A reflectivity optical measuring device

Abstract

The present invention discloses an optical reflectivity measurement device, which is arranged outside a reaction chamber and includes: a light emitting module and a light detection module; the light emitting module is used to emit incident detection light, the light emitting module includes a light emitting surface that emits the incident detection light, the incident detection light is non-parallel light, at least part of the incident detection light is projected onto the measured surface of the object to be measured in the reaction chamber through an observation port on the reaction chamber, and is reflected by the measured surface; the light detection module is used to receive the outgoing detection light reflected by the measured surface and emitted through the observation port. The present invention can provide effective measurement of reflectivity by using a light emitting module with a light emitting surface to emit non-parallel light as the incident detection light, thereby making the optical path adjustment simpler, and the measuring device is not subject to excessive restrictions on the installation position, thereby achieving the purpose of simplifying the optical path and increasing reliability. It is suitable for measuring epitaxial wafers that produce large warping, broadening the application scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device manufacturing, and in particular to a reflectivity optical measuring device. Background Art

[0002] In the semiconductor device manufacturing process, the growth temperature of the epitaxial wafer is a key parameter for controlling thin film growth. Due to the strict reaction conditions in the thin film growth reaction chamber, it is necessary to rely on non-contact temperature measurement methods to measure the epitaxial wafer growth temperature.

[0003] The non-contact temperature measurement method currently used in the art uses a high-temperature measurement method that has been corrected for the thermal emissivity. This method calculates the surface temperature of the epitaxial wafer by measuring the emissivity of the corresponding epitaxial wafer surface and the radiated light within a certain wavelength band. Therefore, an optical measurement system is required to measure the reflectivity and obtain the emissivity information.

[0004] Typically, an observation port is located at the top of the reaction chamber, through which the optical measurement system transmits a probe beam toward the epitaxial wafer. The probe beam reflects off the epitaxial wafer surface, forming a reflected beam that is detected by a detector to obtain the reflectivity. Based on the intensity of the detected reflected beam and the known intensity of the incident light, a calculation control unit calculates the reflectivity R of the epitaxial wafer surface at the point of reflection. Furthermore, using the formula ε = 1 - R, the epitaxial wafer's emissivity ε is calculated. From this emissivity ε, the epitaxial wafer's surface temperature can be calculated.

[0005] Due to the unique structure of the epitaxial reactor, the position and size of the observation port are strictly limited. Conventional optical measurement systems use parallel beams (e.g., narrow parallel beams emitted by lasers). These beams must pass through a complex optical path to converge the collimated laser light into a narrow incident beam. This beam then passes through the observation port at the top of the reactor (meaning the incident beam must be smaller than the size of the port), projecting perpendicularly onto the epitaxial wafer and reflecting off the surface.

[0006] Furthermore, traditional optical measurement systems are subject to limitations in the light source's mounting position (e.g., requiring the use of a beam splitter), making it difficult to achieve a perfect match between the light source and the observation port. This makes installation difficult during commissioning and subsequent maintenance cumbersome. Any misalignment in the mounting position can prevent the detection of reflected light signals, affecting temperature measurement stability and preventing consistent and accurate temperature measurements of epitaxial wafer growth.

[0007] At the same time, due to stress during thin film growth, the epitaxial wafer can warp, causing some of the reflected light beam to bend at an angle, preventing it from exiting through the observation port and being received by the detector. When the warping is significant, because the laser emits parallel light, even if the laser's emitting surface is infinitely large, no light signal will be reflected and reach the detector. In other words, when using parallel light detection, it is easily affected by factors such as the surface condition of the object being measured, making it difficult to accurately obtain reflectivity through measurement.

[0008] Therefore, it is necessary to provide a new reflectivity optical measurement technology to solve the above problems existing in the prior art. Summary of the Invention

[0009] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a reflectivity optical measuring device.

[0010] To achieve the above object, the technical solution of the present invention is as follows:

[0011] The present invention provides a reflectivity optical measurement device, which is arranged outside a reaction chamber and includes: a light emitting module and a light detecting module;

[0012] The light emitting module is configured to emit incident detection light, the light emitting module comprising a light emitting surface for emitting the incident detection light, the incident detection light being non-parallel light, at least a portion of the incident detection light being projected onto a surface of the object to be detected in the reaction chamber through an observation port on the reaction chamber, and being reflected by the surface;

[0013] The light detection module is used to receive the outgoing detection light reflected by the measured surface and emitted through the observation port.

