Optical measurement apparatus for measuring thickness of deposited film layer, and furnace tube device and control method

Abstract

Provided in the present application are an optical measurement apparatus for measuring the thickness of a deposited film layer, and a furnace tube device and a control method. The optical measurement apparatus comprises a light source, a light sensing unit and an intra-cavity thin tube, wherein the intra-cavity thin tube is arranged in a furnace tube device, the top end of the intra-cavity thin tube is a light transmissive and reflective plane, the material of the light transmissive and reflective plane has a first optical parameter, a deposited film layer has a second optical parameter, and the first optical parameter is different from the second optical parameter; the light source is used for providing, to the inside of the intra-cavity thin tube, incident light which is parallel to the axial direction of the intra-cavity thin tube; the light sensing unit is used for receiving reflected light reflected from the light transmissive and reflective plane of the intra-cavity thin tube; and the optical measurement apparatus is configured to obtain, according to the reflected light, the thickness of a film layer deposited on the light transmissive and reflective plane. The present application can accurately obtain the thickness of a film layer in a timely manner without relying on temperature measurement, and control a dry method cleaning reaction end point.

Description

Optical detection device, furnace tube equipment and control method for detecting thickness of deposited film Technical Field

[0001] The present application mainly relates to the field of semiconductor technology, and in particular to an optical detection device for detecting the thickness of a deposited film layer, a furnace tube device, and a method for controlling the cleaning endpoint of the furnace tube device. Background Art

[0002] At present, in semiconductor-related processes, the deposition of silicon thin films is mainly achieved by decomposing silane (SiH4) into silicon atoms under heat in a high-temperature furnace tube and then aggregating them to obtain high-purity silicon thin films. As the number of times the furnace tube equipment is used increases, a thicker silicon layer will be deposited on the cavity and the inner surface of the vacuum pipe close to the cavity. Continuing to use such equipment is prone to problems such as unstable silicon film thickness control and particle contamination. Therefore, after the silicon film layer accumulates to a certain thickness, the furnace tube equipment needs to perform wet / dry cleaning on the working chamber. Generally, wet cleaning requires the removal of relevant components of the furnace body, and dry cleaning can remove the silicon layer through in-situ high-temperature reaction of special gases. The dry etching reaction is highly active, and the by-products can be removed after high-temperature reaction by directly introducing special gases into the cavity.

[0003] During the dry etching cleaning process, special gases (typically Cl2, F2, ClF3, etc.) can also chemically react with the SiO2 on the quartz wall surface within the furnace tube, damaging the quartz wall surface or reducing the surface molecular polarity, which is not conducive to the adhesion of the film. When the film is not firmly attached, it is easy to fall off during the process, forming contaminant particles. Therefore, in the dry etching cleaning process, determining the endpoint of the dry etching is very important. That is, it is necessary to remove the silicon layer while avoiding excessive reaction of the quartz wall.

[0004] In high-temperature CVD furnace deposition equipment, the special gas used for dry cleaning releases heat when it reacts with the silicon layer. Usually, the endpoint of the dry etching of the silicon layer can be controlled by setting a temperature fluctuation value (±1°C, ±0.5°C, etc.) based on the temperature change process displayed by the thermocouple inside the chamber. When the temperature inside the furnace reaches this range, the inlet valve of the special gas pipeline is immediately closed to avoid excessive etching. However, the current method of using thermocouples to detect temperature changes to control the endpoint of dry cleaning has the following problems:

[0005] (1) For the thermal effect in special gas reactions, the furnace temperature control has a certain delay;

[0006] (2) For temperature-controlled thermocouples at different positions and heights, the thickness of the silicon film on the surface of the thermocouple sleeve may vary greatly. Silicon layers of different thicknesses have different effects on heat conduction, which will interfere with and reduce the accuracy of heat detection;

[0007] (3) The temperature needs to be kept stable for a certain period of time as a limiting condition. This process may corrode the quartz wall of the furnace tube, affecting the life of the furnace tube equipment and the process indicators during use.

[0008] Summary of the Invention

[0009] The technical problem to be solved by the present application is to provide an optical detection device that is independent of temperature detection and can obtain the film thickness in a timely and accurate manner to control the end point of the dry cleaning reaction, a furnace tube device using the optical detection device, and a method for controlling the cleaning end point of the furnace tube device.

