Process for thinning base material in light emitting diode
By pre-thinning treatment and wax layer formation on the edge of the substrate, the problem of high lobe rate caused by uneven substrate thickness is solved, the uniformity and stability of the substrate thinning process is achieved, and the yield of the substrate is improved.
Patent Information
- Application Number
- CN202510615321.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-13
- Publication Date
- 2025-08-12
AI Technical Summary
In the prior art, there is a problem of high lobe rate caused by uneven substrate thickness in the light emitting diode substrate thinning process.
By pre-thinning the second surface edge of the substrate and forming a wax layer on the first surface, the wax layer is sprayed by high-temperature atomization spraying method, combined with the precise bonding and protective layer treatment of the substrate, the thickness uniformity and stress uniformity of the substrate are ensured, and lobes caused by excessive local stress are reduced.
The uniformity and stability of the thinning process of the substrate is achieved, the lobe rate is reduced, and the yield of the substrate is improved.
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Figure CN120475823A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of LED (Light Emitting Diode), and in particular to a thinning process for a substrate in a light emitting diode. Background Art
[0002] In various LED manufacturing processes, the substrate (substrate) thickness thinning process is an indispensable part, which is mainly to increase the heat dissipation and photoelectric properties of the LED during subsequent use.
[0003] In the prior art, due to factors in the epitaxial process or the substrate manufacturing process, the thickness of the edge of the substrate is thicker than the center thickness. The thickness of the substrate after thinning is uneven and the cracking rate is high. Summary of the Invention
[0004] The present application provides a thinning process for a substrate in a light-emitting diode, so as to at least solve the problem of a high cracking rate caused by uneven substrate thinning thickness in the thinning process for a light-emitting diode in the related art.
[0005] The present application provides a thinning process for a substrate in a light-emitting diode, comprising: providing a substrate having a first surface and a second surface opposite to each other; performing a pre-thinning treatment on an edge of the second surface, wherein the pre-thinning treatment range extends inward from the edge of the second surface by 1 mm to 3 mm; forming a wax layer on the first surface; pressing a substrate against the wax layer so that the substrate is adhered to the substrate; performing a thinning treatment on the second surface of the substrate adhered to the substrate; separating the thinned substrate from the substrate, and dewaxing and cleaning the substrate.
[0006] Through the present application, the edge of the second surface of the substrate is first pre-thinned to ensure that the difference between the edge thickness and the center thickness of the substrate after the pre-thinning treatment is small, thereby ensuring that the thickness of the wax layer applied to the first surface of the substrate after the pre-thinning treatment is relatively uniform, that is, the unevenness of the wax layer after patching caused by the difference in thickness of the substrate edge is reduced, and the thickness of the substrate after subsequent thinning treatment is relatively uniform, thereby reducing the local stress unevenness of the substrate caused by thermal expansion, cooling, machining or microstructure differences due to uneven thickness, thereby maintaining the relative uniformity of the stress distribution inside the substrate, reducing the cracks caused by excessive local stress, ensuring a low crack rate of the substrate, and ensuring a high yield of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0008] Figure 1 A schematic diagram of a process for thinning a substrate in a light-emitting diode provided in an embodiment of the present application;
[0009] Figure 2 A schematic diagram of a structure for pre-thinning the edge of a substrate using a thinning medium provided in an embodiment of the present application;
[0010] Figure 3 A schematic diagram of a structure for pressing a substrate to a base material for patching provided in an embodiment of the present application;
[0011] Figure 4 A schematic top view of heating and melting a wax layer on the edge of a substrate provided in an embodiment of the present application. DETAILED DESCRIPTION
[0012] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0013] It should be noted that, in the description of this application, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. The terms "first," "second," etc., in this application are used to distinguish similar objects, and are not used to describe a particular order or sequence.
