Focus ring alignment measurement device, system, method, and plasma processing device

Abstract

The application discloses a focusing ring alignment measuring device, a system, a method and a plasma processing device, and relates to the technical field of plasma processing devices, in particular to a focusing ring alignment measuring device, a system, a method and a plasma processing device. The focusing ring alignment measuring device comprises a plate-shaped main body, a positioning structure arranged on the plate-shaped main body and a sensor arranged on the plate-shaped main body and used for emitting a signal to an inner side surface of the focusing ring. During measurement, the plate-shaped main body is placed on an electrostatic chuck, positioning between the plate-shaped main body and the electrostatic chuck is realized through the positioning structure, and an offset of the focusing ring relative to the center of the electrostatic chuck is measured through signal feedback of multiple positions of the inner side surface of the focusing ring. The application solves the problems of low efficiency and high cost of replacing the focusing ring in the prior art without opening the cavity, and the problem that the focusing ring cannot be controlled to be neutral without opening the cavity.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process equipment technology, and specifically to a focusing ring alignment measurement device, system, method, and plasma processing device. Background Technology

[0002] In the manufacturing process of semiconductor devices, plasma etching is a key process for processing wafers into designed patterns. Existing plasma processing equipment includes capacitively coupled plasma etching (CCP) equipment and inductively coupled plasma etching (ICP) equipment. Due to their simple structure and relatively low cost, inductively coupled plasma (ICP) etching equipment and capacitively coupled plasma (CCP) etching equipment are widely used in the field of dry etching.

[0003] In the plasma processing device, the plasma density distribution is directly proportional to the etching rate of the wafer to be processed; the higher the plasma density, the higher the etching rate, and vice versa. Due to the combined effect of the plasma gas flow and the area of ​​the upper and lower electrodes, the plasma density is high in the central region of the wafer to be processed and low at the edges, resulting in a higher etching rate in the central region than at the edges, leading to uneven etching rates on the wafer.

[0004] To address the aforementioned issues, a focusing ring is positioned around the wafer to be processed. This effectively expands the radius of the lower electrode outward, resulting in plasma of the same concentration at the wafer edge as at the center. This helps ensure the uniformity of the etching process between the edge and center regions.

[0005] Silicon or silicon carbide is typically used as the material for the focusing ring. As the etching process time increases, the surface of the focusing ring is also consumed by the plasma etching, reducing the surface height of the focusing ring. This causes the plasma sheath layer above the focusing ring to shift downwards, resulting in poor etching collimation in the edge area of ​​the substrate to be processed. In this case, the focusing ring should not be used anymore.

[0006] In existing technologies, it is usually necessary to open a cavity to remove the focusing ring and replace it with a new one. However, the process of opening a cavity for maintenance consumes a lot of manpower and time, resulting in low efficiency and high cost. The alignment requirements between the reinstalled focusing ring and the center of the electrostatic chuck are quite high, and the existing method is to use a feeler gauge to estimate the alignment.

[0007] Furthermore, if the focusing ring is installed in the plasma processing equipment without opening a cavity and instead using an end effector to transfer the plate, the centering of the focusing ring cannot be measured. After installation, there is an annular gap between the electrostatic chuck and the focusing ring. This gap is related to whether the focusing ring is concentric with the base, which in turn affects the uniformity of the etching process and the tilting of the edges.

[0008] Therefore, there is an urgent need for a device and method to obtain the degree of alignment between the focusing ring and the electrostatic chuck without opening a cavity. Summary of the Invention

[0009] The purpose of this invention is to provide a focusing ring alignment measurement device, system, method, and plasma processing device, which solves the problems of low efficiency and high cost of opening a cavity to replace the focusing ring in the prior art, and the inability to control the centering when replacing it without opening a cavity.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A focusing ring alignment measurement device for a plasma processing apparatus, the plasma processing apparatus including a reaction chamber and an electrostatic chuck located within the reaction chamber, characterized in that it includes:

[0012] plate-like body;

[0013] A positioning structure is provided on the plate-shaped main body;

[0014] A sensor, mounted on the plate-shaped body, is used to transmit signals to the inner surface of the focusing ring;

[0015] During measurement, the plate-shaped body is placed on the electrostatic chuck, and the positioning structure is used to position the plate-shaped body relative to the center of the electrostatic chuck. The offset of the focusing ring relative to the center of the electrostatic chuck is measured by signal feedback from multiple positions on the inner side of the focusing ring.