[0010] In order to solve the above technical problems, the present application provides an optical detection device for detecting the thickness of a deposited film layer, comprising a light source, a light sensing unit and an intracavitary capillary, wherein the intracavitary capillary is arranged in a furnace tube device, the top end of the intracavitary capillary is a light-transmitting reflective plane, the material of the light-transmitting reflective plane has a first optical parameter, the deposited film layer has a second optical parameter, and the first optical parameter is different from the second optical parameter; the light source is used to provide incident light parallel to the axis of the intracavitary capillary to the interior of the intracavitary capillary; the light sensing unit is used to receive reflected light reflected from the light-transmitting reflective plane of the intracavitary capillary; the optical detection device is configured to: obtain the thickness of the film layer deposited on the light-transmitting reflective plane based on the reflected light.

[0011] In one embodiment of the present application, the light-transmitting and light-reflecting surface is made of quartz.

[0012] In one embodiment of the present application, the material of the intracavitary tube is quartz.

[0013] In one embodiment of the present application, the first optical parameter includes the refractive index of the light-transmitting and light-reflecting plane to the incident light, and the second optical parameter includes the refractive index of the deposited film layer to the incident light.

[0014] In one embodiment of the present application, the first optical parameter further includes an extinction coefficient of the light-transmitting and reflective plane to the incident light, and the second optical parameter further includes an extinction coefficient of the deposited film layer to the incident light.

[0015] In one embodiment of the present application, the inner diameter of the intraluminal tube ranges from 0 to 100 mm.

[0016] In one embodiment of the present application, the inner diameter of the intraluminal tube is in the range of 5-15 mm.

[0017] In one embodiment of the present application, the inner diameter of the intraluminal tube is in the range of 2-10 mm.

[0018] In one embodiment of the present application, the wall thickness of the intraluminal tube is in the range of 0.2-3 mm.

[0019] In one embodiment of the present application, the light source is used to provide light waves with wavelengths ranging from visible light to near-infrared light.

[0020] In one embodiment of the present application, the light source and the light sensing unit are arranged outside the furnace tube device.

[0021] In one embodiment of the present application, an optical module is further included, which is arranged between the light source and the intracavitary tube and is used to adjust the light wave emitted by the light source to obtain the incident light.

[0022] In one embodiment of the present application, a light-passing pipe is further included, which is arranged between the optical module and the intracavitary capillary. The light-passing pipe and the intracavitary capillary are connected to each other through a bent connection portion, and a dimming device is provided in the bent connection portion. The dimming device is used to reflect the incident light, and make the reflected incident light propagate inside the intracavitary capillary along an axial direction parallel to the axial direction of the intracavitary capillary and reach the light-transmitting and reflective plane. In addition, the dimming device is also used to reflect the reflected light, and make the reflected light propagate in the light-passing pipe along an axial direction parallel to the axial direction of the light-passing pipe and be received by the light sensing unit.

[0023] In one embodiment of the present application, the height of the intracavity thin tube is smaller than the height of the internal cavity of the furnace tube device.

[0024] In one embodiment of the present application, the optical detection device is further configured to obtain the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the intensity of the reflected light.

[0025] In order to solve the above technical problems, the present application also proposes a furnace tube device, including a heating outer sleeve, which is connected to the optical detection device as described above, wherein the intracavitary capillary is arranged in the heating outer sleeve, and the intracavitary capillary is arranged parallel to the heating outer sleeve.

[0026] In one embodiment of the present application, the heating outer sleeve further includes an inner lining tube. When semiconductor thin film deposition is performed, the wafer is arranged inside the inner lining tube, wherein the intracavitary capillary is arranged in the outer space of the inner lining tube.

[0027] In order to solve the above-mentioned technical problems, the present application also proposes a method for controlling the cleaning end point of furnace tube equipment, comprising: in the dry cleaning process of the furnace tube equipment, using the optical detection device as described above to detect the thickness of the film layer on the light-transmitting and reflective plane; when the thickness of the film layer reaches a preset value, stopping the dry cleaning process of the furnace tube equipment.

