Light source for semiconductor device measurement and semiconductor device measurement system

Abstract

The present invention provides a light source for measuring semiconductor devices and a measuring system for semiconductor devices. The light source for measuring semiconductor devices includes a light bulb, a first reflector, a focusing assembly and an optical fiber. The light bulb is filled with xenon gas and includes a cathode and an anode. When current passes between the cathode and the anode, the xenon gas at the cathode forms a plasma to radiate light outward through a light-emitting point. The first reflector is arranged on the first side of the light bulb, and is used to reflect and focus the first light emitted from the light-emitting point to the first side back to the light-emitting point. The focusing assembly is arranged on the second side of the light bulb and includes a second reflector and a third reflector. The second reflector is used to collimate the second light emitted from the light-emitting point to the second side and the first light reflected from the first reflector back to the light-emitting point together to the third reflector, and then the third reflector focuses both together to the receiving end of an optical fiber. The optical fiber includes a receiving end and an output end, and is used to transmit the light obtained by the receiving end to the output end.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor defect detection, and in particular to a light source for semiconductor device measurement, and a semiconductor device measurement system. Background Art

[0002] In the field of semiconductor quantity detection, the width of the light source band will limit the range of semiconductor film thickness that the equipment can accurately measure. Measuring the film thickness from sub-nanometer to micron level requires the use of light from ultraviolet to near-infrared bands. Common ultra-wideband light sources that can cover the ultraviolet to near-infrared bands include xenon lamps, mercury lamps, halogen lamps, etc. Xenon lamps are widely used in the semiconductor field due to their wide-band continuous spectrum and high luminous efficiency. However, the single-wavelength light power output of existing xenon lamps is low, and the output power of ultraviolet light is even lower. After the emitted light beam passes through multiple optical elements, the effective output power will be greatly attenuated, resulting in low measurement curve fitting accuracy, inaccurate measurement results, and even directly causing the equipment to be unable to measure sub-nanometer film thickness. In addition, the life of the xenon lamp bulb is short, and the bulb needs to be replaced after long-term use. After the current xenon lamp bulb is replaced, the optical path needs to be fine-tuned, which is difficult to operate. In addition, although the solution of using multiple lens groups to couple can provide an ultra-wide-band light source, it is difficult to optimize the chromatic aberration to a very small level because there are very few lens materials that can transmit the ultraviolet to infrared bands, and it requires the use of multiple pieces in combination, which greatly increases the cost and occupied space.

[0003] In order to overcome the above-mentioned defects of the prior art, there is an urgent need in the art for an improved light source for semiconductor device measurement, which can eliminate the need for re-fine-tuning the light path, reduce the difficulty of replacing a new bulb, and take into account the effective output power of the light source and the miniaturization design of the light source. Summary of the invention

[0004] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or decisive elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0005] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides a light source for semiconductor device measurement and a semiconductor device measurement system, which can avoid the absorption of light beam energy by the lens by adopting a fully reflective optical component, thereby improving the effective output power of the light source. Secondly, the light source and the back-end detection component can be decoupled by adopting the form of optical fiber output, thereby eliminating the need to re-fine-tune the optical path and reducing the difficulty of replacing a new bulb. In addition, with regard to the form of optical fiber output, on the one hand, a first reflector is used to recover the scattered first light, and on the other hand, a common focusing component is configured to synchronously lead out the reflected first light and the actively emitted second light, thereby taking into account both the effective output power of the light source and the miniaturized design of the light source.

[0006] Specifically, the light source for semiconductor device measurement provided according to the first aspect of the present invention comprises a bulb, a first reflector, a focusing assembly and an optical fiber. The bulb is filled with xenon gas and comprises a cathode and an anode. When current passes between the cathode and the anode, the xenon gas at the cathode forms plasma to radiate light outward through a light-emitting point. The first reflector is arranged on the first side of the bulb, and is used to reflect the first light emitted from the light-emitting point to the first side and focus it back to the light-emitting point. The focusing assembly is arranged on the second side of the bulb, and comprises a second reflector and a third reflector. The second reflector is used to collimate the second light emitted from the light-emitting point to the second side and the first light reflected from the first reflector back to the light-emitting point together to the third reflector, and then the third reflector focuses both together to the receiving end of an optical fiber. The optical fiber comprises the receiving end and an output end, and is used to transmit the light obtained by the receiving end to the output end.

[0007] Further, in some embodiments of the present invention, the first reflector is a spherical reflector. The light-emitting point is located at twice the focal length of the first reflector, so that the first reflector reflects the first light and focuses it back to the light-emitting point. The second reflector and the third reflector are both parabolic mirrors. The light-emitting point is located at one times the focal length of the second reflector, so that the second reflector can collimate the second light and the first light together to the third reflector. The receiving end of the optical fiber is located at one times the focal length of the third reflector, so that the third reflector can focus the collimated first light and the second light together to the receiving end of the optical fiber.