[0014] Furthermore, the intensity of the incident detection light emitted at each point on the light-emitting surface is uniformly distributed within the solid angle normal to the light-emitting surface, and the intensity distribution at each point within the solid angle is consistent; half of the angle opened by the solid angle in any direction is defined as β, and β is greater than or equal to the half-apex angle α of the cone formed between the projection of the center of the observation port on the plane where the object to be measured is located and the observation port.

[0015] Furthermore, the size A of the light emitting surface and the size B of the observation port satisfy:

[0016] A / B≥H / h

[0017] Wherein, H is the distance from the light emitting surface to the plane where the object to be measured is located, and h is the distance from the observation port to the plane where the object to be measured is located.

[0018] Furthermore, the dimension A of the light emitting surface and the dimension B of the observation port satisfy the following relationship: H / h≤A / B≤2H / h.

[0019] Furthermore, the light emitting module includes a surface light source, which constitutes the light-emitting surface of the incident detection light. The surface light source is arranged facing the observation port, and a receiving hole is provided on the surface of the surface light source. The light detection module receives the outgoing detection light reflected by the measured surface and emitted through the observation port through the receiving hole, wherein the receiving hole, the light detection module and the observation port are arranged in a center-aligned manner.

[0020] Furthermore, the light emitting module includes: a surface light source and a first lens;

[0021] The surface light source emits the incident detection light;

[0022] The first lens is located between the surface light source and the observation port, and is used to transmit and focus the incident detection light from the surface light source, and form an image of the surface light source at a position between the first lens and the observation port, and the image of the surface light source constitutes the light-emitting surface of the incident detection light;

[0023] The surface light source is provided with a receiving hole penetrating the surface, and the light detection module receives the outgoing detection light reflected by the measured surface and emitted through the observation port through the receiving hole, wherein the receiving hole, the light detection module and the observation port are arranged in a centrally aligned manner.

[0024] Furthermore, the image of the surface light source is located at the location of the observation port.

[0025] Furthermore, the size C of the surface light source and the size B of the observation port satisfy the following relationship:

[0026] C / B≥f / (vf)

[0027] Wherein, f is the focal length of the first lens, and v is the distance from the image of the surface light source to the first lens.

[0028] Furthermore, the light emitting module includes: a surface light source, a second lens and a light splitting module;

[0029] The surface light source emits the incident detection light;

[0030] The light splitting module is used to transmit / reflect the incident detection light from the surface light source toward the observation port, and to reflect / transmit the outgoing detection light reflected by the object to be measured and emitted through the observation port toward the light detection module accordingly;

[0031] The second lens is used to transmit and focus the incident detection light from the surface light source. The surface light source forms an image of the surface light source at a position above the observation port through the action of the second lens and the light splitting module. The image of the surface light source constitutes the light-emitting surface of the incident detection light.

[0032] The light detection module and the observation port are arranged in a centrally aligned manner, or the image formed by the light detection module with respect to the light splitting module and the observation port are arranged in a centrally aligned manner.

[0033] Furthermore, the surface light source includes an LED surface light source, or the surface light source is formed by a point light source or laser irradiating frosted glass, or the surface light source includes a light source with Lambertian radiator properties.

[0034] Furthermore, the reflectivity optical measurement device also includes a control module, the light detection module includes a light intensity detector, the light intensity detector detects the light intensity signal of the outgoing detection light and transmits the light intensity signal to the control module, and the control module calculates the reflectivity of the object to be measured based on the intensity of the incident detection light and the intensity of the outgoing detection light.

[0035] Furthermore, the reaction chamber is a MOCVD reaction chamber.

[0036] Compared to the prior art, which uses a complex optical path to converge a parallel, collimated light beam (e.g., a laser) into an incident light beam, which is then projected vertically from the center of an observation port onto the object to be measured and reflected from the surface of the object to be measured, the reflectivity optical measurement device provided by the present invention utilizes a light emitting module with a specific light-emitting surface to emit non-parallel light as the incident probe light. This ensures that, regardless of the installation offset between the optical measurement device and the observation port on the reaction chamber, or the object to be measured is warped or tilted, the incident probe light emitted from the light-emitting surface can still enter the observation port, be reflected by the object to be measured, and then be emitted through the observation port to be detected by the light detection module. This simplifies optical path adjustment and frees the measurement device from excessive installation restrictions, thereby simplifying the optical path and increasing reliability. The device is particularly suitable for measuring objects with significant warping. Furthermore, by matching the size of the light emitting surface of the light emitting module with the size of the observation port and designing the solid angle range to ensure uniform and consistent light intensity distribution, the reflectivity measurement and, based on this, temperature measurement can be further ensured to be effective. In addition, the arrangement position of the optical transmission module of the present invention can meet various installation requirements and can be adjusted according to the requirements of the on-site equipment site, thereby broadening the application scenarios of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1-Figure 3This is a schematic structural diagram of a reflectivity optical measurement device according to a preferred embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the optical path of laser imaging in the prior art;

