A light device for etching the surface of a silicon wafer, a method of use and an etching system

Abstract

This invention relates to the field of semiconductor fabrication, specifically to an illumination device, method of use, and etching system for etching silicon wafer surfaces; a support stage for holding multiple silicon wafers; multiple light sources positioned directly above the support stage for illuminating the surface of the silicon wafers; a liquid crystal light shield disposed between the silicon wafers and the light sources, the transmittance of which can be adjusted by an electrical signal; and a control unit for controlling the transmittance of the liquid crystal light shield, so that the light emitted from the light sources forms multiple illuminated areas on the silicon wafer surface after passing through the liquid crystal light shield. The illumination device of this invention can control the TMAH etching rate of different areas on the silicon wafer surface, directly improving the TTV performance of the product, ensuring the flatness of the wafer surface after etching, effectively improving the stability of subsequent processes and product quality, while also significantly improving the product yield and further reducing material costs in the production process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor fabrication, and more specifically to a photolithography device, a method of using it, and an etching system for etching the surface of silicon wafers. Background Technology

[0002] In the current semiconductor manufacturing field, improving the sensitivity of imaging sensors, especially using CMOS (Complementary Metal Oxide Semiconductor) imaging technology, is a major research direction. To improve the sensitivity of imaging sensors, back-side illuminated (BSI) technology has been introduced. This technology involves flip-flop bonding, back-side thinning, deep trench isolation, a high-k dielectric layer, a metal grid, and open pad (pad) technology. By changing the structural layout of the sensor, light can be directly incident from the back of the sensor, thereby effectively improving the light reception efficiency and the sensor's sensitivity.

[0003] In the aforementioned process steps, back-side thinning is a crucial step. The purpose of back-side thinning is to remove a portion of the material on the back of the wafer, allowing light to penetrate more easily and reach the photodiode inside the sensor, thereby further improving the sensor's sensitivity. In this step, the existing method is to thin the wafer surface using chemical mechanical polishing (CMP). However, this process results in thickness variations in different areas of the wafer.

[0004] Total Thickness Variation (TTV) refers to the difference in thickness between different points on a wafer. Many factors contribute to this, such as non-uniform initial wafer thickness or uneven wear of the polishing pad during CMP (Chemical Motion Processing). To correct TTV caused by CMP, TMAH (Tetramethylammonium Hydroxide) is typically used as an etchant to etch the epitaxial layer of the wafer. This chemical reaction removes material from the wafer surface to achieve the desired thickness. However, existing TMAH etching methods have limited effectiveness in correcting TTV because TMAH etching is isotropic, meaning the etching rate is the same in all directions. It cannot selectively remove only areas with higher thickness. Therefore, wet etching uniformly thins the surface, which can maintain or even exacerbate the TTV problem. Excessive TTV can lead to various problems during sensor manufacturing, such as uneven light spots and image distortion, severely affecting the sensor's imaging quality.

[0005] In addition, using a single-wafer etching machine results in lower production capacity, which cannot meet the needs of large-scale production and further limits production efficiency. Summary of the Invention

[0006] To address the problems mentioned in the prior art, this invention proposes a light illumination device, a method of use, and an etching system for etching the surface of silicon wafers. The light illumination device can effectively control the total thickness change of the wafer during the back-side thinning process. In addition, an etching system is proposed that can upgrade the etching of single-wafer silicon wafers to batch-process silicon wafers, greatly improving production efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a photoluminescence device for etching the surface of a silicon wafer, comprising:

[0009] A support platform, used to hold multiple silicon wafers;

[0010] Multiple light sources are positioned directly above the support platform to illuminate the surface of the silicon wafer.

[0011] A liquid crystal light shield is disposed between a silicon wafer and a light source, and the light transmittance of the liquid crystal light shield can be adjusted by an electrical signal.

[0012] The control unit is used to control the transmittance of the liquid crystal light shield so that the light emitted by the light source forms multiple illuminated areas on the silicon wafer surface after passing through the liquid crystal light shield.

[0013] The number of light sources and liquid crystal light shields are the same and they are set in a one-to-one correspondence.