[0008] Further, in some embodiments of the present invention, the first reflector has an effective aperture of 45.72 mm or more, maintains a spatial angle of 0.586π or more with the light-emitting point, and has a numerical aperture of 0.45 or more. And / or the second reflector has an effective aperture of 45.72 mm or more, maintains a spatial angle of 0.586π or more with the light-emitting point, and has an object-side numerical aperture of 0.45 or more. And / or the third reflector has an effective aperture of 45.72 mm or more, and has an image-side numerical aperture of 0.225 or less.

[0009] Furthermore, in some embodiments of the present invention, the receiving end of the optical fiber and the light emitting point are located on the same side of the focusing assembly. The focusing direction of the second reflector is the same as that of the third reflector.

[0010] Further, in some embodiments of the present invention, the light bulb and the first reflector constitute a first module of the light source. The first reflector supports multi-degree-of-freedom adjustment in the first module to adjust the light bulb to twice its focal length. The focusing assembly and the optical fiber constitute a second module of the light source. The receiving end of the optical fiber supports multi-degree-of-freedom adjustment in the second module to adjust itself to one focal length of the third reflector.

[0011] Furthermore, in some embodiments of the present invention, the window material of the bulb emitting the first light and / or the second light is made of fused silica glass. And / or the reflection surface of the first reflector, the second reflector and / or the third reflector is coated with an ultraviolet enhancement film. And / or the optical fiber is a UV optical fiber.

[0012] Furthermore, in some embodiments of the present invention, the light source further includes a magnetic member. The magnetic member is located outside the bulb and on the side of the cathode facing the anode, and is used to migrate the light-emitting point from the cathode to between the cathode and the anode. The first reflector is placed at a preset tilt angle to reflect and focus the first light back to the light-emitting point between the cathode and the anode.

[0013] Furthermore, in some embodiments of the present invention, the light source further includes a cooling module for reducing the temperature inside the bulb to extend the working life of the bulb.

[0014] In addition, the semiconductor device measurement system provided according to the second aspect of the present invention comprises the first light source and the detection module for semiconductor device measurement provided according to the first aspect of the present invention. The detection module is connected to the optical fiber output end of the first light source to obtain the detection light provided by the first light source, and uses the detection light to measure the semiconductor device.

[0015] Furthermore, in some embodiments of the present invention, the detection module includes a wavelength selection unit, an optical unit and a spectrometer. The wavelength selection unit is used to filter the detection light corresponding to the measurement function from the detection light provided by the light source. The optical unit includes a first spectroscope and a second spectroscope. The first spectroscope is used to first transmit the detection light to a high-power objective lens and a low-power objective lens, so as to uniformly illuminate the sample to be tested on the object side through the high-power objective lens or the low-power objective lens, and then transmit the first reflected light generated by the sample to be tested to the second spectroscope on the image side, so as to transmit the first reflected light to the spectrometer at the rear end through the pinhole mirror. The spectrometer is used to collect spectral information of the first reflected light provided by the second spectroscope to indicate the average film thickness in the first area of ​​the surface of the sample to be tested that is larger than a preset size.

[0016] Furthermore, in some embodiments of the present invention, the detection module also includes a second light source and a camera. The second light source is coupled to the front end of the first beam splitter via a third beam splitter, and is used to provide illumination light for imaging the sample to be tested, wherein the illumination light first reaches the high-power objective lens and the low-power objective lens via the first beam splitter, so as to uniformly illuminate the sample to be tested on the object side via the high-power objective lens or the low-power objective lens, and then transmits the second reflected light generated by the sample to be tested to the second beam splitter on the image side, so as to transmit the second reflected light to the camera at the rear end via the pinhole mirror. The camera is used to generate a corresponding sample image based on the second reflected light transmitted to its detection surface, so as to indicate the film thickness and / or microstructure in the second area of ​​the surface of the sample to be tested that is less than or equal to the preset size.

[0017] Furthermore, in some embodiments of the present invention, the detection module also includes an image sensor, which is coupled to the rear end of the first beam splitter via a fourth beam splitter, and is used to collect images output by the high-power objective lens and / or the low-power objective lens to determine the focal plane position of the high-power objective lens and / or the low-power objective lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0019] Figure 1 A schematic structural diagram of a semiconductor device measurement system provided according to some embodiments of the present invention is shown.

[0020] Figure 2 A schematic diagram of the system structure of a light source for semiconductor device measurement provided according to some embodiments of the present invention is shown.

[0021] Figure 3 A schematic structural diagram of a light bulb provided according to some embodiments of the present invention is shown.

[0022] Figure 4 A schematic structural diagram of a light focusing assembly provided according to some embodiments of the present invention is shown.

[0023] Figure 5 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0024] Figure 6 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0025] Figure 7 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0026] Figure 8 A schematic structural diagram of a detection module provided according to some embodiments of the present invention is shown.

[0027] Fig. 9 A schematic diagram of the irradiance of the full spectrum of a light bulb provided according to some embodiments of the present invention is shown.