[0016] Optionally, the positioning structure matches the positioning part for positioning the wafer provided on the electrostatic chuck, thereby realizing the positioning between the plate-shaped body and the electrostatic chuck.

[0017] Optionally, the number of sensors is at least three, and they are evenly or non-uniformly spaced in the circumferential direction of the plate-shaped body.

[0018] Optionally, the sensor is used to measure the distance between the focusing ring alignment device and the focusing ring, so as to determine the offset of the focusing ring based on the measurement results of at least three of the sensors.

[0019] Optionally, the sensor is a laser image sensor or a distance sensor.

[0020] A focusing ring alignment measurement system includes the focusing ring alignment measurement device as described above, and further includes: a communicator and a processor;

[0021] The communicator is disposed on the plate-shaped main body, and the processor is disposed outside the cavity of the plasma processing device. The communicator is communicatively connected to the sensor and the processor and is used to transmit the measurement results of the sensor to the processor. The processor is used to determine the offset of the focusing ring based on the measurement results.

[0022] Optionally, the focusing ring alignment measurement system further includes a display, which is communicatively connected to the processor, for displaying the measurement results of the sensor and / or the offset of the focusing ring, the display being located outside the cavity.

[0023] A focusing ring alignment measurement method, comprising:

[0024] The focusing ring alignment measuring device, as described above, is placed on the electrostatic chuck by the end effector.

[0025] The focusing ring is positioned by the positioning structure to align the measuring device.

[0026] The offset of the focusing ring is measured by the sensor.

[0027] Optionally, the focusing ring alignment measurement method further includes:

[0028] When placing the wafer to be processed on the electrostatic chuck, the offset of the wafer to be processed is adjusted according to the offset of the focusing ring so that the wafer to be processed is placed concentrically with the focusing ring.

[0029] Optionally, the focusing ring alignment measurement method further includes:

[0030] The position of the focusing ring is adjusted according to the offset of the focusing ring so that the focusing ring is placed concentrically with the center of the electrostatic chuck.

[0031] A plasma processing apparatus, characterized in that it includes a focusing ring alignment measuring device as described above.

[0032] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0033] The focusing ring alignment measuring device provided by this invention uses a positioning structure to achieve positioning between the focusing ring and the electrostatic chuck. A sensor emits a signal to the inner side of the focusing ring, and the offset of the focusing ring relative to the center of the electrostatic chuck is measured through signal feedback from multiple positions on the inner side of the focusing ring. It can be used to measure alignment in the presence of an open cavity or in the absence of an open cavity, which can effectively improve work efficiency and reduce manpower and costs. At the same time, compared with the feeler gauge estimation method, the measurement accuracy of this invention is higher.

[0034] The focusing ring alignment measurement system, method, and plasma processing device provided by this invention belong to the same inventive concept as the focusing ring alignment measurement device and have at least the same beneficial effects, which will not be described in detail here. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram showing a wafer to be processed placed in an electrostatic chuck in a plasma device;

[0037] Figure 2 This is a schematic diagram of the gap between the electrostatic chuck and the focusing ring;

[0038] Figure 3 This is a diagram illustrating the usage state of a focusing ring alignment measuring device according to an embodiment of the present invention.

[0039] Figure 4 This is a front view of a focusing ring alignment measuring device provided in an embodiment of the present invention. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0041] The plasma processing device includes a processing chamber, a base located at the bottom of the processing chamber, and an electrostatic chuck 105 located on the base for supporting and adsorbing the wafer to be processed. Figure 1 A schematic diagram showing the wafer to be processed placed on the electrostatic chuck 105 in the plasma device, as shown. Figure 1As shown, the focusing ring 103 surrounds the base 102 and the wafer 101 to be processed. The wafer 101 to be processed is placed concentrically with the base 102. In order to ensure the uniformity of the etching process in the edge region and the center region of the wafer, the focusing ring 103 should be placed concentrically with the wafer 101 to be processed. Therefore, when installing the focusing ring 103, the centering of the focusing ring 103 with the base 102 should be ensured, that is, the centering of the focusing ring 103 with the wafer 101 to be processed should be ensured.

