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

Abstract

The invention provides an optical detection device for detecting the thickness of a deposited film layer, furnace tube equipment and a control method. The optical detection device comprises a light source, a light sensing unit and an intracavity thin tube, the intracavity thin tube is arranged in furnace tube equipment, the top end of the intracavity thin 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 and the second optical parameter are different. The first optical parameter is different from the second optical parameter; the light source is used for providing incident light parallel to the axial direction of the intracavity thin tube into the intracavity thin tube; the light sensing unit is used for receiving reflected light reflected back from the light-transmitting and light-reflecting plane of the intracavity thin tube; and the optical detection device is configured to obtain the thickness of a film layer deposited on the light-transmitting and light-reflecting plane according to the reflected light. The method does not depend on temperature detection, and can timely and accurately obtain the thickness of the film layer and control the reaction endpoint of dry cleaning.

Description

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 control method for the cleaning endpoint of the furnace tube device. Background Art

[0002] At present, in semiconductor-related processes, the deposition of silicon thin film is mainly achieved by decomposing silane (SiH4) into silicon atoms under heat in a high-temperature furnace tube and then aggregating them to obtain a high-purity silicon thin film. 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 pipeline close to the cavity. Continuing to use such equipment is prone to problems such as unstable silicon film thickness control and particle contamination. Therefore, the furnace tube equipment needs to perform wet / dry cleaning on the working chamber after the silicon film layer accumulates to a certain thickness. 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 a high-temperature reaction by directly introducing special gases into the cavity.

[0003] In the dry etching cleaning process, special gases (usually Cl2, F2, ClF3, etc.) will also react chemically with SiO2 on the surface of the quartz wall in the furnace tube, causing damage to the quartz wall surface or reducing the polarity of the surface molecules, which is not conducive to the adhesion of the film. When the film is not tightly attached, it is easy to fall off during the process, thus forming contaminated particles. Therefore, in the dry etching cleaning process, the endpoint judgment of dry etching is very important, that is, both removing the silicon layer and 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 reacting with the silicon layer. Usually, the temperature floating value (±1°C, ±0.5°C, etc.) can be set according to the temperature change process displayed by the thermocouple inside the chamber to control the end point of dry etching of the silicon layer. 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 end point 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 cause corrosion to the quartz wall of the furnace tube, affecting the life of the furnace tube equipment and the process indicators during use. Summary of the invention

[0008] The technical problem to be solved by the present application is to provide an optical detection device which is independent of temperature detection and can timely and accurately obtain the film thickness 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.

[0009] 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 intracavity capillary, wherein the intracavity capillary is arranged in a furnace tube device, the top end of the intracavity 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 axial direction of the intracavity capillary to the interior of the intracavity capillary; the light sensing unit is used to receive reflected light reflected back from the light-transmitting reflective plane of the intracavity capillary; the optical detection device is configured to: obtain the thickness of the film layer deposited on the light-transmitting reflective plane according to the reflected light.

[0010] In one embodiment of the present application, the material of the light-transmitting and light-reflecting plane is quartz.

[0011] In one embodiment of the present application, the material of the intracavitary capillary is quartz.

[0012] 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.

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

[0014] In one embodiment of the present application, the inner diameter of the intracavitary tube ranges from 0 to 100 mm.

[0015] In one embodiment of the present application, the inner diameter of the intracavitary tube is in the range of 5-15 mm.

[0016] In one embodiment of the present application, the inner diameter of the intracavitary tube is in the range of 2-10 mm.

[0017] In one embodiment of the present application, the wall thickness of the intracavitary tube is in the range of 0.2-3 mm.

[0018] 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.

[0019] In an embodiment of the present application, the light source and the light sensing unit are arranged outside the furnace tube device.

[0020] In one embodiment of the present application, an optical module is further included, which is disposed 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.

[0021] In one embodiment of the present application, it also includes a light-passing pipe, which is arranged between the optical module and the intracavitary capillary, and the light-passing pipe and the intracavitary capillary are connected to each other through a bending connection portion, and a dimming device is provided in the bending connection portion, and 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 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 an axial direction parallel to the light-passing pipe and be received by the light sensing unit.