[0039] Figure 5 This is a principle diagram of the optical path for imaging a surface light source according to the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the invention belongs. The words "including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0041] The present invention provides an optical reflectivity measurement device disposed outside a reaction chamber. The reaction chamber may be a film-forming device used in a high-temperature semiconductor growth process. The film-forming device includes a vapor-phase reaction device, such as a metal organic chemical vapor deposition device (MOCVD), a hydride vapor phase epitaxy device (HVPE), a plasma-enhanced chemical vapor deposition device, or a physical vapor deposition device (PVD). The reaction chamber is provided with an observation port, through which the optical reflectivity measurement device performs online reflectivity measurement of an object to be measured placed in the reaction chamber. The object to be measured may be, for example, a tray or a wafer on the tray, which rotates during epitaxial growth.

[0042] The reflectivity optical measurement device includes a light emitting module and a light detection module; the light emitting module is used to emit incident detection light, and the light emitting module includes a light-emitting surface that emits the incident detection light. The incident detection light is non-parallel light and has a certain divergence angle. At least a portion of the incident detection light is projected onto the measured surface of the object to be measured in the reaction chamber through the observation port on the reaction chamber and is reflected by the measured surface; the light detection module is used to receive the outgoing detection light reflected by the measured surface and emitted through the observation port.

[0043] In some embodiments, the reflectivity optical measurement device further includes a control module. In some embodiments, the light detection module includes a light intensity detector that detects a light intensity signal of the outgoing detection light and transmits the light intensity signal to the control module. The control module calculates the reflectivity of the object to be measured based on the intensity of the incident detection light and the intensity of the outgoing detection light, thereby obtaining emissivity information, and thereby calculating the temperature of the object to be measured according to the Planck equation.

[0044] In some embodiments, the light-emitting surface emitting the incident detection light is arranged opposite to the observation port, and the size of the light-emitting surface meets certain requirements, so that within the size range of the given observation port, it can be guaranteed that there is incident detection light that can enter the observation port, and there is outgoing detection light that can be emitted from the observation port. Define H as the distance from the light-emitting surface emitting the incident detection light to the plane where the object to be measured is located, and h as the distance from the observation port to the plane where the object to be measured is located, then the size A of the light-emitting surface and the size B of the observation port meet the following relationship: A / B ≥ H / h. Preferably, H / h ≤ A / B ≤ 2H / h. By matching the size of the light-emitting surface and the size of the observation port, the measurement of reflectivity can be ensured.

[0045] In some embodiments, if the object to be measured is warped, the dimensions of the observation port must meet certain requirements to ensure that the incident probe light can enter the observation port and the outgoing probe light can exit the observation port. The warp is characterized by the object's inclination γ (i.e., the angle between the tangent line at the measured point and the horizontal plane), and the half-apex angle α is ≥ 2γ. The design dimensions of the observation port within a certain warp range can be determined by using the half-apex angle α and the distance h from the observation port to the plane of the object to be measured. Within this observation port size range, reflectivity measurements can be performed within an object's inclination ≤ γ.

[0046] In some embodiments, the intensity distribution of the incident detection light emitted at each point on the light-emitting surface from which the incident detection light is emitted is uniform within a certain solid angle normal to the light-emitting surface. Preferably, the intensity non-uniformity (the ratio of the standard deviation of the intensity value to the intensity average) is less than or equal to 2%, and the intensity distribution within the solid angle is consistent between each point, thereby further ensuring that the obtained reflectivity can be effectively used without affecting the stability of temperature measurement. Otherwise, the reflectivity will fluctuate due to the different intensities of the incident detection light, and it cannot represent the true reflectivity and cannot be used to calculate the temperature. Specifically, half of the angle opened by the solid angle in any direction is defined as β, and the β is greater than or equal to the half-apex angle α of the cone formed between the projection of the center of the observation port on the plane where the object to be measured is located and the observation port. Preferably, the range of β / α is 1 to 2.