[0042] Figure 2 This is a schematic diagram of the gap between the electrostatic chuck 105 and the focusing ring, as shown below. Figure 2 As shown, a gap 104 exists between the focusing ring 103 and the base 102. As described in the background section, this gap 104 is crucial for the uniformity and tiling of the etching process. Therefore, it is necessary to ensure that this gap 104 is approximately the same in all directions, i.e., to ensure that the focusing ring 103 is not offset relative to the center of the base 102. Thus, when replacing the focusing ring 103 by opening a cavity, a feeler gauge can be used to estimate whether the gap 104 is the same in all directions, thereby inferring whether the focusing ring 103 is offset relative to the center of the base 102 (i.e., the alignment of the focusing ring 103 with the base 102). However, when replacing the focusing ring 103 without opening a cavity, it is impossible to use a feeler gauge to measure the alignment of the focusing ring 103 with the base 102, which poses a risk to etching uniformity.

[0043] In view of this, the present invention provides a focusing ring alignment measuring device, which is suitable for measuring the offset of the focusing ring relative to the center of the electrostatic chuck 105 after replacing the focusing ring without opening a cavity, so as to facilitate subsequent adjustment of the focusing ring or the wafer to be processed, thereby improving the defect of reduced etching performance caused by the offset of the focusing ring.

[0044] Figure 3 The diagram illustrates the usage state of a focusing ring alignment measuring device according to an embodiment of the present invention, such as... Figure 3 When the focusing ring 103 is replaced, the focusing ring alignment measuring device 200 is placed on the electrostatic chuck 105 of the base 102 to measure the offset of the focusing ring 103 relative to the center of the base 102 (i.e., the center of the electrostatic chuck 105). After the measurement is completed, the focusing ring alignment measuring device 200 is removed from the processing cavity so that the wafer to be processed can be transferred in for etching.

[0045] Figure 4 A schematic diagram illustrates the front view of a focusing ring alignment measuring device provided in an embodiment of the present invention, in conjunction with... Figure 3 and 4As shown, the focusing ring alignment measuring device 200 includes a plate-shaped body 201, a positioning structure 202, and a sensor 203. The positioning structure 202 is disposed on the plate-shaped body 201, and the sensor 203 is also disposed on the plate-shaped body 201, for transmitting signals to the inner surface of the focusing ring 103. During measurement, the plate-shaped body 201 is placed on the electrostatic chuck 105 of the base 102. The positioning structure 202 achieves positioning between the plate-shaped body 201 and the electrostatic chuck 105. The offset of the focusing ring 103 relative to the center of the electrostatic chuck 105 is measured by signal feedback from multiple positions on the inner surface of the focusing ring 103.

[0046] The focusing ring alignment measuring device 200 of the present invention achieves positioning with the electrostatic chuck 105 through the positioning structure 201, and measures the offset of the focusing ring 103 relative to the center of the electrostatic chuck 105 through the sensor 203. It can be used to measure alignment in the case of an open cavity or in the case of no open cavity, which can effectively improve work efficiency and reduce manpower and costs. At the same time, compared with the feeler gauge estimation method, the measurement accuracy of the present invention is higher.

[0047] In this embodiment, the plate-shaped body 201 can be circular, with the same shape as the wafer to be processed. Of course, it can also be set to other shapes; this invention does not limit this. During measurement, the end effector used for wafer transfer in the plasma processing device can transfer the focusing ring aligned with the measuring device 200 to the electrostatic chuck 105, and the positioning structure 202 achieves positioning between the plate-shaped body 201 and the electrostatic chuck 105. It is understood that the plasma etching system has a positioning part for positioning the wafer. Therefore, the positioning structure 201 can be designed to match the positioning part for positioning the wafer in the etching system. The positioning structure 202 can be set with reference to the positioning structure on the wafer to enable the end effector to recognize the positioning structure. Then, according to the program settings, the focusing ring aligned with the measuring device 200 is accurately placed concentrically on the electrostatic chuck 105 of the base 102. Further details are omitted here. In this embodiment, the positioning part of the positioning wafer in the system is used to position the focusing ring alignment measurement device 200. On the one hand, this reduces the design cost of the focusing ring alignment measurement device 200, and on the other hand, the use of the same positioning reference can improve the accuracy of the measurement.