[0022] 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.

[0023] 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 light intensity of the reflected light.

[0024] To solve the above technical problems, the present application also proposes a furnace tube device, including a heating outer sleeve, 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.

[0025] 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.

[0026] In order to solve the above-mentioned technical problems, the present application also proposes a control method for the cleaning end point of a 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.

[0027] The optical detection device of the present application uses an intracavitary capillary to detect the thickness of the deposited film layer. The light-transmitting reflective plane at the top of the intracavitary capillary has a first optical parameter different from that of the deposited film layer. Therefore, the reflected light from the light-transmitting reflective plane can reflect the thickness of the film layer deposited on the light-transmitting 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 the temperature detection device and will not be affected by the temperature, thus avoiding the problem of using a thermocouple to detect temperature changes to control the end point of dry cleaning. At the same time, due to the fast 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 obtained quickly and accurately, thereby achieving effective monitoring of the end point of dry cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0029] Figure 1 is a schematic structural diagram of an optical detection device according to an embodiment of the present application;

[0030] Figure 2 is a schematic structural diagram of an optical detection device according to another embodiment of the present application;

[0031] Figure 3 is a schematic diagram of a curve showing the relationship between the thickness of a silicon film and the intensity of reflected light obtained by performing optical simulation based on the principle of a light detection device according to an embodiment of the present application;

[0032] Figure 4 is a schematic diagram of a furnace tube device according to an embodiment of the present application;

[0033] Figure 5 It is an exemplary flow chart of a method for controlling the cleaning endpoint of a furnace tube equipment according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0035] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps 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 accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0037] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present 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, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0038] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. 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 figure. For example, if the device in the accompanying 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.

[0039] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0040] The optical detection device for detecting the thickness of deposited film layers of the present application can be used to detect the thickness of deposited film layers involved in any process of semiconductor technology. In particular, it is used to detect the thickness of film layers in real time during the dry cleaning process of furnace tube equipment to help determine and control the end point of dry cleaning reaction and avoid over-reaction and under-reaction.

[0041] Figure 1 Schematic diagram of an optical detection device for detecting the thickness of a deposited film layer according to an embodiment of the present application. Figure 1 As shown, the optical detection device 100 of this embodiment includes a light source 110, a light sensing unit 120 and an intracavitary capillary 130, wherein the intracavitary capillary 130 is used to be arranged in the furnace tube device 101, and the top of the intracavitary capillary 130 is a light-transmitting and light-reflecting plane 131, as shown in FIG. Figure 1 The material of the light-transmitting and light-reflecting plane 131 has a first optical parameter, and the deposited film layer has a second optical parameter, and the first optical parameter is different from the second optical parameter.

[0042] like Figure 1As shown, 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 is made of a light-transmitting material, and the light emitted by the light source 110 can propagate in 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 in 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.

[0043] like Figure 1 As shown, the intracavitary capillary 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 130 is parallel to the axial direction of the furnace tube. That is to say, if the axial direction of the furnace tube is in the vertical direction, the axial direction of the intracavitary capillary 130 is also in the vertical direction; if the axial direction of the furnace tube is in the horizontal direction, the axial direction of the intracavitary capillary 130 is also in the horizontal direction. It should be noted that when the axial direction of the furnace tube is in the vertical direction, the surface of the wafer is arranged parallel to the horizontal direction, and when the axial direction of the furnace tube is in the horizontal direction, the surface of the wafer is arranged parallel to the vertical direction.

[0044] like Figure 1 As shown, 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 film deposition process, the thickness of the film deposited on the light-transmitting reflective plane 131 is almost equal to the thickness of the film on the inner wall of the furnace tube. Therefore, the thickness of the film on the light-transmitting reflective plane 131 can reflect the thickness of the 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 is not strictly equal, and generally there is a small difference of ±1nm.

[0045] In some embodiments, the wall thickness of the intracavitary capillary 130 is in the range of 0.2-3 mm, and similarly, the thickness of the light-transmitting and light-reflecting plane 131 is also in the range of 0.2-3 mm. For example, the thickness may be 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, etc. The wall of the intracavitary capillary 130 and the light-transmitting and light-reflecting plane 131 at the top may be integrally formed.