[0028] Fig.10 A schematic diagram of a spherical receiving surface for arc-luminous light provided according to some embodiments of the present invention is shown.

[0029] Fig.11 A schematic diagram of the spectrum output by a light source provided according to some embodiments of the present invention is shown. DETAILED DESCRIPTION

[0030] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0033] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0034] As mentioned above, the single-wavelength optical power output by existing xenon lamps is low, and the output power of ultraviolet light is even lower. After the emitted light beam passes through multiple optical elements, the effective output power will be greatly attenuated, resulting in low measurement curve fitting accuracy, inaccurate measurement results, and even directly causing the equipment to be unable to measure sub-nanometer film thickness. In addition, the life of the xenon lamp bulb is short, and the bulb needs to be replaced after long-term use. The current xenon lamp needs to fine-tune the optical path after replacing the bulb, which is difficult to operate. In addition, although the solution of using multiple lens groups to couple can provide an ultra-wideband light source, it is difficult to optimize the chromatic aberration to a very small level because there are very few lens materials that can pass through the ultraviolet to infrared bands, and it requires the use of multiple pieces in combination, which greatly increases the cost and occupied space.

[0035] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides a light source for semiconductor device measurement and a semiconductor device measurement system, which can avoid the absorption of light beam energy by the lens by adopting a fully reflective optical component, thereby improving the effective output power of the light source. Secondly, the light source and the back-end detection component can be decoupled by adopting the form of optical fiber output, thereby eliminating the need to re-fine-tune the optical path and reducing the difficulty of replacing a new bulb. In addition, with regard to the form of optical fiber output, on the one hand, a first reflector is used to recover the scattered first light, and on the other hand, a common focusing component is configured to synchronously lead out the reflected first light and the actively emitted second light, thereby taking into account both the effective output power of the light source and the miniaturized design of the light source.

[0036] In some non-limiting embodiments, the semiconductor device measurement system provided in the second aspect of the present invention includes the light source and detection module for semiconductor device measurement provided in the first aspect of the present invention.

[0037] Please refer to Figure 1 . Figure 1 A schematic structural diagram of a semiconductor device measurement system provided according to some embodiments of the present invention is shown.

[0038] exist Figure 1 In the illustrated embodiment, the detection module 40 is connected to the optical fiber output end of the light source 10 to obtain the detection light provided by the light source 10 and utilize the detection light to measure the semiconductor device.

[0039] Please refer to further Figure 2 to Figure 4 . Figure 2 A schematic diagram of the system structure of a light source for semiconductor device measurement provided according to some embodiments of the present invention is shown. Figure 3 A schematic structural diagram of a light bulb provided according to some embodiments of the present invention is shown. Figure 4 A schematic structural diagram of a light focusing assembly provided according to some embodiments of the present invention is shown.

[0040] exist Figure 2 to Figure 4 In the illustrated embodiment, the light source 10 for semiconductor device measurement provided by the first aspect of the present invention includes a bulb 11 , a first reflector 12 , a focusing component 13 and an optical fiber 14 .

[0041] Specifically, Figure 3 As shown, the bulb 11 is filled with xenon gas and includes a cathode 111 and an anode 112. The xenon gas at the cathode 111 forms plasma when current passes between the cathode 111 and the anode 112, so as to radiate light outward through a luminous point. Here, the present invention can select a bulb with a power of 75W and an arc length of 1mm, and can also be replaced with a bulb of other power.

[0042] like Figure 2 and Figure 4 As shown, the first reflector 12 is disposed on the first side (e.g., the upper side) of the bulb 11, and is used to reflect the first light emitted from the light-emitting point to the first side and focus it back to the light-emitting point. The focusing assembly 13 is disposed on the second side (e.g., the lower side) of the bulb, and includes a second reflector 131 and a third reflector 132. Here, the second reflector 131 is used to collimate the second light emitted from the light-emitting point to the second side, and the first light reflected from the first reflector 12 back to the light-emitting point, to the third reflector 132, and then the third reflector 132 focuses both of them to a receiving end 141 of an optical fiber 14. The optical fiber 14 includes a receiving end 141 and an output end 142, and is used to transmit the light obtained by the receiving end 141 to the output end 142.

[0043] Further, in some preferred embodiments, the first reflector 12 is a spherical reflector. Here, the light-emitting point is located at twice the focal length of the first reflector 12, so that the first reflector 12 reflects the first light and focuses it back to the light-emitting point. The second reflector 131 and the third reflector 132 are both parabolic mirrors. Here, the light-emitting point is located at one focal length of the second reflector 131, so that the second reflector 131 can collimate the second light and the first light together to the third reflector 132, and the receiving end of the optical fiber 14 is located at one focal length of the third reflector 132, so that the third reflector 132 can focus the collimated first light and the second light together to the receiving end 141 of the optical fiber 14.

[0044] In this way, with respect to the design of a shared focusing component, the above-mentioned light source 10 provided in the first aspect of the present invention can focus the scattered first light back to the light-emitting point via a spherical reflector at twice the focal length, so that the rear-end focusing component 13 can accurately focus the reflected first light and the actively emitted second light onto the receiving end 141 of the optical fiber 14, thereby improving the effective output power of the light source 10.

