Wireless wafer temperature measuring device based on heat insulation filling material

Abstract

The invention discloses a wireless wafer temperature measuring device based on a heat insulation filling material, and relates to the technical field of semiconductor testing equipment. The device is mainly used for measuring the distribution of a wafer surface temperature field in a semiconductor equipment processing process, and comprises a wafer shell, a temperature measuring circuit and an electronic device heat insulation part, the temperature measurement circuit has the functions of temperature measurement data acquisition, data storage and data transmission; according to the electronic device heat insulation part, a heat insulation material is used for wrapping a non-high-temperature-resistant part of the temperature measurement circuit, so that heat transferred from the surface of a wafer to the part is reduced. The method is compatible with the process, accurate in measurement, low in cost, high in safety and high in commercial value.

Description

Technical Field

[0001] This invention relates to the field of semiconductor testing equipment technology, and in particular to a wireless wafer temperature measurement device based on thermal insulation filling material, used for temperature monitoring in semiconductor processing equipment. Background Technology

[0002] Semiconductor manufacturing involves the control of various parameters, including gas flow rate, pressure, time, and temperature. Among these parameters, temperature is present throughout the entire process and is a crucial factor that the industry invests significant effort in measuring and controlling. Wafer temperature directly affects the quality and stability of various process steps on the wafer. For example, in plasma etching, uneven temperature leads to inconsistent etching rates, resulting in defects in the etched contours. Furthermore, temperature significantly impacts photoresist during etching; excessively high temperatures can soften and deform the photoresist, causing deviations in the etched pattern; in severe cases, the photoresist can carbonize, making it difficult to remove after etching.

[0003] Currently, wafer temperature measurement products can be categorized into wired and wireless types based on their communication methods. Wired wafer temperature measurement systems utilize thermocouple technology for real-time wafer temperature measurement. However, the internally introduced thermocouples can affect the wafer temperature field distribution during measurement, necessitating frequent factory calibration of the wired wafer temperature measurement system. Furthermore, in semiconductor processing, some instruments operate in sealed, low-vacuum chambers, making wired wafer temperature measurement systems incompatible with these devices, resulting in expensive equipment modifications and lengthy engineering processes. Wireless wafer temperature measurement systems overcome these shortcomings. They utilize integrated IC temperature sensors, compatible with wafer materials. Their system circuitry, including power supply, communication, control, and temperature measurement circuits, is integrated into a single wafer, eliminating the need to modify the processing equipment. For example, during deep silicon etching, wafer temperatures can reach 200°C, exceeding the normal operating temperature limits of many electronic devices. In severe cases, this can lead to explosions, damaging processing equipment and even causing injuries or fatalities to engineers and researchers. Patents US20120287574A1 and CN116598228A use vacuum chambers for heat insulation. However, the process of making a vacuum chamber is complex and it is difficult to achieve a high degree of vacuum inside. The manufacturing process is complicated and the cost is high.

[0004] Therefore, this paper proposes a wireless wafer temperature measurement system that uses high-efficiency thermal insulation material instead of vacuum insulation. Summary of the Invention

[0005] This invention provides a wireless wafer temperature measurement device, which includes: a wafer shell, a flexible PCB temperature measurement circuit, and heat insulation material. Details are as follows:

[0006] Preferably, the wafer shell includes a surface silicon wafer I, a surface silicon wafer II, and an intermediate silicon wafer layer, wherein the surface silicon wafer I and the surface silicon wafer II can be single-sided polished silicon wafers, and the wafer shell composed of the three can prevent metal contamination during the processing.

[0007] More preferably, the thickness of the intermediate silicon wafer layer can be set according to actual needs. When the thickness is large, a high-temperature bonding process can be used to bond multiple thinner silicon wafer layers one by one to form a silicon wafer layer of the required thickness.

[0008] Preferably, the temperature measurement system includes: a sensor temperature measurement unit, a microcontroller unit, a wireless communication unit, a storage unit, and a power supply unit, which are made of flexible printed circuit board (FPC) material with a thickness of 0.1 mm. The sensor connection end is in the shape of a long straight arm to minimize the influence of the circuit board on the temperature between the sensor arrays.