[0046] The first optical parameter and the second optical parameter mentioned above refer to the optical properties exhibited when the light irradiates the light-transmitting and light-reflecting plane 131 and the deposited film layer, such as reflectivity, refractive index, transmittance, etc.

[0047] It should be noted that, for the same light, the first optical parameter is different from the second optical parameter.

[0048] 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 two are different.

[0049] The inventors of the present application have found 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 5nm, the optical reflectivity will change significantly. One embodiment of the present application uses quartz to form the light-transmitting reflective plane 131, so that it 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.

[0050] In some embodiments, only the light-transmitting and light-reflecting surface 131 of the intracavitary capillary 130 is made of quartz, and the other parts may be made of other materials.

[0051] In some embodiments, the entire material of the intracavitary capillary 130 is quartz, that is, it is a quartz capillary.

[0052] In some embodiments, the first optical parameter also includes the extinction coefficient of the light-transmitting reflective plane 131 to the incident light, and the second optical parameter also includes the extinction coefficient of the deposited film layer to the incident light. For example, the extinction coefficient of silicon ranges from 0 to 0.75, and the extinction coefficient of silicon dioxide is 0, and there is a significant difference between the two. Combined with the difference in the refractive index of the above two materials, when the thickness of the silicon film deposited on the light-transmitting reflective plane 131 increases from 0 to 5nm, the optical reflectivity will change significantly.

[0053] like Figure 1 As shown, the light source 110 and the light sensing unit 120 are both arranged outside the furnace tube device 101. Of course, if the light source 110 and the light sensing unit 120 are both resistant to high temperatures, they can also be arranged inside the furnace tube device 101, or in a low-temperature chamber in the furnace tube device 101, and the present application does not limit this.

[0054] like Figure 1 , the light source 110 is used to provide incident light parallel to the axis of the intracavitary capillary 130 to the inside of the intracavitary capillary 130. The present application does not limit the connection method between the light source 110 and the intracavitary capillary 130, as long as parallel incident light can be provided to the inside of the intracavitary capillary 130. According to such a configuration, parallel light is transmitted in the intracavitary capillary 130 and directly reaches the light-transmitting reflective plane 131. A 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 capillary 130. Since the propagation of parallel light in the intracavitary capillary 130 is not easy to disperse, 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.

[0055] In some embodiments, the light source 110 and the light sensing unit 120 may be independently provided or integrally provided.

[0056] In some embodiments, the light source 110 is configured to provide light waves with wavelengths ranging from visible light to near infrared light.

[0057] 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.

[0058] In some embodiments, the controller may be integrated with the light source 110 and the light sensing unit 120 .

[0059] The optical detection device of the present application replaces the conventional method of using thermocouples to measure temperature changes for process control, thereby avoiding various problems in the use of thermocouples. In addition, due to the fast transmission speed of optical signals, the interference of the furnace tube heating process on the optical signal is very small, and the film thickness can be obtained quickly and accurately, thereby realizing effective monitoring of the dry cleaning end point.

[0060] Figure 2 Schematic diagram of the structure of an optical detection device according to another embodiment of the present application. Figure 2 As shown, the optical detection device 200 of this embodiment is Figure 1On the basis of the illustrated embodiment, in addition to the light source 110, the light sensing unit 120 and the intracavitary capillary 130, an optical module 210 is also included, 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 setting 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. Figure 2 The illustration 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 .

[0061] Further, refer to Figure 2 The optical detection device 200 further includes a light-passing pipe 220, which is disposed between the optical module 210 and the intracavitary capillary 130. The light-passing pipe 220 and the intracavitary capillary 130 are connected to each other through a bent connection portion 230, and a dimming device 231 is provided in the bent connection portion 230. The dimming device 231 is used to reflect incident light, and make the incident light after reflection propagate inside the intracavitary capillary 130 along the axial direction parallel to the intracavitary capillary, and reach the light-transmitting and reflecting plane 131, and the dimming device 231 is also used to reflect the reflected light reflected from the light-transmitting and reflecting plane 131, and make the reflected light propagate in the light-passing pipe 220 along the axial direction parallel to the light-passing pipe, and be received by the light sensing unit 120.