[0028] The optical detection device of the present application uses an intracavitary capillary tube to detect the thickness of a deposited film layer. The translucent reflective plane at the top of the intracavitary capillary tube has a first optical parameter different from that of the deposited film layer. Therefore, the light reflected by the translucent reflective plane can reflect the thickness of the film layer deposited on the translucent reflective plane, thereby further reflecting the thickness of the deposited film layer inside the furnace tube device. The optical detection device of the present application does not rely on a temperature detection device and is not affected by temperature, thus avoiding the problems encountered when using thermocouples to detect temperature changes to control the endpoint of dry cleaning. At the same time, due to the high transmission speed of the optical signal, the furnace tube heating process has very little interference with the optical signal, so the film thickness can be quickly and accurately obtained, thereby achieving effective monitoring of the dry cleaning endpoint.

[0029] Summary of the Figures

[0030] The features and properties of the present invention are further described by the following examples and accompanying drawings.

[0031] FIG1 is a schematic structural diagram of an optical detection device according to an embodiment of the present application;

[0032] FIG2 is a schematic structural diagram of an optical detection device according to another embodiment of the present application;

[0033] 3 is a schematic diagram of a curve showing the relationship between silicon film thickness and reflected light intensity obtained by performing optical simulation based on the principle of a light detection device according to an embodiment of the present application;

[0034] FIG4 is a schematic diagram of a furnace tube device according to an embodiment of the present application;

[0035] FIG5 is an exemplary flow chart of a method for controlling a cleaning endpoint of a furnace tube device according to an embodiment of the present application.

[0036] Preferred embodiments of the present invention

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0038] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0039] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0040] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0041] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0042] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0043] The optical detection device for detecting the thickness of deposited films disclosed herein can be used to detect the thickness of deposited films involved in any semiconductor manufacturing process. In particular, it can be used to perform real-time film thickness detection during the dry cleaning process of furnace tube equipment, thereby assisting in determining and controlling the endpoint of the dry cleaning reaction and preventing overreaction or underreaction.

[0044] Figure 1 is a schematic diagram of the structure of an optical detection device for detecting the thickness of a deposited film layer according to one embodiment of the present application. Referring to Figure 1 , optical detection device 100 of this embodiment includes a light source 110, a light sensing unit 120, and an intracavitary capillary tube 130. In particular, intracavitary capillary tube 130 is disposed within a furnace tube apparatus 101. The top of intracavitary capillary tube 130 is a light-transmitting, reflective surface 131, as shown in the enlarged schematic diagram of section A in Figure 1 . The material of light-transmitting, reflective surface 131 has first optical parameters, and the deposited film layer has second optical parameters, where the first optical parameters are different from the second optical parameters.

[0045] As shown in Figure 1, the inner diameter of the intracavitary capillary 130 is relatively thin compared to the size of the furnace tube device 101. In some embodiments, the inner diameter of the intracavitary capillary 130 ranges from 0 to 100 mm, such as 2 mm, 5 mm, 10 mm, 15 mm, 20 mm, 50 mm, 75 mm, 100 mm, etc. When the inner diameter of the intracavitary capillary 130 is 0 mm, it means that the capillary is solid and made of a light-transmitting material, and the light emitted by the light source 110 can propagate within the intracavitary capillary 130. Preferably, the inner diameter ranges from 5 to 15 mm. In some embodiments, the inner diameter ranges from 2 to 10 mm. Using a relatively thin intracavitary capillary 130 can reduce the impact on the process within the furnace. If the size of the intracavitary capillary 130 is large, it will affect the airflow inside the furnace tube device 101, thereby affecting the uniformity of processes such as thin film deposition and etching, and there are also safety issues.

[0046] As shown in Figure 1, the intracavitary capillary tube 130 is a straight tube rather than a curved tube. Specifically, when arranged inside the furnace tube device 101, the axial direction of the intracavitary capillary tube 130 is parallel to the axial direction of the furnace tube. That is to say, if the axial direction of the furnace tube is vertical, the axial direction of the intracavitary capillary tube 130 is also vertical; if the axial direction of the furnace tube is horizontal, the axial direction of the intracavitary capillary tube 130 is also horizontal. It should be noted that when the axial direction of the furnace tube is vertical, the surface of the wafer is arranged parallel to the horizontal direction, and when the axial direction of the furnace tube is horizontal, the surface of the wafer is arranged parallel to the vertical direction.