[0014] Different types of substrate thinning processes have different requirements for the final thinning thickness, and different types of substrate materials, such as silicon, gallium arsenide, gallium nitride, and silicon carbide, also have corresponding appropriate thinning thicknesses. Although the substrate thinning process is very mature and has achieved large-scale production, the process yield during the thinning process also varies due to differences in process technology and the precision of the equipment itself. The two most important factors affecting the yield are splinters and surface contamination. Splinters are caused by uneven stress and heating of the LED due to external forces during the thinning process, while surface contamination is often related to residual glue on the surface, the dewaxing and cleaning process, and the material of the substrate itself. Currently, there is no effective method to achieve zero splinters and zero contamination, and the general yield can be controlled above 90%. However, for some high-cost LEDs, even a defective rate of 0.1% can significantly affect the company's profitability.
[0015] The conventional substrate thinning process generally involves coating wax on a substrate, then attaching the substrate to the wax liquid, and then achieving the attachment through a tablet pressing device and cooling process. However, this method causes the edge thickness to be higher than the center thickness due to factors such as the epitaxial process or the substrate manufacturing process, resulting in uneven thickness of the wax layer after the substrate is attached, ultimately leading to uneven thickness of the substrate thinning.
[0016] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0017] The embodiments of the present application provide a thinning process for a substrate in a light-emitting diode, and the method is described in detail in conjunction with the execution flow of the thinning process for a substrate in a light-emitting diode.
[0018] Figure 1 FIG. 1 is a flow chart of a thinning process for a substrate in a light-emitting diode according to an embodiment of the present application. Figure 1 As shown, the thinning process of the substrate in the light-emitting diode includes the following steps:
[0019] Step S101, providing a substrate, wherein the substrate has a first surface and a second surface opposite to each other;
[0020] Step S102, performing a pre-thinning process on the edge of the second surface, wherein the pre-thinning process has a processing range extending inward from the edge of the second surface by 1 mm to 3 mm;
[0021] Step S103, forming a wax layer on the first surface;
[0022] Step S104, pressing the substrate toward the wax layer so that the base material adheres to the substrate;
[0023] Step S105, performing a thinning process on the second surface of the substrate attached to the base plate;
[0024] In step S106 , the thinned substrate is separated from the base plate, and the substrate is dewaxed and cleaned.
[0025] Through the above embodiment, the edge of the second surface of the substrate is first pre-thinned to ensure that the difference between the edge thickness and the center thickness of the substrate after the pre-thinning treatment is small, thereby ensuring that the thickness of the wax layer applied to the first surface of the substrate after the pre-thinning treatment is relatively uniform, that is, the unevenness of the wax layer after patching caused by the difference in the thickness of the substrate edge is reduced, and the thickness of the substrate after subsequent thinning treatment is relatively uniform, thereby reducing the local stress unevenness of the substrate caused by thermal expansion, cooling, machining or microstructure differences due to uneven thickness, thereby maintaining the relative uniformity of the stress distribution inside the substrate, reducing the cracks caused by excessive local stress, ensuring a low crack rate of the substrate, and ensuring a high yield of the substrate.
[0026] Specifically, the edge of the second surface of the substrate is pre-thinned and then cleaned.
[0027] Specifically, when the second surface is thinned, the substrate is thinned according to a normal thinning process, and then the substrate and the base plate are cleaned.
[0028] In one optional embodiment, forming a wax layer on the first surface includes spraying melted liquid wax onto the first surface using a high-temperature atomizing spray method and allowing the wax layer to stand for 10 to 20 seconds to form the wax layer. The temperature in the high-temperature atomizing spray method is the temperature at which the wax is converted from a solid state to a liquid state. In this embodiment, the high-temperature atomizing spray method enables the liquid wax to be evenly coated on the first surface of the substrate in the form of tiny droplets. Compared with direct coating or conventional spraying methods, this method can significantly improve the uniformity of the wax layer thickness, thereby ensuring better uniformity during subsequent substrate thinning. In addition, at high temperatures, the fluidity of the liquid wax increases, enabling better contact with the substrate surface and forming a strong adhesion. After rapid cooling, this uniform and strong adhesion helps stabilize the substrate during the thinning process, reducing substrate displacement or vibration caused by poor adhesion, and further reducing the possibility of cracking.