[0014] Each liquid crystal light shield has a light-transmitting area, and each light-transmitting area is configured to allow light emitted from a light source corresponding to that light-transmitting area to be guided to the silicon wafer surface, forming one of a plurality of illumination areas on the silicon wafer surface.

[0015] As a further improvement of the present invention, the control unit includes a transmission module, a data processing module, and a light intensity processing module connected in sequence.

[0016] The transmission module is used to acquire thickness measurement data of each illuminated area on the silicon wafer surface;

[0017] The data processing module is used to determine the etching rate corresponding to each irradiated area based on the thickness measurement data of each irradiated area, and to determine the required light intensity for each irradiated area based on the etching rate.

[0018] The light intensity processing module is used to calculate the light transmittance of the corresponding light-transmitting area on the liquid crystal light shielding plate according to the light intensity and light source intensity required for each illumination area, and to generate control signals.

[0019] As a further improvement of the present invention, the data processing module determines the required light intensity for each illuminated area according to the following formula:

[0020]

[0021] In the formula: Indicates the first Etching rate of each illuminated area; This indicates the etching rate under no light illumination. Indicates the maximum rate of light enhancement; Indicates the intensity of half-saturated light; Indicates the first The required light intensity for each illuminated area.

[0022] As a further improvement of the present invention, the light source is a UV light source.

[0023] As a further improvement of the present invention, it also includes a conveying device, wherein the support platform is disposed on the conveying device.

[0024] As a further improvement of the present invention, the support stage includes a substrate and at least one loading stage, wherein the loading stages are arranged sequentially at intervals along the length direction of the substrate, and the loading stages are used to hold silicon wafers.

[0025] As a further improvement of the present invention, the conveying device includes a conveyor belt, and baffles are fixedly provided on both sides of the conveyor belt.

[0026] Secondly, the present invention provides a method of using a photoluminescence device for etching the surface of a silicon wafer, comprising the following steps:

[0027] The required illumination intensity for each illumination area is determined based on the etching rate;

[0028] The control signal for determining the light transmittance of the corresponding light-transmitting area on the liquid crystal light shield is based on the light intensity required for each illuminated area.

[0029] The control signal drives the liquid crystal light shield to change the light transmittance, and the light source illuminates the surface of the silicon wafer.

[0030] Thirdly, the present invention proposes a silicon wafer etching system, which, based on the above-mentioned illumination device for etching the surface of a silicon wafer, further includes a transfer unit and an etching unit, wherein the illumination device is connected to the transfer unit and the transfer unit is connected to the etching unit.

[0031] The transfer unit is used to integrate the silicon wafers processed by the irradiation device into batch silicon wafers;

[0032] The etching unit is used to perform uniform wet etching on batches of silicon wafers from the transit unit.

[0033] Compared with the prior art, the present invention has achieved the following unexpected technical effects:

[0034] The illumination device of this invention illuminates a silicon wafer before etching, determines the required etching rate for each illuminated area based on thickness measurement data of each illuminated area on the silicon wafer surface, calculates the required light intensity for each illuminated area based on the etching rate, and applies different light intensities to each illuminated area on the silicon wafer surface by controlling the light transmittance of the corresponding light-transmitting area of ​​the liquid crystal light-shielding plate. Irradiation activates and modifies the silicon wafer surface, increasing its hydrophilicity and thus altering the etching rate. This makes the etching rate of each illuminated area more uniform. Through uniform etching in subsequent etching processes, TTV can be further reduced, product performance improved, and the flatness of the wafer surface after etching ensured. This effectively improves the stability of subsequent processes and product quality, significantly increases product yield, further reduces material costs in the production process, and brings economic benefits to enterprises.

[0035] The etching system of the present invention can upgrade single silicon wafers into batch silicon wafers through a transfer unit. By changing the etching rate of each irradiated area of ​​the silicon wafer through a front-end illumination device, the etching rate of each irradiated area tends to be consistent. Therefore, batches of silicon wafers can be uniformly wet etched. The system not only improves production efficiency and reduces production costs, but also effectively avoids the influence of environmental factors such as TMAH temperature and oxygen concentration on the etching rate. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the photolithography device for etching silicon wafer surfaces according to the present invention;

[0037] Figure 2 This is a schematic diagram of the support platform structure of the photolithography device for etching silicon wafer surfaces according to the present invention;

[0038] Figure 3 This is a schematic diagram of the light source and liquid crystal light shield of the illumination device for etching silicon wafer surface according to the present invention;

[0039] Figure 4 This is a schematic diagram of the connection of the light processing unit of the light illumination device for etching silicon wafer surface according to the present invention;

[0040] Figure 5 This is a schematic diagram of the photo-processing unit for etching silicon wafer surfaces according to the present invention;

[0041] Figure 6 This is a schematic diagram of the structure of a silicon wafer etching system according to the present invention.