[0047] As shown in Figure 1, in this embodiment, the intracavitary capillary 130 can be a circular tube, and the cross-sectional shape of the light-transmitting reflective plane 131 is circular. In other embodiments, the intracavitary capillary 130 can be a square tube, an irregularly shaped tube, etc., and the cross-sectional shape of the light-transmitting reflective plane 131 can be a rectangle, an irregular shape, etc. The light-transmitting reflective plane 131 is a smooth plane. Combined with the description in the previous paragraph, the light-transmitting reflective plane 131 is parallel to the surface of the wafer. Therefore, during the thin film deposition process, the thickness of the thin film deposited on the light-transmitting reflective plane 131 is almost equal to the thickness of the thin film on the inner wall of the furnace tube. Therefore, the thickness of the thin film on the light-transmitting reflective plane 131 can reflect the thickness of the thin film on the inner wall of the furnace tube. It should be noted that the film thickness on the inner wall of the furnace tube and the upper surface of the wafer are not strictly equal, and generally there is a small difference of ±1nm.

[0048] In some embodiments, the wall thickness of the intraluminal capillary tube 130 ranges from 0.2 to 3 mm, and similarly, the thickness of the light-transmitting and reflective surface 131 also ranges from 0.2 to 3 mm. For example, the thickness can be 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, etc. The wall of the intraluminal capillary tube 130 and the light-transmitting and reflective surface 131 at the top can be integrally formed.

[0049] The first optical parameter and the second optical parameter mentioned above refer to the optical properties exhibited when light is irradiated onto the light-transmitting and reflective plane 131 and the deposited film layer, such as reflectivity, refractive index, transmittance, etc.

[0050] It should be noted that, for the same light, the first optical parameter is different from the second optical parameter.

[0051] In some embodiments, the first optical parameter includes the refractive index of the light-transmitting and light-reflecting plane 131 to the incident light, and the second optical parameter includes the refractive index of the deposited film layer to the incident light, and the first optical parameter and the second optical parameter are different.

[0052] The inventors of the present application have discovered through experiments that the optical properties of silicon and silicon dioxide are quite different. When the incident light is a light wave in the range of visible light to near-infrared light, the refractive index range of silicon is 3.5-6.1, and the refractive index range of silicon dioxide is 1.46-1.48. For some embodiments, the material of the light-transmitting reflective plane 131 is quartz, and the deposited film layer is a silicon thin film. When the thickness of the silicon thin film deposited on the light-transmitting reflective plane 131 increases from 0 to 5 nm, the optical reflectivity will change significantly. One embodiment of the present application uses quartz to form the light-transmitting reflective plane 131, which can be used to detect the thickness of the silicon thin film. Based on this discovery, when depositing film layers of other materials, other materials with optical parameters that are significantly different from those of the deposited film layer can be selected as the material of the light-transmitting reflective plane 131, so that the thickness of the film layer can also be detected based on the changes in the detected optical parameters.

[0053] In some embodiments, only the light-transmitting and light-reflecting surface 131 of the intraluminal tube 130 is made of quartz, and the other parts can be made of other materials.

[0054] In some embodiments, the entire material of the intracavitary capillary 130 is quartz, that is, it is a quartz capillary.

[0055] In some embodiments, the first optical parameter also includes the extinction coefficient of incident light on the light-transmitting and reflective surface 131, and the second optical parameter also includes the extinction coefficient of the deposited film layer. For example, the extinction coefficient of silicon ranges from 0 to 0.75, while the extinction coefficient of silicon dioxide is 0, a significant difference between the two. Combined with the difference in refractive index between the two materials, when the thickness of the silicon film deposited on the light-transmitting and reflective surface 131 increases from 0 to 5 nm, the optical reflectivity changes significantly.

[0056] As shown in FIG1 , the light source 110 and the light sensing unit 120 are both disposed outside the furnace tube apparatus 101. Of course, if both the light source 110 and the light sensing unit 120 are high-temperature resistant, they can also be disposed inside the furnace tube apparatus 101 or in a low-temperature chamber within the furnace tube apparatus 101, and this application does not impose any restrictions thereto.