[0009] Preferably, the insulation material is a high-efficiency insulation material, in the form of a colloid, and its volume remains essentially unchanged after solidification.

[0010] More preferably, the thermal conductivity of the insulation material is 0.01-0.025 W / mK, which reduces the heat conduction from the wafer surface to the internal high-temperature-resistant circuits, thereby ensuring that the internal circuits do not exceed the limit temperature when operating normally.

[0011] More preferably, an infrared shielding agent can be added inside the material. The infrared shielding agent is selected from carbon black and TiO. Adding an infrared shielding agent can reduce the radiative heat transfer from the wafer surface to the internal high-temperature-resistant circuits.

[0012] As described above, the wireless wafer temperature measurement device of the present invention has the following beneficial effects:

[0013] The wireless wafer temperature measurement device of the present invention, which incorporates internal heat insulation material, is placed in semiconductor processing equipment along with the wafer to be processed in a co-processing manner. This wireless wafer temperature measurement device can measure and record the temperature distribution of the wafer during the processing. After processing is completed, the measurement data can be sent to a host computer. Engineers can analyze the processing results and measurement data to improve some processing parameters and ultimately improve the yield of wafer etching products. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a wireless wafer temperature measurement device.

[0015] Figure 2 This is a distribution diagram of the sensors in a wireless wafer temperature measurement device.

[0016] Figure 3 This is a schematic diagram of the sensor fixing in a wireless wafer temperature measurement device.

[0017] Figure 4 This is a cross-sectional view of a wireless wafer temperature measurement device.

[0018] Figure 5 This is a schematic diagram of the communication method of the wireless wafer temperature measurement device.

[0019] In the diagram: 1 - Silicon shell structure, 2 - Thermal insulation material, 3 - Flexible PCB circuit board, 4 - Surface silicon wafer I, 5 - Middle silicon ring, 6 - Surface silicon wafer II, 7 - Power supply, 8 - IC integrated temperature sensor, 9 - Copper antenna, 10 - High temperature adhesive, 11 - High temperature resistant fine wire, 12 - Memory chip, 13 - Main control chip, 14 - Reader, 15 - Host computer. Detailed Implementation

[0020] First, the surface silicon wafer I (4) and the sensor (8) of the FPC circuit are arranged according to... Figure 3 They are assembled in a certain way.

[0021] Then, in a low-temperature environment, the intermediate silicon wafer layer (5) is bonded to the surface silicon wafer I (4).

[0022] Secondly, the rectangular area etched through the middle of the intermediate silicon wafer layer (5) is slightly larger than the middle area of ​​the circuit board. The heat insulation colloid is injected into the bottom of the circuit board using a syringe. The amount used during injection is calculated as the product of the sensor thickness and the middle area of ​​the circuit board.

[0023] Then, wait for the insulation material to cure, and then use high-temperature resistant wires to connect the power supply to the power interface of the circuit board. The number of power supplies can be selected according to the actual power of the temperature measurement system.

[0024] Finally, the surface silicon wafer II is bonded to the preceding assembly at low temperature.

[0025] Figure 2 This diagram illustrates the sensor distribution of a wireless wafer temperature measurement device. It is a simplified representation and may not be an actual image; it serves only to show the internal sensor layout and locations. A suitable set of concentric circles needs to be selected to ensure a uniform temperature measurement area for each sensor. Proper sensor arrangement avoids redundant wafer temperature measurements, thus achieving wafer temperature measurement without increasing the number of sensors. For example, when the wafer size is 4 inches and there are 16 sensors, each sensor should measure a range of 4.9 cm. 2 .

[0026] Figure 3A schematic diagram of the sensor fixing of the wireless wafer temperature measurement device. The temperature sensor (8) in the temperature detection circuit uses an IC integrated sensor, and is attached to the lower surface of the surface silicon wafer I (4) or a groove on the lower surface of the surface silicon wafer I (4) using an insulating, high thermal conductivity, and high temperature resistant adhesive (10). The type of high temperature resistant thermally conductive adhesive can be selected according to actual needs, for example, silicone, polyimide (PI) adhesive, thermosetting adhesive, and graphite thermally conductive adhesive are preferred.