[0045] Furthermore, in Figure 4 In the embodiment shown, the first reflector 12 has an effective aperture of 45.72 mm or more, which is used to reduce the energy density of the light beam received by the parabolic mirror surface, so as to reduce the risk of film shedding or aging, thereby improving the stability of the energy output by the light source 10. The first reflector 12 maintains a spatial angle of 0.586π or more with the light-emitting point. The first reflector 12 has a numerical aperture of 0.45 or more (for example: NA = 0.5), which is used to receive more light beam energy to increase the effective output power of the light source 10.

[0046] Here, the effective aperture is the coating area that meets the design requirements, which is generally 90% of the full aperture. The numerical aperture NA can be calculated from the refractive index n of the medium between the object and the parabolic mirror and the aperture angle θ of the parabolic mirror:

[0047] NA=n×sinθ / 2

[0048] In addition, Figure 4 In the embodiment shown, the second reflector 131 has an effective aperture of 45.72 mm or more, which is used to reduce the energy density of the light beam received by the parabolic mirror surface to reduce the risk of film shedding or aging, thereby improving the stability of the energy output by the light source 10. The second reflector 131 maintains a spatial angle of 0.586π or more with the light-emitting point. The second reflector 131 has an object-side numerical aperture of 0.45 or more (for example: NA = 0.5), which is used to receive more light beam energy to increase the effective output power of the light source 10.

[0049] In addition, Figure 4 In the illustrated embodiment, the third reflector 132 has an effective aperture of 45.72 mm or more, which is used to reduce the energy density of the light beam received by the parabolic mirror surface, so as to reduce the risk of film shedding or aging, thereby improving the stability of the energy output by the light source 10. The third reflector 132 has an image-side numerical aperture of less than 0.225, which can improve the coupling efficiency of the optical fiber, so as to improve the effective output power of the light source 10.

[0050] Compared with the focusing assembly of the front parabola with a small effective aperture or a small object-side numerical aperture, which can only collect a part of the light beam energy, the focusing assembly of the rear parabola with a small effective aperture has the problem that the output energy is too concentrated, and the focusing assembly of the rear parabola with a large image-side numerical aperture has the problem of low fiber coupling efficiency, the focusing assembly composed of the second reflector 131 with a large effective aperture and a large object-side numerical aperture, and the third reflector 132 with a large effective aperture and a small image-side numerical aperture adopted in the present invention can not only receive more light beam energy and improve the coupling efficiency of the optical fiber to improve the effective output power of the light source 10, but also reduce the energy density of the light beam received on the surface of the parabola to reduce the risk of film shedding or aging, thereby improving the stability of the output energy of the light source 10.

[0051] In addition, please refer to Figure 4 and Figure 5 . Figure 5 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0052] Compared to Figure 5 The reference example shown uses two parabolic mirrors with different focusing directions to collect the light provided by the bulb 11. Figure 4 The receiving end 141 of the optical fiber 14 and the light emitting point are located on the same side of the focusing assembly 13, and the focusing directions of the second reflector 131 and the third reflector 132 are the same. This light collection structure with co-focusing can effectively improve the uniformity of the focused light spot, thereby improving the measurement accuracy of semiconductor devices.

[0053] In addition, please refer to Figure 4 and Figure 6 . Figure 6 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0054] Compared to Figure 6 The problem of using an ellipsoidal mirror for high coupling efficiency focusing is that the processing is difficult and the cost is high. Figure 4 The focusing assembly composed of two parabolic mirrors has a regular curve formula, so the processing difficulty and processing cost are lower.

[0055] In addition, please refer to Figure 4 and Figure 7 . Figure 7 A schematic structural diagram of a focusing assembly provided according to a reference example is shown.

[0056] Compared to Figure 7 The problem that there is no light in the middle of the illumination area of ​​the focusing assembly shown in the figure, which uses two or more ellipsoidal mirrors to simultaneously focus the light outputted from the bulb in different directions, Figure 4 The central area of ​​the focusing assembly, which uses two parabolic mirrors to collimate and focus the detection light in sequence, is brighter and is therefore more suitable for measuring semiconductor devices in specific micro areas.

[0057] In addition, Figure 4 In the illustrated embodiment, the above-mentioned bulb 11 and the first reflector 12 may constitute the first module 21 of the light source 10. Here, the first reflector 12 supports multi-degree-of-freedom adjustment along the XYZ direction in the first module 31 to adjust the bulb 11 to twice its focal length. The focusing assembly 13 and the optical fiber 14 may constitute the second module 22 of the light source. Here, the receiving end 141 of the optical fiber 14 supports multi-degree-of-freedom adjustment along the XYZ direction in the second module 22 to adjust itself to one focal length of the third reflector 132, at which time the energy outputted from the output end of the optical fiber is maximum.