[0057] As shown in Figure 1, the light source 110 is used to provide incident light parallel to the axis of the intracavitary tube 130 to the inside of the intracavitary tube 130. The present application does not limit the connection method between the light source 110 and the intracavitary tube 130, as long as parallel incident light can be provided to the inside of the intracavitary tube 130. According to such a setting, parallel light is transmitted in the intracavitary tube 130 and directly reaches the light-transmitting reflective plane 131. Part of the incident light passes through the light-transmitting reflective plane 131, and another part is reflected back by the light-transmitting reflective plane 131, thereby forming reflected light. When the thickness of the thin film deposited on the light-transmitting reflective plane 131 changes, it will affect the properties of the reflected light. The light sensing unit 120 is used to receive the reflected light reflected back from the light-transmitting reflective plane 131 of the intracavitary tube 130. Since the parallel light propagating in the intracavitary tube 130 is not easily dispersed, it is beneficial to obtain information of sufficient accuracy therefrom, which is beneficial to improve the accuracy of judging the thickness of the film layer.

[0058] In some embodiments, the light source 110 and the light sensing unit 120 may be independently provided or integrally provided.

[0059] In some embodiments, the light source 110 is configured to provide light waves with wavelengths ranging from visible light to near infrared light.

[0060] In some embodiments, an independent controller can obtain the thickness of the film deposited on the light-transmitting and reflective plane 131 based on the reflected light, thereby obtaining the thickness of the film on the inner wall of the furnace tube, thereby further determining and controlling the end point of the dry cleaning process.

[0061] In some embodiments, the controller may be integrated with the light source 110 and the light sensing unit 120 .

[0062] The optical detection device of this application replaces the conventional process control method of measuring temperature changes with thermocouples, thus avoiding the various problems associated with thermocouple use. Furthermore, due to the high transmission speed of optical signals, the furnace heating process minimally interferes with the optical signal, enabling rapid and accurate determination of film thickness, thereby effectively monitoring the endpoint of dry cleaning.

[0063] FIG2 is a schematic structural diagram of an optical detection device according to another embodiment of the present application. Referring to FIG2 , the optical detection device 200 of this embodiment, in addition to the light source 110, the light sensing unit 120 and the intracavitary capillary 130, further includes an optical module 210, which is arranged between the light source 110 and the intracavitary capillary 130, and is used to adjust the light wave emitted by the light source 110 to obtain incident light parallel to the axial direction of the intracavitary capillary. The optical module 210 may include optical instruments such as a flat mirror, a convex lens, and a concave lens. According to this embodiment, the light source 110 may be a point light source, and by arranging a combination of various lenses in the optical module 210, the light wave emitted by the light source 110 can be adjusted so that the incident light entering the intracavitary capillary 130 is parallel light parallel to the axial direction of the intracavitary capillary. FIG2 is for reference only. According to this embodiment, it is conceivable that the light source 110 and the optical module 210 can be disposed directly below the intracavitary capillary 130 so that the parallel light emitted from the optical module 210 directly enters the intracavitary capillary 130 .

[0064] Furthermore, referring to FIG2 , the optical detection device 200 further includes a light passage 220 disposed between the optical module 210 and the intracavitary capillary 130. The light passage 220 and the intracavitary capillary 130 are interconnected via a bent connection portion 230, wherein a dimming device 231 is provided in the bent connection portion 230. The dimming device 231 is configured to reflect incident light and cause the reflected incident light to propagate within the intracavitary capillary 130 along an axis parallel to the axis of the intracavitary capillary and reach the light-transmitting and reflecting plane 131. Furthermore, the dimming device 231 is configured to reflect light reflected from the light-transmitting and reflecting plane 131 and cause the reflected light to propagate within the light passage 220 along an axis parallel to the axis of the light passage and be received by the light sensing unit 120.

[0065] In some embodiments, the bent connection portion 230 is a metal joint having a right-angle bent structure.

[0066] As shown in Figure 2, the light pipe 220 and the intracavitary capillary 130 are perpendicularly connected to each other through the bent connection portion 230, that is, the axial angle between the two is 90 degrees. In other embodiments, the angle can also be other angles, and this application does not limit this.

[0067] As shown in Figure 2, in some embodiments, the dimming device 231 is a reflector. When the angle between the light pipe 220 and the intracavitary capillary 130 is 90 degrees, the dimming device 231 forms a 45-degree angle with both the axis of the light pipe and the axis of the intracavitary capillary, respectively. This allows the collimated light in the light pipe 220 to be reflected as parallel light parallel to the axis of the intracavitary capillary. It will be appreciated that when this angle is not 90 degrees, the direction of light propagation can be controlled by adjusting the angle of the reflector or increasing the number of reflectors.