[0042] Reference numerals in the attached drawings: 1. Light source; 2. Liquid crystal light shield; 3. Support platform; 4. Conveying device; 5. Support; 6. Base plate; 7. Loading platform. Detailed Implementation

[0043] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0049] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0051] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0052] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0053] Example 1

[0054] In the existing semiconductor manufacturing process, a key step is to use light to irradiate the surface of the silicon wafer for subsequent etching. However, due to the thickness deviation in different areas of the silicon wafer surface caused by the previous back-side thinning process, and the fact that the silicon wafer surface is usually irradiated uniformly during the irradiation process, the required etching rate for each area of ​​the silicon wafer surface is different in the subsequent etching process because the thickness of different areas of the silicon wafer surface is already different, but the light intensity is uniformly irradiated.

[0055] In view of this, such as Figure 1 As shown, the present invention proposes a photoluminescence device for etching the surface of silicon wafers, comprising: a support platform 3 for holding multiple silicon wafers; a light source 1, wherein multiple light sources 1 are arranged directly above the support platform 3 for illuminating the surface of the silicon wafers; a liquid crystal light shield 2, disposed between the silicon wafers and the light sources 1, wherein the transmittance of the liquid crystal light shield 2 can be adjusted by an electrical signal; and a control unit for controlling the transmittance of the liquid crystal light shield 2, so that the light emitted by the light sources 1 forms multiple illuminating areas on the surface of the silicon wafers after passing through the liquid crystal light shield 2.

[0056] In this embodiment, multiple silicon wafers can be placed on the support stage 3. When the silicon wafers are transported to the bottom of the light source 1, the light emitted by the light source 1 will pass through multiple liquid crystal light shields 2 and irradiate the surface of the silicon wafer to form an irradiated area. The position of the light-transmitting area of ​​each liquid crystal light shield 2 is different, and the light transmittance of each light-transmitting area can be controlled independently. Through the cooperation of multiple light sources 1 and liquid crystal light shields 2, different irradiated areas on the surface of the silicon wafer can receive light of different intensities. Since the thickness of each irradiated area on the surface of the silicon wafer is the same or different, by calculating the etching rate required for each irradiated area, the required light intensity of each irradiated area can be determined according to the etching rate. This can change the etching rate of different irradiated areas on the surface of the silicon wafer, making the etching rate of each area tend to be uniform, so that the silicon wafer can be etched uniformly in subsequent etching processes, which can further reduce TTV, effectively improve the overall performance of the product, and ensure the flatness of the wafer surface after etching.

[0057] like Figure 1 As shown, in this embodiment, the number of light sources 1 and liquid crystal light shields 2 are adapted to each other. Each liquid crystal light shield 2 includes a light-transmitting area, and the position of the light-transmitting area completely coincides with the position of one of the multiple light-illuminating areas. Figure 1 Each light source 1 is provided with a liquid crystal light shield 2 below it, which not only ensures the control of the light source 1, but also makes the device more flexible. The number of light sources 1 can be adjusted according to actual production needs. The number of light sources 1 can be increased or decreased according to the area size and number of areas of each region of the silicon wafer. Therefore, the embodiment does not limit the number of light sources 1.

[0058] The device in this embodiment has a total of 5 light sources 1, and each light source 1 is arranged sequentially at intervals according to quantity. Figure 1 In the diagram, the five light sources 1 are labeled A, B, C, D, and E respectively for identification purposes. In addition, the shape and size of the light sources 1 are adapted to the liquid crystal light shield 2, which can ensure that the liquid crystal light shield 2 can completely block the light sources 1 and prevent the light sources 1 from leaking from the edge of the liquid crystal light shield 2, thereby avoiding unnecessary light exposure to the silicon wafer.