[0062] In some embodiments, the bent connection portion 230 is a metal joint having a right-angle bent structure.

[0063] like Figure 2 As shown, the light-passing pipe 220 and the intracavitary capillary 130 are vertically connected to each other through the bent connecting portion 230, that is, the axial angle between the two is 90 degrees. In other embodiments, the angle may also be other angles, which is not limited in the present application.

[0064] like Figure 2 As shown, 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 angles between the dimming device 231 and the axis of the light pipe and the axis of the intracavitary capillary are both 45 degrees, so that the parallel light in the light pipe 220 can be reflected as parallel light parallel to the axis of the intracavitary capillary. It can be understood that when the angle is not 90 degrees, the propagation direction of the light can be controlled by setting the angle of the reflector or increasing the number of reflectors.

[0065] like Figure 2 As shown, in this embodiment, the optical module 210 can be arranged in the light pipe 220, for example, near the outward exit, to adjust the light waves entering the light pipe 220. In some embodiments, the optical module 210 can also include a filter for adjusting the wavelength of the light wave to an appropriate wavelength according to the actual sensing accuracy requirements.

[0066] like Figure 2 As shown, 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 passage 220 .

[0067] 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 .

[0068] In some embodiments, in order to achieve synchronous measurement of light, the dimming device 231 is a semi-transparent mirror inclined at 45 degrees, so that the incident light can enter the intracavitary capillary 130 after being reflected by the semi-transparent mirror, and the reflected light can pass directly after passing through the light-transmitting and reflective plane 131, thereby achieving the measurement of reflected light while emitting light.

[0069] refer to Figure 2 In some embodiments, the optical detection device 200 further includes a connector 240 for fixing the intracavitary capillary 130 to the bent connecting portion 230. A sealing device 250 may also be included for sealing the connection between the bent connecting portion 230 and the intracavitary capillary 130.

[0070] In some embodiments, the step of obtaining the thickness of the film layer deposited on the light-transmitting and light-reflecting plane according to the reflected light by the optical detection device of the present application 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.

[0071] The inventors of the present application have discovered through experiments that after light is reflected by silicon films of different thicknesses, it will be weakened to varying degrees, and the light intensity reaches the lowest value when the thickness of the silicon film is 0. Figure 3 This is a relationship curve between silicon film thickness and reflected light intensity obtained by optical simulation based on the principle of the light detection device of this application. Figure 3 , the horizontal axis is the silicon film thickness (Thickness), the unit is nm, and the vertical axis is the percentage of the reflected light intensity relative to the incident light intensity (Reflectance), the unit is %. 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, refer to Figure 3, relative to the intensity of the incident light, when the thickness of the silicon film is 50nm, the intensity of the reflected light is about 63% of the intensity of the incident light; at 10nm and 5nm, the intensity of the reflected light is only 16% and 7% of the intensity of the incident light, respectively. Therefore, the optical simulation method can be used to select one or several light waves, and the test results can be stored through the obtained light signal intensity of the reflected light, or the ratio of the reflected light intensity to the incident light intensity, and used to accurately judge the thickness of the silicon film. According to the test results, in practical applications, the conditions can also be accurately set to control the thickness of the silicon film at a stage where the thickness is relatively thin or just becomes zero during the dry etching process.

[0072] The present application does not impose any limitation on the length or height of the intracavitary tube 130 .

[0073] Figure 4 Schematic diagram of a furnace tube device according to an embodiment of the present application. Figure 4 As shown, the furnace tube device 400 includes a heating outer sleeve 410, and the furnace tube device 400 is connected to the optical detection device described above in the present application, wherein the intracavitary capillary 130 is arranged inside the heating outer sleeve 410, and the intracavitary capillary 130 is arranged parallel to the heating outer sleeve 410. Figure 4 The figure shows a vertical furnace tube device. Assuming that the outer heating sleeve 410 is extended in the vertical direction, the intracavitary capillary 130 also extends in the vertical direction, and the two are parallel to each other. Figure 4 The optical detection device shown in Figure 2 The optical detection device 200 shown in FIG. 1 is a device for detecting an optical component of a semiconductor device 200, wherein the light source 110 and the light sensing unit 120 are not shown. Figure 1 The optical detection device 100 is shown.