[0068] As shown in FIG2 , in this embodiment, the optical module 210 can be disposed in the light pipe 220, for example, near an outward-facing exit, to adjust the light waves entering the light pipe 220. In some embodiments, the optical module 210 can also include a filter to adjust the wavelength of the light waves to an appropriate wavelength based on actual sensing accuracy requirements.

[0069] As shown in FIG. 2 , in this embodiment, the locations of the power source 110 and the light sensing unit 120 are both related to the location of the light pipe 220 .

[0070] In some embodiments, the optical module 210 may be disposed only in the propagation path of the incident light, and the reflected light no longer passes through the optical module 210 .

[0071] In some embodiments, in order to achieve synchronous measurement of light, the dimming device 231 is a 45-degree inclined half-mirror, so that the incident light can enter the intracavitary tube 130 after being reflected by the half-mirror, and the reflected light after passing through the transparent and reflective plane 131 can pass directly, thereby achieving the measurement of reflected light while emitting light.

[0072] 2 , in some embodiments, the optical detection device 200 further includes a connector 240 for fixing the intracavitary tube 130 to the bent connection portion 230 . A sealing device 250 may also be included for sealing the connection between the bent connection portion 230 and the intracavitary tube 130 .

[0073] In some embodiments, the step of the optical detection device of the present application obtaining the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the reflected light includes: obtaining the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the intensity of the reflected light.

[0074] The inventors of this application have discovered through experiments that light will be weakened to varying degrees after being reflected by silicon films of different thicknesses, and the light intensity reaches its lowest value when the thickness of the silicon film is 0. Figure 3 is a curve showing the relationship between the thickness of the silicon film and the intensity of the reflected light, obtained by optical simulation based on the principle of the light detection device of this application. Referring to Figure 3, the horizontal axis is the thickness of the silicon film (Thickness), in nm, and the vertical axis is the percentage of the reflected light intensity relative to the incident light intensity (Reflectance), in %. The wavelength of the light wave emitted by the light source 110 corresponding to this data is 850nm, which belongs to the near-infrared light range. According to the optical simulation data, when the thickness of the silicon film is between 0-60nm, the reflected light intensity increases with the increase of the thickness of the silicon film. Specifically, referring to Figure 3, relative to the incident light intensity, when the silicon film is 50nm thick, the reflected light intensity is approximately 63% of the incident light intensity; at 10nm and 5nm, the reflected light intensity is only 16% and 7% of the incident light intensity, respectively. Therefore, optical simulation methods can be used to select one or more light waves. The resulting reflected light signal intensity, or the ratio of reflected light intensity to incident light intensity, can be used to store the test results and accurately determine the thickness of the silicon film. Based on these test results, in practical applications, precise conditions can be set to control the silicon film thickness to a certain stage during the dry etching process, where the thickness is relatively thin or just reaches zero.

[0075] The present application does not impose any limitation on the length or height of the intracavitary tube 130 .

[0076] FIG4 is a schematic diagram of a furnace tube device according to an embodiment of the present application. Referring to FIG4 , the furnace tube device 400 includes a heating outer sleeve 410, which is connected to the optical detection device described above in the present application, wherein the intracavitary capillary tube 130 is disposed inside the heating outer sleeve 410, and the intracavitary capillary tube 130 is disposed parallel to the heating outer sleeve 410. FIG4 shows a vertical furnace tube device. If the heating outer sleeve 410 is disposed extending in a vertical direction, then the intracavitary capillary tube 130 also extends in a vertical direction, and the two are parallel to each other. The optical detection device shown in FIG4 is the optical detection device 200 shown in FIG2 , wherein the light source 110 and the light sensing unit 120 are not shown, and it may also be the optical detection device 100 shown in FIG1 .

[0077] In some embodiments, the heating outer sleeve 410 further includes an inner lining tube 420 . When semiconductor thin film deposition is performed, the wafer W is disposed inside the inner lining tube 420 , wherein the intracavitary capillary 130 is disposed in the outer space of the inner lining tube 420 .