[0059] Existing silicon wafers are usually circular, so the shape of the liquid crystal light shield 2 in this embodiment is the same as that of the silicon wafer, which is also circular. In this embodiment, the liquid crystal light shield 2 uses transparent liquid crystal material as a current control switch. The transparency of the light shield is changed by controlling the on and off of the current. When the current passes through the liquid crystal layer, the arrangement of the liquid crystal molecules will change, thereby changing the light transmittance of the material. By controlling the magnitude of the current and voltage, the light transmittance of the liquid crystal light shield 2 can be precisely adjusted.

[0060] Figure 1 and Figure 3 As shown in the illustration, the embodiment divides the light-transmitting areas of the five liquid crystal light-shielding plates 2. For example, the light-transmitting area of ​​the liquid crystal light-shielding plate 2 labeled A is a circle centered on the center of the silicon wafer; the light-transmitting area of ​​the liquid crystal light-shielding plate 2 labeled B is the innermost inner circle of the concentric rings centered on the center of the silicon wafer; the light-transmitting area of ​​the liquid crystal light-shielding plate 2 labeled C is the middle ring of the concentric rings centered on the center of the silicon wafer, closer to the inner ring; the light-transmitting area of ​​the liquid crystal light-shielding plate 2 labeled D is the middle ring of the concentric rings centered on the center of the silicon wafer, farther away from the concentric rings; and the light-transmitting area of ​​the liquid crystal light-shielding plate 2 labeled E is the outermost outer circle of the concentric rings centered on the center of the silicon wafer. By combining and positioning the light-transmitting areas of the five liquid crystal light-shielding plates 2, it is ensured that each light-illuminated area on the silicon wafer can obtain the required light intensity.

[0061] In the process of dividing the concentric rings described above, the width and area of ​​each ring are designed according to the thickness requirements of different regions in the back-side thinning process of the silicon wafer. Specifically, the width of each ring can be set to be the same or different according to actual needs to adapt to the thickness gradient or thickness requirements of specific regions that may exist in the back-side thinning process of the silicon wafer. Similarly, the area of ​​the rings can also be adjusted according to the importance, processing difficulty or expected performance of different regions on the silicon wafer to achieve uniform distribution in area or processing of specific regions. Therefore, in this embodiment, the silicon wafer is divided into illumination region A, illumination region B, illumination region C, illumination region D and illumination region E.

[0062] In this embodiment, the light transmittance of each liquid crystal light shield 2's light-transmitting area may be the same or different. In this device, the light transmittance of the liquid crystal light shield 2 refers to the ratio of the intensity of the remaining light after light passes through the light-transmitting area of ​​the liquid crystal light shield 2 to the intensity of the incident light, reflecting the light shield's ability to transmit light. In this invention, the light intensity is related to the light transmittance of the liquid crystal light shield 2 and the intensity of the light source 1. Therefore, when the intensity of the light source 1 is set to a constant value, adjusting the change in light intensity will mainly rely on adjusting the light transmittance of the liquid crystal light shield 2.

[0063] Based on the above principle, the light intensity can be precisely controlled by changing the light transmittance of the liquid crystal light shield 2. When it is necessary to enhance the light, the light transmittance of the liquid crystal light shield 2 can be increased to allow more light to pass through; conversely, when the light is weakened, the light transmittance of the liquid crystal light shield 2 can be reduced to reduce the transmission of light. Through this light intensity adjustment method, different TMAH etching efficiencies in different areas of the silicon wafer surface can be ensured.

[0064] like Figure 4 As shown in the embodiment, an illumination processing unit is proposed, which is connected to a liquid crystal light-shielding plate 2. The illumination processing unit includes a transmission module, a data processing module, and a light intensity processing module connected in sequence; the transmission module is used to acquire thickness measurement data of each illumination area on the silicon wafer surface; the data processing module is used to determine the etching rate corresponding to each illumination area based on the thickness measurement data of each illumination area, and determine the required illumination intensity of each illumination area based on the etching rate; the light intensity processing module is used to calculate the transmittance of the corresponding light-transmitting area on the liquid crystal light-shielding plate 2 based on the required illumination intensity of each illumination area and the light source intensity, and generate a control signal.