[0058] Here, the light source 10 provided in the first aspect of the present invention can adopt a modular design to support offline pre-assembly and replacement of spare light sources. In this way, when the life of the light bulb 11 is exhausted, it is only necessary to disassemble, replace, and lock the first module 21 to easily and quickly replace the light bulb, thereby improving the inspection efficiency of semiconductor devices.

[0059] In addition, Figure 3 In the embodiment shown, the window 113 of the bulb 11 that emits the first light and / or the second light is made of fused quartz glass, which can transmit light in the ultraviolet to infrared bands. Figure 3In the illustrated embodiment, an ultraviolet enhancement film is coated on the reflective surface of the first reflector 12, the second reflector 131 and / or the third reflector 132. The optical fiber 14 is a UV optical fiber.

[0060] Thus, in order to address the problem of weak ultraviolet output capacity of traditional xenon lamps, the light source 10 provided in the first aspect of the present invention is provided with a specific optical design for reducing light loss in the ultraviolet band, so as to enhance the output capacity of the light source 10 in the ultraviolet band, thereby achieving output in a wide spectral band of 350nm to 700nm.

[0061] In addition, Figure 2 In the illustrated embodiment, the light source 10 provided by the first aspect of the present invention preferably further includes a magnetic member 15. Here, the magnetic member 15 is located outside the bulb 11 and on the side of the cathode 111 facing the anode 112, and is used to migrate the light emitting point from the cathode 111 to between the cathode 111 and the anode 112. The first reflector 12 is placed at a preset tilt angle (e.g., 0.1°) to reflect and focus the first light back to the light emitting point between the cathode 111 and the anode 112.

[0062] In this way, the light source 10 provided in the first aspect of the present invention can ensure the stability of the output light power, and make the light spot focused by the reflector avoid the electrode position, so as to extend the service life of the cathode 111.

[0063] In addition, Figure 2 In the illustrated embodiment, the light source 10 provided in the first aspect of the present invention preferably further comprises a cooling module 16. Here, the cooling module 16 is used to reduce the temperature inside the bulb 11 to extend the service life of the bulb 11.

[0064] In addition, Figure 2 In the illustrated embodiment, the light source 10 provided in the first aspect of the present invention may further optionally include a power supply 17 and a trigger 18 for ionizing the xenon gas between the cathode 111 and the anode 112 of the bulb 11 to form plasma.

[0065] In addition, please refer to Figure 8 . Figure 8 A schematic structural diagram of a detection module provided according to some embodiments of the present invention is shown.

[0066] exist Figure 8In the embodiment shown, the detection module 40 includes a wavelength selection unit, an optical unit and a spectrometer 420. Here, the wavelength selection unit is used to filter the detection light corresponding to the measurement function from the detection light provided by the light source 10. The wavelength selection unit includes a first parabolic mirror 401, a color wheel 402, a second parabolic mirror 403, a pinhole 421 and a third parabolic mirror 404. The optical unit includes a first beam splitter 408 and a second beam splitter. The second beam splitter assembly includes a tube lens 415, a pinhole mirror 418, a relay mirror 416 and a relay mirror 417. The first beam splitter 408 is used to first transmit the detection light to a high-power objective lens 409 and a low-power objective lens 410, so as to transmit the detection light to the low-power objective lens 410 through the high-power objective lens 409 or through the reflector 411 to uniformly illuminate the sample 422 to be tested on the object side, and then transmit the first reflected light generated by the sample 422 to the second beam splitter on the image side, so as to transmit the first reflected light to the spectrometer 420 at the rear end through its pinhole mirror 418. The spectrometer 420 is used to collect the spectral information of the first reflected light provided by the second beam splitter to indicate the average film thickness in the first area larger than the preset size on the surface of the sample 422 to be tested.

[0067] In addition, Figure 8 In the illustrated embodiment, the detection module 40 may also be preferably configured with an illumination light source and a camera 419. Here, the illumination light source includes an LED light source 405 and a collimator 406. The LED light source 405 provides white light with a wavelength range of 230nm to 1000nm. The illumination light source is coupled to the front end of the first beam splitter 408 via a third beam splitter 407, and is used to provide illumination light for imaging the sample to be tested 422. Afterwards, the illumination light first reaches the high-power objective lens 409 and the low-power objective lens 410 via the first beam splitter 408, so as to uniformly illuminate the sample to be tested 422 on the object side through the high-power objective lens 409 or the low-power objective lens 410, and then transmits the second reflected light generated by the sample to be tested 422 to the second beam splitter on the image side, so as to transmit the second reflected light to the rear camera 419 via its pinhole mirror 418. The camera 419 is used to generate a corresponding sample image according to the second reflected light transmitted to its detection surface to indicate the film thickness and / or microstructure in a second area of ​​the surface of the sample to be tested that is less than or equal to a preset size.