[0047] The reflectivity optical measurement device provided by the present invention utilizes a light emitting module with a specific light-emitting surface to emit non-parallel light as incident probe light. This ensures that, regardless of the installation offset between the optical measurement device and the observation port on the reaction chamber, or the warping or tilting of the object to be measured, although light incident perpendicularly on the object to be measured from the center of the observation port cannot be detected, incident probe light emitted from other positions or angles on the light-emitting surface can still enter the observation port, be reflected by the object to be measured, and then be emitted through the observation port and detected by the light detection module. This simplifies optical path adjustment and frees the measurement device from excessive restrictions on installation position, thereby simplifying the optical path and increasing reliability. The device is particularly suitable for measuring objects to be measured with significant warping. Furthermore, the light emitting surface size of the light emitting module and the uniform distribution and consistent solid angle range of the luminous intensity are designed to further ensure that reflectivity measurement and, based on this, temperature measurement can be effectively used.

[0048] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Example 1

[0050] See also Figure 1 , Figure 1 FIG. 1 is a schematic structural diagram of a reflectivity optical measuring device according to a preferred embodiment of the present invention. Figure 1 As shown in FIG. 1 , a reflectivity optical measuring device of the present invention comprises a light emitting module and a light detecting module 13 disposed above an observation port 11 . The light emitting module comprises a surface light source 12 .

[0051] The observation port 11 is located above the object to be measured 10. The surface light source 12 forms the light-emitting surface of the incident probe light and is used to emit the incident probe light, which is non-parallel light. After passing through the observation port 11, at least a portion of the incident probe light emitted from the surface light source 12 is projected onto the measured surface of the object to be measured 10 below. The light detection module 13 is used to receive the outgoing probe light reflected by the measured surface and emitted through the observation port 11.

[0052] See also Figure 1 In some embodiments, the surface light source 12 may have a planar (or approximately planar) light-emitting surface. Furthermore, the light-emitting surface of the surface light source 12 may be disposed facing the observation port 11 so that the two are parallel to each other.

[0053] At the same time, the surface light source 12 may be provided with a receiving hole extending through the surface of the surface light source 12. The light detection module 13 may be positioned above the receiving hole. In this way, the light detection module 13 can receive, through the receiving hole, the outgoing detection light reflected from the surface being measured and emitted through the observation port 11.

[0054] In some embodiments, the aperture of the receiving hole is greater than or equal to the size of the detection surface of the light detection module 13 .

[0055] In this embodiment, an integrated measurement system is used. By opening a hole in the center of the surface light source 12 as a detection hole (receiving hole) of the light detection module 13, many optical elements are omitted and the light path is simplified.

[0056] In some embodiments, the light detection module 13 may be directly disposed in the receiving hole. Furthermore, the detection surface (lower surface) of the light detection module 13 may be flush with the light emitting surface (lower surface) of the surface light source 12 .

[0057] See also Figure 1 In some embodiments, the horizontal width A of the surface light source 12 and the horizontal width B of the observation port 11 meet certain conditions to ensure that, regardless of installation offset or warping of the epitaxial wafer, incident detection light can enter the observation port 11 and be reflected by the object to be measured 10 before being emitted through the observation port 11 and detected by the light detection module.

[0058] Specifically, see Figure 1 In some embodiments, the receiving hole, the light detection module 13, and the observation port 11 may be arranged in a centrally aligned manner. Preferably, the surface light source 12 is also arranged in a centrally aligned manner with the receiving hole, the light detection module 13, and the observation port 11. The horizontal width A of the surface light source 12 may satisfy the following conditions:

[0059] The first intersection point formed on the measured surface by the line connecting the center of the light detection module 13 (receiving hole) and the center of the observation port 11 is defined as the first endpoint o (i.e., the projection of the center of the observation port 11 on the plane where the object 10 to be measured is located). The two side edges of the observation port 11 are defined as the second endpoint p and the third endpoint q. A straight line is drawn between the first endpoint o and the second endpoint p and extended to the surface light source 12 to form a second intersection point s. Simultaneously, a straight line is drawn between the first endpoint o and the third endpoint q and extended to the surface light source 12 to form a third intersection point t. The endpoints o, s, and t form an isosceles triangle. A straight line is drawn between the endpoints o and s. The angle formed between the straight line and the center line is the half-apex angle α of the cone formed between the projection of the center of the observation port 11 on the plane where the object 10 to be measured is located and the observation port 11. H is defined as the distance from the surface light source 12 to the plane where the object 10 to be measured is located, and h is defined as the distance from the observation port 11 to the plane where the object 10 to be measured is located.