[0065] like Figure 5 As shown, the working process of the light processing unit is as follows: First, based on the THK (Thickness) measurement performed on the silicon wafer after CMP thinning, the thickness of the silicon wafer surface is measured to generate data on the silicon wafer thickness. The embodiment uses... Figure 1 As shown in the example, the transmission module divides the silicon wafer surface area into illumination area A, illumination area B, illumination area C, illumination area D, and illumination area E. The thickness of each illumination area is recorded as T1, T2, T3, T4, and T5, respectively, and the data is uploaded to the data processing module.

[0066] The data processing module sets the target value of the silicon wafer thickness after TMAH etching as T0, and calculates the TMAH etching rates ER corresponding to the A, B, C, D, and E illumination regions of the silicon wafer, respectively denoted as ER1, ER2, ER3, ER4, and ER5. The calculation formulas are as follows:

[0067] =(Thickness of each region Ti - Target thickness T0 after TMAH etching) / TMAH time

[0068] The data processing module calculates the required illumination intensities W1, W2, W3, W4, and W5 for illumination regions A, B, C, D, and E of the silicon wafer based on the obtained relationship between etching rate and light intensity. The calculation formulas are shown below:

[0069]

[0070] In the formula: Indicates the first Etching rate of each illuminated area; This indicates the etching rate under no light illumination. Indicates the maximum rate of light enhancement; Indicates the intensity of half-saturated light; Indicates the first The required light intensity for each illuminated area.

[0071] Half-saturated light intensity in the embodiment The intensity of light is determined by the etching rate, as shown in the following formula. When the etching rate is satisfied, the light intensity is the half-saturated light intensity.

[0072]

[0073] The light intensity processing module calculates the light transmittance T1, T2, T3, T4, and T5 of the liquid crystal light shield corresponding to the illumination areas A, B, C, D, and E of the silicon wafer, based on the functional relationship between the obtained light intensity and the transmittance of the liquid crystal light shield. The calculation formula is shown below:

[0074]

[0075] In the formula: Light transmittance; Indicates light intensity; Indicates the intensity of the light source.

[0076] A voltage is applied to the five liquid crystal light-blocking plates 2 to change the transmittance of different light-transmitting areas, thereby changing the light intensity W reaching the silicon wafer surface. In this embodiment, the relationship between transmittance and voltage V is shown in the following formula:

[0077] Ti=aV b (a and b are constants that can be obtained experimentally)

[0078] In this embodiment, the light source 1 is preferably a UV light source for illumination, which can activate and modify the silicon wafer surface, improve the hydrophilicity of the silicon wafer surface, and thus change the TMAH etching rate. The UV light source has the characteristics of stable output, high resolution and high energy density, which can ensure the accuracy and efficiency of the etching process. However, it is not limited to this. Other types of light sources, such as EUV light sources and laser light sources, can be selected according to specific production needs and process requirements. The selection can be flexible according to actual needs. Therefore, this embodiment does not limit the type of light source 1.

[0079] like Figure 2 As shown, the support platform 3 includes a substrate and at least one carrying platform 7. The carrying platforms 7 are arranged sequentially and spaced apart along the length of the substrate, and are used to hold silicon wafers. In this embodiment, the support platform 3 is preferably rectangular, which facilitates handling by workers. The support platform 3 includes a base plate 6, which provides a stable support foundation. Supports 5 are connected to both ends of the base plate 6. The purpose of the supports 5 is to enhance the stability of the base plate 6 and ensure that it will not tilt when carrying silicon wafers, thus further improving the structural stability. Multiple carrying platforms 7 are provided on the base plate 6. The carrying platforms 7 are used to carry silicon wafers. In order to ensure that the silicon wafers can be placed stably, various connection methods are adopted between the carrying platforms 7 and the support platform 3. Traditional screw or bolt fixing methods can be selected to ensure a firm and reliable connection. Alternatively, an integrated molding method can be selected to reduce assembly steps and improve the compactness of the overall structure. Of course, other connection methods can also be selected, such as magnetic connection, snap-fit ​​connection, slot connection, etc. Regardless of the connection method chosen, the connection stability must be ensured to prevent loosening during long-term use.

