surface s1 is distant from the temperature sensing element TS. The third metal body 206 includes a third surface s3 and a fourth surface s4 that are opposite each other. The third surface s3 is connected to the insulator 112. Because the surface shape of the temperature sensing element TS is not perfectly planar, the first surface s1 conformally formed on the surface is not flat. In contrast, because the area where the third metal body 206 is deposited is flatter, the flatness of the third surface s3 of the third metal body 206 can be made greater than the flatness of the first surface s1 to ensure that the metal-insulator-metal structure 204 is not detached, thereby improving the structural stability of the temperature sensing structure 100′ of the present disclosure. In the second embodiment, the shapes and sizes 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, but still satisfy the condition that the shortest distance d1 in the thickness direction between the second metal body 202 and the first metal body 208 is greater than the thickness t of the insulator 112. Furthermore, the range of the ratio (d1 / t) of the shortest distance d1 to the thickness t, 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, etc., may all be set to the same as in the first embodiment, or may be adjusted to be larger or smaller as necessary.

[0018] Figure 3 is a cross-sectional view of a temperature sensing structure according to a third embodiment of the present disclosure, in which the same reference numerals as in Figure 1 are used to indicate the same or similar parts and components, and the same or similar parts and components may also refer to the description of Figure 1, which will not be repeated here. Figure 4 is a top view of a portion of the temperature sensing structure of Figure 3, with some components omitted for clarity.

[0019] Please refer to Figures 3 and 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 to be tested 102 is a second bipolar junction transistor. The temperature sensing element TS includes at least a collector C1, a base B1, and an emitter E1 stacked along the thickness direction. The emitter E1 is disposed on the base B1. The collector C1 has a first side cs1 close to the object to be tested 102 and a second side cs2 away from the object to be tested 102. The object to be tested 102 includes at least a collector C2, a base B2, and an emitter E2. 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 surface cs1 of the collector C1 and the geometric center GC of the base B1 is smaller than the shortest distance d6 between the second side surface cs2 of the collector C1 and the geometric center GC of the base B1. In other words, the temperature sensing element TS in the temperature sensing structure 100″ of the third embodiment is an asymmetric bipolar junction transistor. Compared with a typical symmetric bipolar junction transistor, in the third embodiment, the distance d4 (lengthwise) between the emitter E1 of the temperature sensing element TS and the collector C2 of the object under test 102 is reduced by using the asymmetric temperature sensing element TS, thereby shortening the heat conduction distance and further reducing the element area. The distance d4 between the emitter E1 and the collector C2 can be, for example, but not limited to, less than 12 μm.

[0020] Continuing to refer to FIG. 3 , a thermally conductive component TC″ may be formed on the dielectric layer 300 and connected to the emitter E1 through a via v1 in the dielectric layer 300 and to the collector C2 through a via v2 in the dielectric layer 300. The thermally conductive 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 of the previous embodiment and includes 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 may be formed together on the dielectric layer 300 through a process, while the second metal body 304 may be formed on a dielectric layer 308 covering the first metal body 302 and the third metal body 110. The insulator 112 of the metal-insulator-metal structure 306 may be formed within the dielectric layer 308. A fourth metal body 114 may be formed on the insulator 112 .

[0021] 5 and 6 are diagrams of radio frequency circuits according to fourth and fifth embodiments of the present disclosure, respectively.

[0022] In FIG. 5 , the radio frequency circuit includes an amplifying element PA and a temperature sensing structure, for example, the temperature sensing structure 100″ in the third embodiment. The temperature sensing structure 100″ includes a temperature sensing element and a heat conducting component. The temperature sensing element TS is, for example, the temperature sensing element TS in the first to third embodiments described above. The temperature sensing element TS can detect the temperature of the amplifying element PA. The temperature sensing element TS is connected to a power supply voltage V DD The amplifier element PA is connected to the power supply voltage V CC The aforementioned thermal conduction component is, for example, the thermal conduction component TC″ in the third embodiment, and the metal-insulator-metal structure MIM may prevent the DC signal 500 from coupling to the temperature sensing element TS, but may allow most of the heat flow 502 to reach the temperature sensing element TS through the thermal conduction component TC″.