[0029] Specifically, the temperature in the high-temperature atomization spraying mode is 100°C-120°C.
[0030] Specifically, the spraying amount of the wax (in milliliters) is 0.2-0.3 times the area of the first surface of the substrate (in square centimeters).
[0031] Specifically, a high-temperature atomized spray method is used to spray wax onto the first surface based on a preset spray angle, with the spray angle ranging from 20 to 45 degrees. The spray angle is the angle between the spray port and the first surface. By adjusting the spray angle, the surface tension formed when the wax droplets vertically impact the surface can be reduced, avoiding localized accumulation of the wax layer due to surface tension, thereby improving the uniformity of the wax layer. Furthermore, the spray angle and / or wax spray path can be dynamically adjusted based on the real-time distribution of the wax liquid.
[0032] Specifically, after pre-thinning the edge of the second surface and before forming the wax layer on the first surface, the thinning process of the substrate in the light-emitting diode further includes: using a laser to micro-roughen the first surface of the substrate. Furthermore, specific areas of the first surface (such as edge areas where adhesion needs to be enhanced) can be micro-roughened. The micro-roughening of the substrate surface significantly increases the contact area with the wax layer and enhances the adhesion between the wax layer and the substrate, thereby reducing displacement or falling off caused by insufficient adhesion during the patch process.
[0033] According to some exemplary embodiments of the present application, the thinning angle of the pre-thinning treatment is 1 degree to 3 degrees, the thinning angle represents the angle between the thinning medium and the second surface, the particle size of the thinning medium is less than 10 microns, and the thinning medium represents the medium for grinding or grinding the substrate in the pre-thinning treatment. In this embodiment, a specific angle (1 degree to 3 degrees) is used for grinding or grinding in the pre-thinning treatment, which can accurately control the thinning profile and ensure that the bevel after the substrate edge is thinned is beneficial to the subsequent process (such as improving the uniformity of the wax layer during patching) and avoids the decrease in structural strength caused by excessive thinning; the thinning medium with fine particle size (less than 10 microns) produces less surface damage during grinding or grinding, avoids local stress concentration that may be caused by coarse particles, and further reduces the risk of substrate cracking during the thinning process; the fine-grained thinning medium and the bevel pre-thinning design make it easier to clean the residual medium and debris generated by thinning, reducing the probability of these residues contaminating the substrate surface in subsequent processes, thereby further improving the yield of the finished product.
[0034] Figure 2 Schematic diagram of pre-thinning the edge of the substrate using a thinning medium. Figure 2 As shown, A represents the thinning angle.
[0035] In other embodiments, after pre-thinning the edges of the second surface and before forming the wax layer on the first surface, the thinning process for the substrate in the LED further includes: applying monolauryl phosphate to the first surface, heating the substrate coated with monolauryl phosphate to 70°C-80°C, and controlling the rotation of the heated substrate for 30-50 seconds at a speed of 500-800 rpm to form a first protective layer on the first surface. In this embodiment, the monolauryl phosphate is evenly distributed on the first surface of the substrate due to the heating and rotation, forming a protective film. This protective film can prevent grinding residues or contaminants from directly adhering to the substrate surface during the subsequent thinning and wax removal processes, thereby reducing the risk of surface contamination.
[0036] Specifically, the heated substrate is controlled to rotate at a high speed for 30-50 seconds.
[0037] Specifically, after the heated substrate is controlled to rotate for 30-50 seconds and before the wax layer is formed on the first surface, the thinning process of the substrate in the light-emitting diode further includes: placing the substrate face up on a heating table and heating and keeping it warm at a heating temperature of 100°C-110°C.
[0038] Specifically, a first protective layer is spin-coated on the first surface of the substrate to prevent grinding residues or contaminants from causing difficult-to-clean contamination to the substrate during unloading.