[0060] In this state, the horizontal width A of the surface light source 12 is greater than or equal to the distance M between the second intersection s and the third intersection t, where M = 2H * tgα. The horizontal width B of the observation port 11 is the distance between endpoints p and q, where B = 2h * tgα, meaning M / B = H / h. Since width A is greater than or equal to distance M, A / B ≥ H / h. In this way, by matching the dimensions of the light-emitting surface and the observation port, reflectivity measurement can be ensured.

[0061] In some embodiments, the distance H between the surface light source 12 and the plane where the object to be measured 10 is located may be within 500 mm.

[0062] In some embodiments, the distance h from the observation port 11 to the plane where the object to be measured 10 is located may be between 100 mm and 200 mm.

[0063] In some embodiments, the ratio of the width A of the surface light source 12 in the horizontal direction to the distance M between the second intersection s and the third intersection t may be 1 to 2 times, that is, H / h≤A / B≤2H / h.

[0064] In some embodiments, the intensity distribution of the incident probe light emitted from each location on the light-emitting surface of the surface light source 12 is uniform and consistent within a certain solid angle normal to the light-emitting surface, further ensuring that the obtained reflectivity can be effectively used without affecting the stability of temperature measurement. In some embodiments, the surface light source 12 may include a light source with Lambertian radiator properties, so that the intensity distribution of the incident probe light emitted from each location on the light-emitting surface is uniform and consistent within a certain solid angle normal to the light-emitting surface.

[0065] Specifically, see Figure 1 In some embodiments, the surface light source 12, the receiving hole, the light detection module 13, and the observation port 11 are arranged in a centrally aligned manner, and the surface light source 12 directly emits the detection light toward the observation port 11 (i.e., there is no obstruction between the surface light source 12 and the observation port 11). Half of the angle opened by the solid angle in any direction is defined as β, and β may satisfy the following condition: β is greater than or equal to the half-vertex angle α.

[0066] In some embodiments, the ratio between β and the half apex angle α may range from 1 to 2.

[0067] The above-mentioned matching of the size and position relationship between the surface light source 12 and the observation port 11 can ensure that the detection light emitted by the surface light source 12 (Lambertian illuminator) can achieve the best incident effect in all directions.

[0068] In some embodiments, the surface light source 12 may further include an LED surface light source 12 .

[0069] In some embodiments, the surface light source 12 may also be formed by a point light source or laser irradiating frosted glass.

[0070] In this first embodiment, a surface light source 12 with a defined luminous surface is used to emit non-parallel light as the incident probe light. Furthermore, by matching the dimensions of the surface light source 12 with the observation port 11, the luminous surface size of the probe beam is equal to or greater than the size of the observation port 11. This differs from the prior art, which uses a complex optical path to converge laser light into an incident laser beam smaller than the observation port 11. This simplifies optical path adjustment and eliminates excessive installation restrictions on the probe beam. Furthermore, the design ensures a uniform and consistent distribution of luminous intensity over a solid angle range, ensuring that the resulting reflectivity is effectively usable in temperature measurement applications.

[0071] Example 2

[0072] See also Figure 2 The difference between Example 2 and Example 1 is that the light emitting module in this embodiment includes a surface light source 12 and a first focusing imaging module 14 .

[0073] In some embodiments, a first focusing imaging module 14 is disposed between the surface light source 12 and the observation port 11. The first focusing imaging module 14 is configured to transmit and focus the probe light from the surface light source 12, and to form a first real image 15 of the surface light source 12 at a position between the first focusing imaging module 14 and the observation port 11. In this embodiment, the first real image 15 of the surface light source 12 constitutes the luminous surface of the incident probe light.

[0074] In some embodiments, the first light-collecting imaging module 14 may include a first lens.

[0075] In some embodiments, the first lens is disposed parallel to and between the surface light source 12 and the observation port 11 , and the centers of the first lens, the surface light source 12 , and the observation port 11 are aligned.

[0076] Similarly, the horizontal width A' of the first real image 15 of the surface light source 12 and the horizontal width B of the observation port 11 must meet certain conditions to ensure that, regardless of installation offset or warping of the epitaxial wafer, incident detection light can enter the observation port 11 and be reflected by the object to be measured 10 before being emitted through the observation port 11 and detected by the light detection module 13. Define H as the distance from the first real image 15 of the surface light source 12 to the plane where the object to be measured 10 is located, and h as the distance from the observation port 11 to the plane where the object to be measured 10 is located. Then A' / B ≥ H / h. In this way, by matching the size of the first real image 15 and the size of the observation port 11, the measurement of reflectivity can be ensured. Preferably, H / h ≤ A' / B ≤ 2H / h.