[0080] In this embodiment, the stage 7 is designed with the size and characteristics of the silicon wafer in mind. The stage 7 is set to be larger than the size of the silicon wafer so that even if the silicon wafer shifts during placement, it can be steadily supported by the stage 7, effectively avoiding damage to the silicon wafer due to instability. In addition, the surface of the stage 7 has undergone special treatment, such as anti-slip treatment or anti-static treatment, to further ensure the safety and reliability of the silicon wafer.

[0081] In this embodiment, the conveying device 4 is preferably a conveyor belt, with baffles fixedly installed on both sides of the conveyor belt. The choice of a conveyor belt for conveying is based on its continuous and stable conveying characteristics. Using a conveyor belt simplifies the production process, and the baffles fixedly installed on both sides further ensure stability and safety during the transmission process on the carrier platform 3, effectively preventing incomplete illumination of the silicon wafers due to shaking or displacement.

[0082] In this embodiment, a conveyor belt is used for silicon wafer transport, enabling seamless integration of automated production lines and significantly improving efficiency. Since the thickness of each silicon wafer surface area varies, the corresponding light intensity also differs. As the silicon wafers on the support platform 3 pass sequentially through the light source 1, the light source 1 can dynamically adjust the transmittance of the liquid crystal light shield 2 based on the thickness data of each silicon wafer surface to output appropriate light intensity. This ensures that each silicon wafer surface area receives suitable light intensity, allowing different areas of each silicon wafer surface to react at different TMAH etching rates, facilitating subsequent etching processes, effectively improving the TTV performance of the product, and ensuring the flatness of the wafer surface after etching. Furthermore, the speed and direction of the conveyor belt can be adjusted according to production needs to adapt to different production rhythms and process requirements.

[0083] In addition to conveyor belts, other conveying devices can also be used in the embodiments, such as roller conveyors, which mainly use the rolling of rollers to transport silicon wafers; or chain conveyors, which mainly use the traction force of chains to transport silicon wafers, suitable for scenarios that require precise control of the transmission position and speed.

[0084] Example 2

[0085] This embodiment is basically the same as Embodiment 1, except that this embodiment proposes a silicon wafer etching system, including a light illumination device for etching the silicon wafer surface, a transfer unit and an etching unit, wherein the light illumination device for etching the silicon wafer surface is connected to the transfer unit and the transfer unit is connected to the etching unit.

[0086] like Figure 6 As shown, the system in this embodiment also includes a conveying unit, preferably a robotic arm, which can accurately place the silicon wafers that have undergone the back-side thinning process onto the carrier platform. In conjunction with the control system that controls the movement of the robotic arm, the position of the silicon wafers can be controlled to ensure that the silicon wafers are not damaged during placement. At the same time, it ensures the precision and accuracy of placement on the carrier platform, which not only improves the automation level of the production line, but also reduces the errors and risks caused by manual operation.

[0087] Of course, this is not all. Depending on specific production needs and process requirements, such as the size, weight, and shape of the silicon wafers, as well as the overall layout and process requirements of the production line, other conveying devices can be selected, such as suction cup devices. Suction cup devices use the principle of negative pressure adsorption to firmly grasp the silicon wafers and place them stably on the carrier platform. Compared with robotic arms, suction cup devices may have lower costs and simpler structures, so they can be selected according to actual needs.

[0088] The transit unit in this embodiment can integrate individual silicon wafers into batch silicon wafers to facilitate subsequent etching processes. Taking 25pcs / Lot as an example, Lot is the batch number, and pcs (pieces) indicates that 25 silicon wafers are integrated together to form a batch for unified processing. Each crystal box contains 25 silicon wafers, but it is not limited to this number. Instead, it can be flexibly adjusted according to production needs and process requirements. To ensure the accuracy and traceability of each Lot, this embodiment assigns a unique ID to each Lot. The ID can not only quickly identify and track the status and location of each Lot, but also trace and troubleshoot problems in a timely manner, ensuring the stability and reliability of the production process.

[0089] The transfer unit can use traditional manual sorting or automated sorting devices to improve sorting efficiency and accuracy. Automated sorting devices, through sensors and control systems, can quickly identify and sort silicon wafers, greatly shortening sorting time, reducing labor costs, and improving sorting accuracy and stability.