[0048] In this embodiment, the number of sensors 203 can be set to at least three. In other embodiments, four sensors 203 can also be set evenly around the edge of the plate-shaped body 201. In this embodiment, the sensors 203 are evenly spaced around the circumference of the plate-shaped body 201, and at least three sensors 203 emit signals to the inner surface of the focusing ring 103. The offset of the focusing ring 103 relative to the center of the electrostatic chuck 105 is measured by the signal feedback from at least three positions on the inner surface of the focusing ring 103. The distances of each sensor 203 relative to the center of the plate-shaped body 201 can be the same or different, and the present invention does not limit this. Figure 4 As shown, there are three sensors 203, which are disposed on the edge of the plate-shaped body 201 and evenly spaced circumferentially. In some other embodiments, the three sensors 203 are not evenly disposed on the edge. As long as the positions of the inner side of the focusing ring detected by the sensors are not the same, the offset can be determined based on the feedback data and the position of the sensors. It can be understood that the sensors 203 can be disposed above the edge of the plate-shaped body 201, or the thickness of the plate-shaped body 201 can be set to a suitable thickness, and the sensors 203 can be disposed inside the edge of the plate-shaped body 201. Both methods are feasible, as long as the sensor probe is aligned with the inner wall of the focusing ring.

[0049] Furthermore, the sensor 203 is used to measure the distance between the focusing ring alignment device 200 and the focusing ring 103, so as to determine the offset of the focusing ring 103 based on the measurement results of at least three sensors 203. Optionally, the sensor 203 is a laser image sensor or a distance sensor. The offset of the focusing ring 103 can be calculated by comparing the measurement data of each sensor 203. The specific calculation method is as follows: First, the distance value is converted according to the optical path difference or light intensity difference, or the relative distance value is calculated by comparing the light intensity in different directions. Then, since the positions of all sensors 203 are located on the circumference of a circle concentric with the electrostatic chuck 105, the center of the electrostatic chuck 105 is easily determined. The position of the circle formed by the inner surface of the focusing ring 103 can be determined according to the distance value or relative distance value, thereby determining the center of the focusing ring 103. Finally, it can be seen that the vector from the center of the electrostatic chuck 105 to the center of the focusing ring 103 is the offset of the focusing ring 103, that is, the direction and magnitude of the offset of the focusing ring 103 relative to the center of the electrostatic chuck 105 are obtained.

[0050] In other embodiments, the focusing ring alignment measuring device 200 may include only one sensor 203, which is located at the center of the plate-shaped body 201. The sensor 203 can emit signals in multiple directions, and each signal is reflected back to the sensor 203 by different positions on the inner surface of the focusing ring 103, thereby measuring the offset of the focusing ring 103 relative to the center of the base 102. The calculation method is as follows: the position of the sensor 203 is the center of the electrostatic chuck 105. By converting the optical path difference or light intensity difference into a distance value, the distance between the sensor 203 and multiple positions on the inner surface of the focusing ring 103 can be obtained. This allows determination of the position of the circle formed by the inner surface of the focusing ring 103, thus determining the center of the focusing ring 103. Finally, the vector from the center of the electrostatic chuck 105 to the center of the focusing ring 103 is the offset of the focusing ring 103, i.e., the direction and magnitude of the offset of the focusing ring 103 relative to the center of the electrostatic chuck 105.

[0051] Based on the above-described focusing ring alignment measurement device, another embodiment of the present invention provides a focusing ring alignment measurement system, including the above-described focusing ring alignment measurement device, and further including: a communicator and a processor; the communicator is disposed on the plate-shaped main body, and the processor is disposed outside the cavity of the plasma processing device; the communicator is communicatively connected to the sensor and the processor, and is used to wirelessly transmit the measurement results of the sensor to the processor; the processor is used to determine the offset of the focusing ring based on the measurement results.

[0052] Therefore, by means of a communicator mounted on the plate-shaped body, the measurement data of each sensor can be transmitted to a processor outside the plasma processing device cavity, where the processor analyzes and calculates the offset of the focusing ring relative to the center of the base.

[0053] Furthermore, the focusing ring alignment measurement system also includes a display, communicatively connected to the processor, for displaying the measurement results of the sensors and / or the offset of the focusing ring. The display is located outside the cavity. That is, the display can directly display the distance data measured by each sensor received by the processor, or it can display the offset data calculated by the processor, so that technicians can check the alignment of the focusing ring and the electrostatic chuck within the plasma processing device's processing cavity.

[0054] Based on the same inventive concept, another embodiment of the present invention provides a plasma processing apparatus, including the focusing ring alignment measurement system as described above.

[0055] The plasma processing device can be an inductively coupled plasma processing device (ICP), a capacitively coupled plasma processing device (CCP), or other types of plasma processing devices; the present invention does not limit this.