[0077] See also Figure 2In some embodiments, the actual width C of the surface light source 12 in the horizontal direction and the width B of the observation port 11 in the horizontal direction may satisfy the following conditions:

[0078] According to the lens imaging formula:

[0079] (1 / u)+(1 / v)=1 / f,

[0080] It can be calculated that:

[0081] u / v=f / (vf),

[0082] The size of the first real image 15 of the surface light source 12 is greater than or equal to the size of the observation port 11 , so it can be concluded that the width C of the surface light source 12 in the horizontal direction satisfies:

[0083] C / B ≥ f / (vf);

[0084] Wherein, u is the object distance, i.e., the distance between the surface light source 12 and the first lens; v is the image distance, i.e., the distance between the first real image 15 of the surface light source 12 and the first lens; and f is the focal length of the first lens.

[0085] In some embodiments, the first lens transmits and focuses the detection light from the surface light source 12, so that the first real image 15 of the surface light source 12 formed below the first lens is positioned exactly at the opening of the observation port 11. In this case, u + v = L, where L is the installation height of the surface light source 12 above the observation port 11. However, in Example 1, the surface light source 12 cannot be directly installed at the opening of the observation port 11.

[0086] The first lens transmits and focuses the probe light from the surface light source 12, and forms a first real image 15 of the surface light source 12 below the first lens. This first real image 15 effectively replaces the surface light source 12 as the equivalent light-emitting surface of the probe light source. Therefore, the installation height of the surface light source 12 can be adjusted by appropriately setting the first lens.

[0087] Similarly, the intensity distribution of the incident probe light emitted from each location on the first real image 15 of the surface light source 12 is uniform and consistent within a solid angle normal to the plane where the first real image 15 resides. Half of the angle of this solid angle in any direction is defined as β', where β' is greater than or equal to the half-apex angle α' of the cone formed between the projection of the center of the observation port 11 on the plane where the object to be measured resides and the observation port 11. Furthermore, by disposing a first lens so that the first real image 15 of the surface light source 12 formed below the first lens is exactly at the aperture of the observation port 11, the plane where the observation port 11 resides serves as the new luminous surface formed by the first real image 15 of the surface light source 12. Incident light rays originating from this new luminous surface have a divergence angle greater than the aforementioned angle α. This not only allows the entire light beam from the surface light source 12 to be directed into the observation port 11, improving the utilization of the incident light, but also effectively ensures that the incident light rays still have a large divergence angle, thereby obtaining more outgoing probe light that can be emitted vertically above the observation port 11.

[0088] Example 2 is based on Example 1, and a first lens is added between the surface light source 12 and the observation port 11 to form a first real image 15 of the surface light source 12 to replace the surface light source 12 as the light-emitting surface of the detection light source in an equivalent sense. The light-emitting surface can be closer to the measured surface, so there is no need to use a large-sized surface light source 12, which can save costs and installation space. Moreover, by selecting a suitable first lens, the installation height of the surface light source 12 can be adjusted, thereby further expanding the use scenarios of the reflectivity optical measurement device.

[0089] Example 3

[0090] See also Figure 3 The difference between Example 3 and Example 2 is that the light emitting module described in this embodiment includes a surface light source 12, a second focusing imaging module 17, and a spectroscopic module 16. The spectroscopic module 16 can be arranged at the intersection of the incident detection light and the outgoing detection light. The second focusing imaging module 17 can be arranged between the surface light source 12 and the spectroscopic module 16. The surface light source 12 forms an image of the surface light source 12 at a position above the observation port 11 through the action of the second lens 17 and the spectroscopic module 16.

[0091] Specifically, the spectroscopic module 16 can be used to transmit the incident detection light from the surface light source 12 toward the observation port 11 and the object to be measured 10 below it, and to reflect the outgoing detection light reflected by the object to be measured 10 through the observation port 11 toward the light detection module 13. The second focusing imaging module 17 can be used to transmit and focus the incident detection light from the surface light source 12, and after transmission through the spectroscopic module 16, form a second real image 15' of the surface light source 12 at a position above the observation port 11. Alternatively, the spectroscopic module 16 can be used to reflect the incident detection light from the surface light source 12 toward the observation port 11 and the object to be measured 10 below it, and to transmit the outgoing detection light reflected by the object to be measured 10 through the observation port 11 toward the light detection module 13. The second focusing imaging module 17 can be used to transmit and focus the incident detection light from the surface light source 12, and after reflection through the spectroscopic module 16, form a second real image 15' of the surface light source 12 at a position above the observation port 11. Preferably, the light detection module 13 and the observation port 11 are arranged in a center-aligned manner.