[0068] In addition, in some embodiments of the present invention, in view of the need for an autofocus function, the detection module 40 may also preferably include a moving stage (not shown) and an image sensor 423. The moving stage is used to carry and carry the sample 422 to be tested to move laterally between a first position below the high-power objective lens 409 and a second position below the low-power objective lens 410, and to move longitudinally in a vertical direction close to or away from the high-power objective lens 409 and the low-power objective lens 410. The image sensor 423 is coupled to the rear end of the first beam splitter 408 via a fourth beam splitter assembly, and is used to collect images output by the high-power objective lens 409 and / or the low-power objective lens 410 to determine the focal plane position of the high-power objective lens 409 and / or the low-power objective lens 410. Here, the fourth beam splitter assembly includes a beam splitter 412, a cylindrical mirror 413, and a cylindrical mirror 414.

[0069] In this way, the detection module 40 can simultaneously set the spectrometer 420 and the camera 419 to adapt to the measurement requirements of the average film thickness of the first area larger than the preset size, the film thickness and / or microstructure in the second area less than or equal to the preset size, and the functional requirement of automatic focusing on the sample to be measured, so as to achieve "one-stop" measurement of various semiconductor parameters, thereby effectively reducing the economic cost of semiconductor measurement and improving the efficiency of semiconductor measurement.

[0070] Specifically, during the measurement process, the detection module 40 may first obtain a control instruction input by the user. In some embodiments, in response to a first control instruction indicating that the area to be measured is larger than a preset size (e.g., 30 μm), the detection module 40 may determine that the area to be measured is the first area, and enter the first detection mode of the large-size area, thereby first turning on the light source 10, and providing a wide spectrum of light to the surface of the sample to be measured 422 via the wavelength selection unit, and then determining the average film thickness in the first area based on the spectral information collected by the spectrometer 420.

[0071] In other embodiments, in response to the first control instruction indicating that the area to be tested is less than or equal to a preset size (e.g., 30 μm), the detection module 40 may determine that the area to be tested is the second area and enter the second mode of the small-size area, thereby turning off the light source 10 and turning on the LED light source 405 to provide a variety of narrow-band illumination lights with different central wavelengths to the surface of the sample to be tested 422 in a time-sharing manner. At the same time, the detection module 40 may collect sample images of the corresponding second area under each narrow-band illumination light through the camera 419.

[0072] Afterwards, the detection module 40 can analyze each sample image to determine the relative light intensity value and / or relative reflectivity value of each sample image, and fit the relative light intensity curve and / or relative reflectivity curve of the second region with respect to each central wavelength accordingly. Afterwards, the detection module 40 can input the relative light intensity curve and / or relative reflectivity curve obtained by fitting into the pre-trained regression analysis model, and perform regression analysis on the relative light intensity curve and / or relative reflectivity curve through the regression analysis model to determine the film thickness on the surface of the second region.

[0073] Furthermore, the above-mentioned regression analysis model can be obtained by training multiple groups of sample data of relative light intensity curves and / or relative reflectivity curves of multiple standard samples with known film thicknesses at multiple different central wavelengths. Specifically, in the process of training the above-mentioned regression analysis model, the technician can first obtain multiple groups of sample data of relative light intensity curves and / or relative reflectivity curves of multiple standard samples with known film thicknesses at multiple different central wavelengths, and construct a regression analysis model based on the Levenberg–Marquardt algorithm. Afterwards, the detection module 40 can input the relative light intensity curves and / or relative reflectivity curves of each group of sample data into the above-mentioned regression analysis model, and correct the learning parameters of the regression analysis model according to the corresponding film thickness, so as to obtain a regression analysis model that has been trained.

[0074] Optionally, in other embodiments, in response to obtaining the second control instruction indicating the detection of the defect size and / or the trace width on the sample to be tested, the detection module 40 may also control the LED light source 405 to output a plurality of narrow-band illumination lights of different central wavelengths in time division, and control the camera 419 to respectively collect the third sample images illuminated by each narrow-band illumination light. Afterwards, the detection module 40 may also use the pre-trained image recognition model and / or template comparison model to respectively perform image feature extraction and target recognition on the third sample images illuminated by each narrow-band illumination light, so as to respectively determine the corresponding recognition results, and average the recognition results of each third sample image to determine the defect size and / or trace width on the sample to be tested 422.

[0075] Furthermore, when detecting the defect size and / or trace width on the sample to be tested, the detection module 40 can preferably first use the low-power objective lens 410 to perform preliminary defect detection / preliminary line width detection, and then use the high-power objective lens 409 to review or verify after the detection result exceeds the preset threshold, so as to further improve the detection accuracy of the defect size and / or trace width.

[0076] Optionally, in other embodiments, in response to obtaining a second control instruction instructing to execute an autofocus function, the detection module 40 can also control the moving stage to first move the marking point or the area to be tested of the sample to be tested 422 to the second field of view of the low-magnification objective lens 410, and then move the sample to be tested 422 up and down, and control the image sensor 423 to capture a first sample image of the sample to be tested 422.