[0023] 6, the radio frequency circuit includes an amplifying element PA and a temperature sensing structure 100"", which includes a temperature sensing element TS and a thermal conduction component TC"", where the temperature sensing element TS is, for example, the temperature sensing element TS in the first to third embodiments above. The difference between the thermal conduction component TC"" in FIG. 6 and the thermal conduction component TC" in FIG. 5 is that the metal-insulator-metal structure MIM in FIG. 5 is shown implemented as a capacitor 600, which may prevent the DC signal 500 from coupling to the temperature sensing element TS but allow most of the heat flow 502 to reach the temperature sensing element TS through the thermal conduction component TC"".

[0024] Although the present disclosure has been disclosed in the above embodiments, it is not intended to limit the present disclosure. Those skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure should be defined by the scope of the attached utility model registration claims.

Claims

1. 1. A temperature sensing structure configured to sense a temperature of an object to be tested, comprising: a temperature sensing element; and a thermally conductive component coupled for thermal conduction between the temperature sensing element and the object under test, the component comprising: a first metallic body coupled to the temperature sensing element; a second metal body coupled to the object under test; and a metal-insulator-metal structure connected between the first metal body and the second metal body; a heat conducting component; Temperature sensing structure.

2. the metal-insulator-metal structure includes a third metal body, an insulator, and a fourth metal body, and the insulator is connected between the third metal body and the fourth metal body. The temperature sensing structure of claim 1 .

3. the third metal body is connected to the first metal body, and the fourth metal body is connected to the second metal body; The temperature sensing structure of claim 2 .

4. the insulator does not overlap the temperature sensing element in a reference plane defined by the thickness direction and the length direction; The temperature sensing structure of claim 3 .

5. a shortest distance between the second metal body and the first metal body in the thickness direction is greater than a thickness of the insulator; The temperature sensing structure of claim 4 .

6. a 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; The temperature sensing structure of claim 5 .

7. The thickness of the insulator is less than 1 μm. The temperature sensing structure of claim 2 .

8. the shortest distance in the length direction between the temperature sensing element and the object under test is shorter than the shortest distance between the temperature sensing element and the insulator; The temperature sensing structure of claim 2 .

9. the first metal body is conformally disposed over the temperature sensing element; The temperature sensing structure of claim 1 .

10. the first metal body has a first surface and a second surface opposite each other, the first surface being remote from the temperature sensing element; the third metal body has a third surface and a fourth surface opposite each other, the third surface being connected to the insulator, and the flatness of the third surface being greater than the flatness of the first surface; The temperature sensing structure of claim 2 .

11. the temperature sensitive element is one of a bipolar junction transistor, a diode, and a resistor. The temperature sensing structure of claim 1 .

12. the temperature sensitive element is a first bipolar junction transistor, the object under test is a second bipolar junction transistor, and the heat conducting component is coupled between an emitter of the first bipolar junction transistor and a collector of the second bipolar junction transistor; The temperature sensing structure of claim 1 .

13. a conductive via and a fifth metallic body, the second metallic body being coupled to the object under test through the conductive via and the fifth metallic body; The temperature sensing structure of claim 1 .

14. The equivalent capacitance value of the metal-insulator-metal structure is 50 fF or more and 300 fF or less. The temperature sensing structure of claim 1 .

15. The contact area between the insulator and the third metal body is 86 μm 2 More than 530μm 2 Below is the The temperature sensing structure of claim 2 .

16. the object to be tested is an amplifying element; The temperature sensing structure of claim 1 .

17. the material of the temperature sensing element includes gallium arsenide; The temperature sensing structure of claim 1 .

18. the temperature sensing element is a first bipolar junction transistor, the first bipolar junction transistor having a collector and a base stacked along a thickness direction, the collector having a first side closer to the object under test and a second side farther from the object under test, and a shortest distance between the first side of the collector and a geometric center of the base in a length direction perpendicular to the thickness direction is smaller than a shortest distance between the second side of the collector and the geometric center of the base; The temperature sensing structure of claim 1 .

19. the object to be tested is a second bipolar junction transistor, and the distance between the emitter of the first bipolar junction transistor and the collector of the second bipolar junction transistor in the length direction is less than 12 μm; 20. The temperature sensing structure of claim 18.

20. 1. A radio frequency circuit comprising: an amplifying element; and a temperature sensing structure configured to sense a temperature of the amplifying element, the temperature sensing structure comprising: a temperature sensing element; and a thermal conduction component coupled for thermal conduction between the temperature sensing element and the amplifying element, the thermal conduction component comprising: a first metallic body coupled to the temperature sensing element; a second metal body coupled to the gain element; and a metal-insulator-metal structure connected between the first metal body and the second metal body; a heat conducting component; Radio frequency circuits.

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