[0092] In this embodiment, the second real image 15 ′ of the surface light source 12 constitutes the light-emitting surface of the incident detection light.

[0093] In some embodiments, the light detection module 13 can be positioned in the direction of either the transmitted or reflected beam of the spectrometer module 16. When the light detection module 13 is positioned in the direction of the transmitted beam of the spectrometer module 16, the light detection module 13 and the observation port 11 are centrally aligned. When the light detection module 13 is positioned in the direction of the reflected beam of the spectrometer module 16, the image formed by the light detection module 13 with respect to the spectrometer module 16 and the observation port 11 are centrally aligned.

[0094] In some embodiments, the second focusing imaging module 17 may include a second lens.

[0095] In some embodiments, the light splitting module 16 may include any one of a beam splitter and a semi-transparent and semi-reflective mirror.

[0096] Similarly, this embodiment actually utilizes the formed second real image 15' of the surface light source 12 to replace the surface light source 12 as the light-emitting surface of the detection light source in an equivalent sense. The width A" of the second real image 15' of the surface light source 12 in the horizontal direction and the width B of the observation port 11 in the horizontal direction meet certain conditions to ensure that no matter whether the installation is offset or the epitaxial wafer is warped, there must be incident detection light that can enter the observation port 11 and be reflected by the object to be measured 10 and then emitted through the observation port 11 to be detected by the light detection module 13. H is defined as the distance from the second real image 15' of the surface light source 12 to the plane where the object to be measured 10 is located, and h is the distance from the observation port 11 to the plane where the object to be measured 10 is located. Then A" / B ≥ H / h. In this way, by matching the size of the second real image 15' and the size of the observation port 11, the measurement of reflectivity can be ensured. Preferably, H / h ≤ A" / B ≤ 2H / h.

[0097] Similarly, the intensity distribution of the incident detection light emitted from each point on the second real image 15' of the surface light source 12 is uniform and consistent within a solid angle normal to the surface where the second real image 15' is located; half of the angle opened by the solid angle in any direction is defined as β", and β" is greater than or equal to the half-vertex angle α" of the cone formed between the projection of the center of the observation port 11 on the plane where the object to be measured is located and the observation port 11.

[0098] Example 3 is based on Example 2, and by adding a spectroscopic system (splitter), the setting position of the surface light source 12 can meet various installation requirements (for example, the surface light source 12 can be installed in a side position (relative to the orientation of the light detection module 13 installed above)).

[0099] The surface light source 12 and the light detection module 13 may also be located in positions that are not on the same plane, thereby expanding the installation scenarios.

[0100] The working principle of the present invention is described in detail below with reference to the accompanying drawings.

[0101] See also Figure 4 In the prior art, lasers are used as detection light sources. When, for example, a wafer to be measured warps during the growth process, no light signal will enter the detector because the laser emits parallel light, even if the laser's surface is infinite (i.e., the virtual image of the laser formed is infinite).

[0102] See also Figure 5In the present invention, a Lambertian radiator (such as an LED surface light source 12, etc., whose light beams at various locations have a uniform and consistent intensity distribution within a certain solid angle) is used as the detection light source. Since the light emitted by the surface light source 12 is non-parallel light, it has a certain divergence angle. In this way, even if the chip is tilted, although the detection light incident in the vertical direction will be deflected by the angle of the reflected light due to the tilt of the chip, resulting in it not being able to be emitted from the observation port 11 and detected, the detection light incident at other angles can still be emitted from the observation port 11 and thus detected by the detector.

[0103] In summary, the present invention uses a light-emitting module with a certain light-emitting surface to emit non-parallel light as incident probe light. By matching the relative dimensions of the probe light-emitting surface and the observation port 11, the incident probe light beam can completely cover the observation port 11. Therefore, regardless of the installation offset between the optical measurement device and the observation port on the reaction chamber, or the object to be measured is warped or tilted, the incident probe light emitted from the light-emitting surface can still enter the observation port and, after being reflected by the object to be measured, be emitted through the observation port and detected by the light detection module. Therefore, the optical path adjustment becomes relatively simple, and the probe light beam is not excessively restricted by the installation position, thereby achieving the purpose of simplifying the optical path and increasing reliability. Furthermore, by designing the solid angle range to ensure that the luminous intensity of the probe light is uniformly distributed and consistent, it can further ensure that the obtained reflectivity can be effectively used. The present invention is applicable to the reflectivity and temperature measurement of epitaxial wafers. In particular, for epitaxial wafers that are tilted due to warping, at least a portion of the probe light in the probe beam can still be emitted through the observation port 11 and effectively received by the light detection module 13. The device of the present invention can be highly integrated and can use a smaller-sized surface light source 12 to meet various detection conditions, and can make the setting position of the surface light source 12 meet various installation requirements, thereby broadening the application scenarios of the present invention.