[0056] Based on the same inventive concept, another embodiment of the present invention provides a focusing ring alignment measurement method, comprising the following steps:

[0057] S1, the focusing ring is aligned with the measuring device and placed on the electrostatic chuck by the end effector;

[0058] S2, The focusing ring is positioned by the positioning structure to align the measuring device;

[0059] S3, the offset of the focusing ring is measured by the sensor.

[0060] After measuring the offset of the focusing ring, the offset can be used for feedback control. In one implementation, when placing the wafer to be processed onto the electrostatic chuck, the offset of the wafer to be processed can be adjusted according to the offset of the focusing ring to ensure that the wafer to be processed is placed concentrically with the focusing ring. That is, if the focusing ring has an offset x in a certain direction, the subsequent wafers to be processed are controlled to also be offset by a corresponding offset x in that direction, thereby ensuring that the wafers to be processed are placed concentrically with the focusing ring and eliminating the adverse effects of poor alignment between the focusing ring and the base.

[0061] In another implementation, the end effector can remove the focusing ring and readjust its position according to the offset, repeating this process multiple times until the focusing ring has no offset relative to the center of the electrostatic chuck, or the offset is within an acceptable range. Alternatively, a calibration module can be provided to directly adjust the focusing ring according to the offset, ensuring that the focusing ring has no offset relative to the center of the electrostatic chuck, or the offset is within an acceptable range.

[0062] The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to each other.

[0063] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or field device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or field device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or field device that includes said element.

[0064] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A focusing ring alignment measuring device for a plasma processing apparatus, the plasma processing apparatus comprising a reaction chamber and an electrostatic chuck located within the reaction chamber, characterized in that, include: plate-like body; A positioning structure is provided on the plate-shaped main body; The positioning structure matches the positioning part for positioning wafers provided on the electrostatic chuck, so that the center of the plate-shaped body is aligned with the center of the electrostatic chuck; A sensor, disposed on the upper surface or side of the plate-shaped body, is used to emit light signals toward the inner side of the focusing ring; During measurement, the plate-shaped body is placed on the electrostatic chuck, and the positioning structure is used to position the plate-shaped body relative to the center of the electrostatic chuck. The offset of the focusing ring relative to the center of the electrostatic chuck is measured by optical signal feedback from multiple positions on the inner side of the focusing ring.

2. The focusing ring alignment measuring device as described in claim 1, characterized in that, The number of sensors is at least three, and they are evenly or non-uniformly spaced along the circumference of the plate-shaped body.

3. The focusing ring alignment measuring device as described in claim 2, characterized in that, The sensor is used to measure the distance between the focusing ring alignment measuring device and the focusing ring, so as to determine the offset of the focusing ring based on the measurement results of at least three of the sensors.

4. The focusing ring alignment measuring device as described in claim 2, characterized in that, The sensor is a laser image sensor or a distance sensor.

5. A focusing ring alignment measurement system, characterized in that, The focusing ring alignment measuring device as described in any one of claims 1-4 further includes: a communicator and a processor; The communicator is disposed on the plate-shaped main body, and the processor is disposed outside the cavity of the plasma processing device. The communicator is communicatively connected to the sensor and the processor and is used to transmit the measurement results of the sensor to the processor. The processor is used to determine the offset of the focusing ring based on the measurement results.

6. The focusing ring alignment measurement system as described in claim 5, characterized in that, It also includes a display, which is communicatively connected to the processor, for displaying the measurement results of the sensor and / or the offset of the focusing ring, the display being located outside the cavity.

7. A method for aligning and measuring a focusing ring, characterized in that, include: The focusing ring alignment measuring device as described in any one of claims 1-4 is placed on the electrostatic chuck by an end effector; The focusing ring is positioned by the positioning structure to align the measuring device. The offset of the focusing ring is measured by the sensor.

8. The focusing ring alignment measurement method as described in claim 7, characterized in that, Also includes: When placing the wafer to be processed on the electrostatic chuck, the offset of the wafer to be processed is adjusted according to the offset of the focusing ring so that the wafer to be processed is placed concentrically with the focusing ring.

9. The focusing ring alignment measurement method as described in claim 7, characterized in that, Also includes: The position of the focusing ring is adjusted according to the offset of the focusing ring so that the focusing ring is placed concentrically with the center of the electrostatic chuck.

10. A plasma processing apparatus, characterized in that, Includes the focusing ring alignment measurement system as described in claim 5 or 6.

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