[0078] Referring to Figure 4, the process gas GAS can be passed into the chamber from the inside of the inner liner tube 420. There is a vacuum line 430 connected between the inner liner tube 420 and the heating outer sleeve 410, and a vacuum pump PUMP is used to achieve gas extraction. Therefore, the flow of gas in the process is shown by the arrows in Figure 4, that is, it starts from the bottom of the inner liner tube 420 and rises above the inner liner tube 420, then enters the space between the inner liner tube 420 and the heating outer sleeve 410 from the top down, and is finally extracted through the vacuum line 430. In the deposition process under conventional process conditions, if the process parameters such as temperature at different positions are consistent, the relationship between the thickness of the films deposited at different heights P1, P2, and P3 is: Th(P1)>Th(P2)>Th(P3), where Th represents the film thickness. In other words, the higher the height, the thicker the thickness. Among them, the deposition thickness at position P1 is close to the thickness of the film deposited inside the inner liner tube 420.

[0079] Similar to the deposition process, during the dry cleaning of the furnace tube wall, the concentration and flow of the special gas used for the dry etching reaction also follow the same pattern as indicated by the arrows in Figure 4. Therefore, at the higher position P1, the etching reaction targeting the accumulated thin film on the tube wall is completed first, the etching reaction at the middle position P2 is completed slightly later, and the etching reaction at the lower position P3 is completed even later. Although the film thickness and dry cleaning changes at position P1 are similar to those inside the inner tube liner 420, during the furnace tube wall cleaning process, the bottom of the furnace tube and locations with weaker gas diffusion also need to be thoroughly removed. In other words, not only must the thin film on the tube wall inside the inner tube liner 420 be completely removed, but the thin film deposited on the bottom of the external heating outer tube 410 must also be reacted out. Based on the working order of the dry cleaning gas within the furnace tube cavity, only when the thin film at position P2 or P3 is reacted and removed can it be considered that the tube walls of both the inner tube liner 420 and the external heating outer tube 410 have been effectively dry cleaned. With this in mind, the height and length of the intracavitary capillary tube 130 need to be carefully designed. If the translucent reflective surface 131 is too close to the bottom of the furnace tube apparatus 400, while the thin film on the furnace tube wall can be effectively removed, the quartz on the chamber wall may also be etched, resulting in over-etching. If the translucent reflective surface 131 is too high, when the film thickness on the translucent reflective surface 131 reaches the preset thickness, the film thickness on the tube wall at or near the bottom of the furnace tube apparatus 400 is still relatively thick, resulting in insufficient etching. Therefore, the height of the intracavitary capillary tube 130 should be set near position P2, or between positions P2 and P3, to achieve better process results.

[0080] In some embodiments, the height of the intracavitary tube 130 is less than the height of the interior cavity of the furnace tube apparatus 400. The optimal height can be determined based on the actual machine design and related settings. In some embodiments, the height of the intracavitary tube 130 is less than or equal to 2 / 3 of the height of the interior cavity of the furnace tube apparatus 400. The ratio of the height of the intracavitary tube 130 to the interior height of the furnace tube apparatus 400 can be 2 / 3, 1 / 3, 1 / 4, 2 / 5, etc.

[0081] In some embodiments, assuming that the inner height of the furnace tube device 400 is 1500 mm, the height of the intracavitary capillary tube 130 is anywhere between 0 and 1000 mm.

[0082] The furnace tube equipment 400 of the present application has a built-in intracavitary capillary tube 130 in an optical detection device, so that the optical detection device can be used to timely and accurately detect the film thickness of the furnace tube wall, thereby further assisting in determining the end point of dry etching during the dry cleaning process of the furnace tube wall to avoid insufficient etching and excessive etching.

[0083] FIG5 is an exemplary flow chart of a method for controlling the cleaning endpoint of a furnace tube device according to an embodiment of the present application. The furnace tube device in the control method may be the furnace tube device 400 described above. Referring to FIG5 , the method for controlling the cleaning endpoint of the furnace tube device according to the embodiment includes:

[0084] Step S510: In the dry cleaning process of the furnace tube equipment, the optical detection device 100 or 200 of the present application is used to detect the thickness of the film layer on the light-transmitting and light-reflecting plane 131;

[0085] Step S520: When the film thickness reaches a preset value, the dry cleaning process of the furnace tube equipment is stopped.

[0086] The control method can effectively control the end point of the dry cleaning process and avoid insufficient etching and excessive etching.