[0077] Afterwards, in response to the first sample image reaching the state of optimal contrast, the detection module 40 can control the moving stage to first keep the up and down position of the sample to be tested 422 unchanged, and move the marking point or the area to be tested of the sample to be tested to the first field of view of the high-power objective lens 409, and then move the sample to be tested up and down, and control the image sensor 423 to collect the second sample image of the sample to be tested, so as to achieve the state of optimal contrast in the second sample image, or the sum of the grayscale values ​​of the second sample image reaches a peak value, and it is determined that the focus on the sample to be tested is completed.

[0078] Furthermore, in some embodiments, since the spectrometer 420 has a lower amount of light intensity calculation data and a faster light intensity calculation response, in the process of moving the sample to be tested up and down, the detection module 40 can first control the spectrometer 420 to detect the intensity of the reflected light, and then after the intensity of the reflected light collected by the spectrometer 420 reaches a peak value, switch the camera 419 to collect the first sample image or the second sample image of the sample to be tested, and use the contrast of the charge-coupled device (CCD) of the image sensor 423 or the total grayscale of the image as the focal plane criterion to determine the optimal contrast position of the sample to be tested, thereby improving the autofocus efficiency of the detection module 40.

[0079] Preferably, in other embodiments, the technician can also calibrate the distance between the peak position of the light intensity of the spectrometer 420 and the best contrast position or the peak position of the total gray value of the image sensor 423 using a reference piece with known characteristics, and pre-store it in the detection module 40. In this way, in the process of moving the sample 422 to be tested up and down, in response to the light intensity of the reflected light reaching a peak value, the detection module can directly determine the focus position of the sample 422 to be tested based on the current position and the distance, thereby further improving the automatic focusing efficiency of the detection module 40.

[0080] In this way, the above-mentioned detection module 40 can perform large-area film thickness measurement, small-area film thickness measurement and microstructure detection respectively, so as to realize "one-stop" measurement of various semiconductor parameters, thereby effectively reducing the economic cost of semiconductor measurement and improving the efficiency of semiconductor measurement.

[0081] Please refer to Figures 9 to 11 . Fig. 9A schematic diagram of the irradiance of the full spectrum of a light bulb provided according to some embodiments of the present invention is shown. Fig.10 A schematic diagram of a spherical receiving surface for arc-luminous light provided according to some embodiments of the present invention is shown. Fig.11 A schematic diagram of the spectrum output by a light source provided according to some embodiments of the present invention is shown.

[0082] like Fig. 9 and Fig.10 As shown, xenon lamps of different powers correspond to light irradiances of different wavelengths at a distance of 50 cm. The surface area of ​​a sphere with a radius R of 50 cm can be regarded as the light beam receiving area:

[0083] S=4π·R 2

[0084] In this way, the luminous flux emitted by the corresponding bulb arc is approximately:

[0085] Φ(λ)=E(λ)·S·△λ

[0086] Among them, Φ(λ) is the light flux of different wavelengths, S is the light beam receiving area, and △λ is the spectral bandwidth.

[0087] From this, the irradiance of the light source in different bands can be calculated:

[0088]

[0089] like Fig.11 As shown, since the energy of the xenon lamp bulb in the ultraviolet band is weak, and the traditional xenon lamp absorbs the energy in the ultraviolet band, the output light energy in the ultraviolet band is about 0, while the light source provided by the first aspect of the present invention has less loss of light energy in the ultraviolet band and a reflectivity of up to 90%. In this way, the light source provided by the first aspect of the present invention improves the original light utilization efficiency by 100%, especially the energy in the ultraviolet band is significantly improved, the light collection ratio of the entire light source is 0.3, and the total output light irradiation power is doubled compared to the traditional xenon lamp. Therefore, after the above light source is used in the film thickness measurement equipment, the film thickness from sub-nanometer to micrometer level can be measured.

[0090] In summary, the above-mentioned light source for semiconductor device measurement and the semiconductor device measurement system provided by the present invention can avoid the absorption of light beam energy by the lens by adopting a fully reflective optical component, thereby improving the effective output power of the light source. In addition, by adopting the form of optical fiber output to achieve decoupling of the light source and the back-end detection component, the present invention can eliminate the need to re-fine-tune the light path after replacing the light source, thereby reducing the difficulty of replacing a new bulb. In addition, with regard to the form of optical fiber output, the present invention, on the one hand, uses a first reflector to recover the scattered first light, and on the other hand, configures a common focusing component to synchronously lead out the reflected first light and the actively emitted second light, thereby taking into account both the effective output power of the light source and the miniaturized design of the light source.

[0091] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0092] Those skilled in the art will appreciate that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0093] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0094] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A light source for semiconductor device measurement, characterized in that: include: A light bulb filled with xenon gas and comprising a cathode and an anode, wherein the xenon gas at the cathode forms plasma when current passes between the cathode and the anode to radiate light outwardly through a light-emitting point; A first reflector, disposed on a first side of the light bulb, for reflecting a first light emitted from the light-emitting point toward the first side and focusing the first light back to the light-emitting point; a focusing assembly, disposed on the second side of the bulb, and comprising a second reflector and a third reflector, wherein the second reflector is used to collimate the second light emitted by the light-emitting point to the second side and the first light reflected back to the light-emitting point by the first reflector to the third reflector, and then the third reflector focuses the second light and the first light to a receiving end of an optical fiber; and The optical fiber includes the receiving end and an output end, and is used to transmit the light obtained by the receiving end to the output end.