[0074] In some embodiments, the heating outer sleeve 410 further includes an inner liner tube 420 . When semiconductor thin film deposition is performed, the wafer W is disposed inside the inner liner tube 420 , wherein the intracavitary capillary 130 is disposed in the outer space of the inner liner tube 420 .

[0075] refer to Figure 4 The process gas GAS can be passed into the chamber from the inner liner tube 420. There is a vacuum pipeline 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 as follows: Figure 4As shown by the arrow in , it rises from the bottom of the liner tube 420 to the top of the liner tube 420, then enters the space between the liner tube 420 and the heating outer sleeve 410 from the top downward, 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 film 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 liner tube 420.

[0076] Similar to the deposition process, during the dry cleaning process of the furnace tube wall, the gathering and flow of the special gas used for the dry etching reaction also show the same Figure 4 The same rule is shown by the arrow in the figure. Therefore, at the higher position P1, the etching reaction for 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 at position P1 and the change in dry cleaning are close to those inside the inner liner tube 420, in the cleaning process of the furnace tube wall, the thin film also needs to be completely removed at the bottom of the furnace tube and at positions where the gas diffusion is weak, that is, not only the complete removal of the tube wall thin film inside the inner liner tube 420 is required, but also the thin film deposited at the bottom of the external heating outer sleeve 410 needs to be reacted off. According to the working order of the dry cleaning gas in the furnace tube cavity, only when the thin film at position P2 or P3 is removed by reaction, can it be said that the tube walls of the inner liner tube 420 and the external heating outer sleeve 410 have been effectively dry cleaned. Taking this into consideration, the design of the height or length of the intracavitary capillary 130 needs to be considered. If the transparent reflective plane 131 is too close to the bottom of the furnace tube device 400, although the film on the tube wall of the furnace tube can be effectively removed, the quartz on the tube wall of the chamber may also be etched, resulting in over-etching. If the position of the transparent reflective plane 131 is too high, when the film thickness on the transparent reflective plane 131 has reached the preset thickness, the film thickness on the tube wall at the bottom or near the bottom of the furnace tube device 400 is still relatively thick, which will lead to insufficient etching. Therefore, the height of the intracavitary capillary 130 should be set near position P2, or between positions P2 and P3, to achieve better process effects.

[0077] In some embodiments, the height of the intracavitary capillary 130 is less than the height of the internal cavity of the furnace tube device 400. The optimal height can be determined according to the actual machine design and related settings. In some embodiments, the height of the intracavitary capillary 130 is less than or equal to 2 / 3 of the height of the internal cavity of the furnace tube device 400. The ratio of the height of the intracavitary capillary 130 to the internal height of the furnace tube device 400 can be 2 / 3, 1 / 3, 1 / 4, 2 / 5, etc.

[0078] In some embodiments, assuming that the internal 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.

[0079] The furnace tube equipment 400 of the present application has a built-in intracavitary capillary 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.

[0080] Figure 5 FIG. 4 is an exemplary flow chart of a method for controlling a furnace tube device cleaning endpoint 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. Figure 5 The control method of the furnace tube equipment cleaning endpoint of this embodiment includes:

[0081] Step S510: In the dry cleaning process of the furnace tube equipment, the optical detection device 100, 200 of the present application is used to detect the thickness of the film layer on the light-transmitting and light-reflecting plane 131;

[0082] Step S520: When the film thickness reaches a preset value, the dry cleaning process of the furnace tube equipment is stopped.

[0083] The control method can effectively control the end point of the dry cleaning process and avoid insufficient etching and excessive etching.

[0084] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0085] At the same time, the present application uses specific words to describe the embodiments of the present 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 the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0086] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0087] In some embodiments, numbers describing the number of components and attributes are used. 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 specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification 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 setting of such numerical values ​​is 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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