[0087] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely examples and do not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to the present application. Such modifications, improvements, and revisions are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0088] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0089] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0090] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

Claims

1. An optical detection device for detecting the thickness of a deposited film, characterized in that: It includes a light source, a light sensing unit and an intracavitary capillary, wherein: The intracavity capillary tube is arranged in a furnace tube device, the top end of the intracavity capillary tube is a light-transmitting and light-reflecting plane, the material of the light-transmitting and light-reflecting plane has a first optical parameter, the deposited film layer has a second optical parameter, and the first optical parameter is different from the second optical parameter; The light source is used to provide incident light parallel to the axial direction of the intracavitary capillary into the interior of the intracavitary capillary; The light sensing unit is used to receive the reflected light reflected from the light-transmitting and light-reflecting plane of the intracavitary capillary; The optical detection device is configured to obtain the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the reflected light.

2. The optical detection device according to claim 1, characterized in that: The material of the light-transmitting and light-reflecting plane is quartz.

3. The optical detection device according to claim 1, characterized in that: The material of the intracavitary capillary is quartz.

4. The optical detection device according to claim 1, characterized in that: The first optical parameter includes the refractive index of the light-transmitting and light-reflecting plane to the incident light, and the second optical parameter includes the refractive index of the deposited film layer to the incident light.

5. The optical detection device according to claim 4, characterized in that: The first optical parameter also includes the extinction coefficient of the light-transmitting and light-reflecting plane to the incident light, and the second optical parameter also includes the extinction coefficient of the deposited film layer to the incident light.

6. The optical detection device according to claim 1, characterized in that: The inner diameter of the intracavitary capillary is in the range of 0-100 mm.

7. The optical detection device according to claim 6, characterized in that: The inner diameter of the intracavitary capillary is in the range of 5-15 mm.

8. The optical detection device according to claim 6, characterized in that: The inner diameter of the intracavitary capillary is in the range of 2-10 mm.

9. The optical detection device according to claim 1, characterized in that: The wall thickness of the intracavitary capillary is in the range of 0.2-3 mm.

10. The optical detection device according to claim 1, characterized in that: The light source is used to provide light waves with wavelengths ranging from visible light to near infrared light.

11. The optical detection device according to claim 1, characterized in that: The light source and the light sensing unit are arranged outside the furnace tube device.

12. The optical detection device according to claim 1, characterized in that: It also includes an optical module, which is arranged between the light source and the intracavitary capillary and is used to adjust the light wave emitted by the light source to obtain the incident light.

13. The optical detection device according to claim 12, characterized in that: It also includes a light-passing pipe, which is arranged between the optical module and the intracavitary capillary, the light-passing pipe and the intracavitary capillary are connected to each other through a bending connection part, and a dimming device is provided in the bending connection part, the dimming device is used to reflect the incident light, and make the reflected incident light propagate inside the intracavitary capillary along the axial direction parallel to the intracavitary capillary and reach the light-transmitting and reflective plane, and the dimming device is also used to reflect the reflected light, and make the reflected light propagate in the light-passing pipe along the axial direction parallel to the light-passing pipe and be received by the light sensing unit.

14. The optical detection device according to claim 1, characterized in that: The height of the thin tube in the cavity is smaller than the height of the internal cavity of the furnace tube equipment.

15. The optical detection device according to claim 1, characterized in that: The optical detection device is further configured to obtain the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the light intensity of the reflected light.

16. A furnace tube device, comprising a heating outer sleeve, characterized in that: Connected to the optical detection device according to any one of claims 1 to 15, wherein the intracavitary capillary is arranged in the heating outer sleeve, and the intracavitary capillary is arranged parallel to the heating outer sleeve.

17. The furnace tube equipment according to claim 16, characterized in that: The heating outer sleeve also includes an inner lining tube. When semiconductor thin film deposition is performed, the wafer is arranged inside the inner lining tube, wherein the intracavitary capillary is arranged in the outer space of the inner lining tube.

18. A method for controlling the cleaning endpoint of a furnace tube device, characterized in that: include: In the dry cleaning process of the furnace tube equipment, the thickness of the film layer on the light-transmitting and light-reflecting plane is detected by using the optical detection device as described in any one of claims 1 to 15; When the film thickness reaches a preset value, the dry cleaning process of the furnace tube equipment is stopped.

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