2. The light source according to claim 1, characterized in that The first reflector is a spherical reflector, wherein the light emitting point is located at twice the focal length of the first reflector, so that the first reflector reflects the first light and focuses it back to the light emitting point. The second reflector and the third reflector are both parabolic mirrors, wherein the light emitting point is located at one times the focal length of the second reflector, so that the second reflector can collimate the second light and the first light together to the third reflector, and the receiving end of the optical fiber is located at one times the focal length of the third reflector, so that the third reflector can focus the collimated first light and second light together to the receiving end of the optical fiber.

3. The light source according to claim 2, characterized in that The first reflector has an effective aperture of 45.72 mm or more, maintains a spatial angle of 0.586π or more with the light-emitting point, and has a numerical aperture of 0.45 or more, and / or The second reflector has an effective aperture of 45.72 mm or more, maintains a spatial angle of 0.586π or more with the light-emitting point, and has an object-side numerical aperture of 0.45 or more, and / or The third reflecting mirror has an effective aperture of 45.72 mm or more and an image-side numerical aperture of 0.225 or less.

4. The light source according to claim 2, characterized in that The receiving end of the optical fiber and the light emitting point are located on the same side of the focusing component, and the focusing directions of the second reflector and the third reflector are the same.

5. The light source according to claim 2, characterized in that The bulb and the first reflector constitute a first module of the light source, wherein the first reflector supports multi-degree-of-freedom adjustment in the first module to adjust the bulb to twice its focal length, The focusing assembly and the optical fiber constitute a second module of the light source, wherein the receiving end of the optical fiber supports multi-degree-of-freedom adjustment in the second module to adjust itself to one focal length of the third reflector.

6. The light source according to claim 1, characterized in that The window material of the bulb for emitting the first light and / or the second light is fused quartz glass, and / or The reflective surfaces of the first reflector, the second reflector and / or the third reflector are coated with an ultraviolet enhancement film, and / or The optical fiber is a UV optical fiber.

7. The light source according to claim 1, characterized in that The light source also includes a magnetic member, wherein: The magnetic member is located outside the bulb and on the side of the cathode facing the anode, and is used to migrate the light-emitting point from the cathode to between the cathode and the anode. The first reflector is placed at a preset tilt angle to reflect and focus the first light back to a light-emitting point between the cathode and the anode.

8. The light source according to claim 1, characterized in that Also includes: The refrigeration module is used to reduce the temperature inside the light bulb to extend the working life of the light bulb.

9. A semiconductor device measurement system, characterized in that: include: The first light source for semiconductor device measurement according to any one of claims 1 to 8; as well as The detection module is connected to the optical fiber output end of the first light source to obtain the detection light provided by the first light source, and uses the detection light to measure the semiconductor device.

10. The measuring system according to claim 9, characterized in that: The detection module includes: a wavelength selection unit, used for filtering the detection light corresponding to the measurement function from the detection light provided by the first light source; An optical unit, comprising a first beam splitter and a second beam splitter, wherein the first beam splitter is used to first transmit the detection light to a high-power objective lens and a low-power objective lens, so as to uniformly illuminate the sample to be tested on the object side thereof through the high-power objective lens or the low-power objective lens, and then transmit the first reflected light generated by the sample to be tested to the second beam splitter on the image side, so as to transmit the first reflected light to the spectrometer at the rear end through the pinhole mirror; and The spectrometer is used to collect spectrum information of the first reflected light provided by the second beam splitter to indicate the average film thickness in a first area larger than a preset size on the surface of the sample to be tested.

11. The measuring system according to claim 10, wherein: The detection module also includes: a second light source, coupled to the front end of the first beam splitter via a third beam splitter, for providing illumination light for imaging the sample to be tested, wherein the illumination light first reaches the high-power objective lens and the low-power objective lens via the first beam splitter, so as to uniformly illuminate the sample to be tested on the object side via the high-power objective lens or the low-power objective lens, and then transmits the second reflected light generated by the sample to be tested to the second beam splitter on the image side, so as to transmit the second reflected light to the rear camera via the pinhole mirror; and The camera is used to generate a corresponding sample image according to the second reflected light transmitted to its detection surface to indicate the film thickness and / or microstructure in a second area of ​​the surface of the sample to be tested that is less than or equal to the preset size.

12. The measuring system according to claim 10, wherein: The detection module also includes: The image sensor is coupled to the rear end of the first beam splitter via a fourth beam splitter, and is used to collect images output by the high-power objective lens and / or the low-power objective lens to determine the focal plane position of the high-power objective lens and / or the low-power objective lens.

Images