[0104] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A reflectivity optical measuring device, characterized in that: It is arranged outside the reaction chamber and includes: a light emitting module and a light detecting module; The light emitting module is configured to emit incident detection light, the light emitting module comprising a light emitting surface for emitting the incident detection light, the incident detection light being non-parallel light, at least a portion of the incident detection light being projected onto a surface of the object to be detected in the reaction chamber through an observation port on the reaction chamber, and being reflected by the surface; The light detection module is used to receive the outgoing detection light reflected by the measured surface and emitted through the observation port; The intensity of the incident detection light emitted at each location on the light-emitting surface within the solid angle normal to the light-emitting surface is uniformly distributed, and the intensity distribution at each location within the solid angle is consistent; half of the angle of the solid angle in any direction is defined as β, and β is greater than or equal to the half-apex angle α of the cone formed between the projection of the center of the observation port on the plane where the object to be measured is located and the observation port; The size A of the light-emitting surface and the size B of the observation port satisfy the following conditions: A / B≥H / h Wherein, H is the distance from the light emitting surface to the plane where the object to be measured is located, and h is the distance from the observation port to the plane where the object to be measured is located.

2. The reflectivity optical measuring device according to claim 1, wherein The dimension A of the light emitting surface and the dimension B of the observation port satisfy the following: H / h≤A / B≤2H / h.

3. The reflectivity optical measuring device according to claim 1, wherein The light emitting module includes a surface light source, which constitutes the light-emitting surface of the incident detection light. The surface light source is arranged facing the observation port. A receiving hole is provided on the surface of the surface light source, and the light detection module receives the outgoing detection light reflected by the measured surface and emitted through the observation port through the receiving hole. The receiving hole, the light detection module and the observation port are arranged in a centrally aligned manner.

4. The reflectivity optical measuring device according to claim 1, wherein The light emitting module includes: a surface light source and a first lens, The surface light source emits the incident detection light, The first lens is located between the surface light source and the observation port, and is used to transmit and focus the incident detection light from the surface light source, and form an image of the surface light source at a position between the first lens and the observation port, and the image of the surface light source constitutes the light-emitting surface of the incident detection light. The surface light source is provided with a receiving hole penetrating the surface, and the light detection module receives the outgoing detection light reflected by the measured surface and emitted through the observation port through the receiving hole, wherein the receiving hole, the light detection module and the observation port are arranged in a centrally aligned manner.

5. The reflectivity optical measuring device according to claim 4, characterized in that: The image of the surface light source is located at the position of the observation port.

6. The reflectivity optical measuring device according to claim 4, characterized in that: The size C of the surface light source and the size B of the observation port satisfy the following conditions: C / B≥f / (vf) Wherein, f is the focal length of the first lens, and v is the distance from the image of the surface light source to the first lens.

7. The reflectivity optical measuring device according to claim 1, wherein The light emitting module includes: a surface light source, a second lens and a light splitting module. The surface light source emits the incident detection light, The light splitting module is used to transmit / reflect the incident detection light from the surface light source toward the observation port, and to reflect / transmit the outgoing detection light reflected by the object to be measured and emitted through the observation port toward the light detection module accordingly. The second lens is used to transmit and focus the incident detection light from the surface light source. The surface light source forms an image of the surface light source at a position above the observation port through the action of the second lens and the light splitting module. The image of the surface light source constitutes the light-emitting surface of the incident detection light. The light detection module and the observation port are arranged in a centrally aligned manner, or the image formed by the light detection module with respect to the light splitting module and the observation port are arranged in a centrally aligned manner.

8. The reflectivity optical measuring device according to any one of claims 3, 4 or 7, characterized in that: The surface light source includes an LED surface light source, or the surface light source is formed by a point light source or laser irradiating frosted glass, or the surface light source includes a light source with Lambertian radiator properties.

9. The reflectivity optical measuring device according to claim 1, wherein: The reflectivity optical measurement device also includes a control module, and the light detection module includes a light intensity detector. The light intensity detector detects the light intensity signal of the outgoing detection light and transmits the light intensity signal to the control module. The control module calculates the reflectivity of the object to be measured based on the intensity of the incident detection light and the intensity of the outgoing detection light.

10. The reflectivity optical measuring device according to claim 1, wherein The reaction chamber is a MOCVD reaction chamber.

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