[0027] Figure 4 A cross-sectional view of the wireless wafer temperature measurement device. The composition of the temperature measurement system circuit is described in detail. The temperature measurement system circuit includes: a temperature detection circuit, a control circuit, a wireless communication circuit, a storage circuit, and a power supply circuit.

[0028] The FPC has a thickness of 0.1mm and the sensor connection end is a long straight arm shape, which can reduce the influence of the FPC on the temperature of temperature sensors at different locations.

[0029] To further explain, Figure 4 The power supply (7) is located on the upper surface of the surface silicon wafer II (6). Since the surface silicon wafer II is in direct contact with the cooling of the instrument during the instrument processing, it can provide a more suitable temperature environment for the power supply to work. For safety reasons, the selected power supply can also be a high-temperature resistant button lithium battery, a high-temperature resistant thin film battery, etc.

[0030] To further explain, based on the power consumption requirements of the circuit, the voltage and current of the circuit, multiple power supplies can be used. For example, different circuit functions can select appropriate power supplies according to their circuit requirements. In this patent example, the number of power supplies is 4.

[0031] Figure 5 A schematic diagram of the communication method of the wireless wafer temperature measurement device. This invention uses radio frequency identification (RFID) technology in the communication mode selection of the wireless communication circuit, which includes a reader (14) and a host computer (15). The host computer (14) controls the device startup and data transmission. Since the presence of radio frequency voltage during the use of plasma etching instruments makes radio frequency wireless communication particularly difficult, this invention uses a "store first, read later" method for wireless wafer temperature measurement data.

[0032] Specifically, the wireless wafer temperature measurement device is placed in front of the processing chamber and given instructions to store the collected data. When storing the data, it is necessary to determine whether the continuously collected data needs to be stored and to make reasonable use of the existing storage space, thereby extending the usage time.

[0033] After processing, simply take out the device of the present invention and place it above the reader (14), then connect it to the host computer, give relevant instructions, and perform operations such as reading data, processing data, and visualizing data.

[0034] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make reasonable improvements within the scope of the patent claims without affecting the substantive content of the present invention.

Claims

1. A wireless wafer temperature measurement device, characterized in that: The wafer shell (1), the heat insulation material (2), and the temperature measuring system (3) are characterized in that: the wafer shell (1) is a silicon shell with an internal cavity, which isolates the heat insulation material (2) and the temperature measuring system (3) from the internal environment of the semiconductor equipment; the heat insulation material (2) forms a cavity to enclose the circuit devices of the temperature measuring system (3) that are not resistant to high temperatures, thereby ensuring the normal operation of the temperature measuring system (3) during the measurement process; the temperature sensor in the temperature measuring system (3) is located between the wafer shell (1) and the heat insulation material (2), ensuring that the temperature of the silicon wafer can be accurately measured.

2. The wireless wafer temperature measuring device according to claim 1; characterized in that, The wafer shell (1) is formed sequentially from a surface silicon wafer I (4), an intermediate silicon wafer layer (5), and a surface silicon wafer II (6) to form a wafer shell with one or more cavities inside.

3. The wireless wafer temperature measuring device according to claim 1, characterized in that, The heat insulation material (2) is characterized in that it is located inside the cavity of the silicon wafer shell (1) and has a layered structure with an internal cavity.

4. The wireless wafer temperature measuring device according to claim 1, characterized in that, The temperature measurement system (3) includes a sensor temperature measurement unit, a microcontroller unit, a wireless communication unit, a storage unit, and a power supply unit.

5. The cavity according to claim 2, characterized in that, The sealed cavity formed by the wafer shell can have a vacuum degree.

6. The cavity of the thermal insulation material according to claim 3, characterized in that, The cavity is a non-sealed space with one or more through holes on one side for connecting the wires of the temperature measurement system (3).

7. The temperature measuring system (3) according to claim 4, characterized in that, The temperature measuring unit is located outside the cavity described in claim 3, while the microcontroller unit, wireless communication unit, storage unit, and power supply unit, which are not resistant to high temperatures, are located inside the cavity described in claim 3.

8. The temperature measuring system (3) according to claim 4, characterized in that, The temperature measuring unit is closely fitted to the cavity surface of the surface silicon wafer I (4).

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