[0090] In this embodiment, the etching unit preferably employs wet etching, specifically using automated wet etching equipment manufactured by Tokyo Electron Limited (TEL). This equipment can etch different areas of the silicon wafer in the shortest process time based on the intensity of the preceding light, and can process multiple silicon wafers at once, replacing the existing single-wafer machine. This not only greatly improves production efficiency and reduces production costs, but also effectively avoids the influence of environmental factors such as TMAH temperature and oxygen concentration on the etching rate, thereby improving the overall quality and consistency of the product.

[0091] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0092] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A photoluminescence device for etching the surface of a silicon wafer, characterized in that, include: The support platform (3) is used to hold multiple silicon wafers; A light source (1) is located directly above the support platform (3) to illuminate the surface of the silicon wafer. A liquid crystal light shield (2) is disposed between the silicon wafer and the light source (1), and the transmittance of the liquid crystal light shield (2) can be adjusted by an electrical signal. The control unit is used to control the transmittance of the liquid crystal light shield (2) so that the light emitted by the light source (1) forms multiple illumination areas on the silicon wafer surface after passing through the liquid crystal light shield (2); the control unit includes a transmission module, a data processing module and a light intensity processing module connected in sequence. The transmission module is used to acquire thickness measurement data of each illuminated area on the silicon wafer surface; The data processing module is used to determine the etching rate corresponding to each irradiated area based on the thickness measurement data of each irradiated area, and to determine the required light intensity for each irradiated area based on the etching rate. The light intensity processing module is used to calculate the light transmittance of the corresponding light-transmitting area on the liquid crystal light shield (2) according to the light intensity and light source intensity required for each light-illuminated area, and generate control signals; The number of light sources (1) and liquid crystal light shields (2) are the same and they are set in a one-to-one correspondence; Each liquid crystal light shield (2) has a light-transmitting area, and each light-transmitting area is configured to allow light emitted by the light source (1) corresponding to the light-transmitting area to be directed to the silicon wafer surface, forming one of a plurality of illumination areas on the silicon wafer surface.

2. The illumination device for etching the surface of a silicon wafer according to claim 1, characterized in that, The data processing module determines the required light intensity for each illuminated area according to the following formula: In the formula: Indicates the first Etching rate of each illuminated area; This indicates the etching rate under no light illumination. Indicates the maximum rate of light enhancement; Indicates the intensity of half-saturated light; Indicates the first The required light intensity for each illuminated area.

3. The illumination device for etching the surface of a silicon wafer according to claim 1, characterized in that, The light source (1) is a UV light source.

4. The illumination device for etching the surface of a silicon wafer according to claim 1, characterized in that, It also includes a conveying device (4), and the carrier platform (3) is disposed on the conveying device (4).

5. The illumination device for etching the surface of a silicon wafer according to claim 1, characterized in that, The support platform (3) includes a substrate and at least one loading platform. The loading platforms are arranged sequentially at intervals along the length of the substrate and are used to hold silicon wafers.

6. The illumination device for etching the surface of a silicon wafer according to claim 4, characterized in that, The conveying device (4) includes a conveyor belt, and baffles are fixedly provided on both sides of the conveyor belt.

7. A method of using a photoillumination apparatus for etching a silicon wafer surface, based on the photoillumination apparatus for etching a silicon wafer surface as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Acquire thickness measurement data for each illuminated region on the silicon wafer, and determine the etching rate for each illuminated region based on the thickness measurement data; The required illumination intensity for each illumination area is determined based on the etching rate; The control signal for determining the transmittance of the corresponding light-transmitting area on the liquid crystal light shield (2) is determined according to the light intensity required for each light-emitting area; The transmittance of the liquid crystal light shield (2) is changed by the control signal, and the silicon wafer surface is illuminated by the light source (1).

8. A silicon wafer etching system, based on the photoluminescence device for etching the surface of a silicon wafer as described in any one of claims 1 to 6, characterized in that, It also includes a transfer unit and an etching unit, wherein the illumination device is connected to the transfer unit and the transfer unit is connected to the etching unit; The transfer unit is used to integrate the silicon wafers processed by the irradiation device into batch silicon wafers; The etching unit is used to perform uniform wet etching on batches of silicon wafers from the transit unit.

Images