[0039] According to other exemplary embodiments of the present application, the substrate is pressed against the wax layer, comprising: placing the substrate on a table so that the second surface is in contact with the table; pressing the substrate vertically downwards from directly above the substrate to the substrate, maintaining the pressing for 10 seconds to 20 seconds, with a pressure of 0.3Mpa to 0.4Mpa. In this embodiment, the method of vertical pressing from directly above is adopted to minimize the edge effect, that is, the edge position of the substrate is not tightly or unevenly fitted. The edge effect may cause uneven thinning of the edge portion. This problem can be effectively avoided by accurately controlling the pressing process; by accurately controlling the downward pressure (0.3Mpa to 0.4Mpa) and time (10 seconds to 20 seconds), the close fit between the substrate and the substrate can be ensured, bubbles or gaps in the laminating process can be reduced, and the accuracy and consistency of the laminating can be improved. This precise fitting is conducive to the subsequent thinning process and ensures the stability of the substrate during the thinning process.
[0040] Specifically, the patch is: slowly press the substrate vertically downward from directly above the substrate and hold for 10-20 seconds.
[0041] Figure 3 Schematic diagram of pressing the substrate to the base material for patching. Figure 3 As shown, the substrate is placed on a platform with the front side (ie, the first surface) of the substrate facing upward, and the base plate is pressed vertically downward toward the substrate from directly above the substrate.
[0042] In some other optional solutions of the present application, after the substrate is pressed vertically downward from directly above the substrate and maintained for 10 seconds to 20 seconds, before the second surface of the substrate attached to the substrate is thinned, the thinning process of the substrate in the light-emitting diode further includes: spraying a sodium dodecyl sulfate solution on the side of the substrate and letting it stand for 30 seconds to 60 seconds to form a second protective layer on the side, the side being all surfaces of the substrate except the first surface and the second surface; cooling the substrate forming the second protective layer, the cooling temperature is less than 20°C, and the cooling time is 3 seconds to 5 seconds. In this embodiment, the sodium dodecyl sulfate solution, as a surfactant, can form an effective anti-fouling barrier on the side of the substrate, which can reduce the chance of debris or other contaminants generated during the thinning process adhering to the side of the substrate; cooling the substrate forming the second protective layer, especially at a temperature below 20°C, can quickly remove the heat generated during the thinning process. Rapid cooling can not only speed up the process flow, but also avoid the uneven thickness of the wax layer due to slow cooling, further improving the thickness uniformity of the substrate after thinning.
[0043] Specifically, the substrate on which the second protective layer is formed is rapidly cooled, thereby preventing the problem of uneven thickness of the wax layer caused by slow flow of the wax liquid.
[0044] Specifically, the weight ratio of the concentration of sodium lauryl sulfate in the sodium lauryl sulfate solution is 3%-5% (ie, sodium lauryl sulfate accounts for 3%-5% of the sodium lauryl sulfate solution).
[0045] Specifically, with the aid of the sodium lauryl sulfate active agent solution, a protective film can be formed on the side of the substrate to prevent debris from being adsorbed onto the side of the substrate along with the wax liquid during subsequent unloading.
[0046] In some further optional schemes of the present application, after the second surface of the substrate pasted on the substrate is thinned, before the thinned substrate is separated from the substrate, the thinning process of the substrate in the light-emitting diode also includes: attaching dust-free paper to the side of the substrate, the dust-free paper is in contact with the side and has no gaps, the dust-free paper includes a dust-free paper body and a through hole running through the dust-free paper body in a first direction, the first direction is perpendicular to the direction of the plane where the surface of the dust-free paper body is located, and the side is all the surfaces of the substrate except the first surface and the second surface; placing a heating block on the second surface of the portion to heat the wax layer on the edge of the first surface so that the heated wax layer melts and falls on the dust-free paper, wherein the heating block includes a heating block body and a through hole running through the heating block body in a second direction, the second direction is perpendicular to the direction of the plane where the surface of the heating block body is located. In this embodiment, the use of heating blocks and dust-free paper adsorption is mainly to remove the wax layer rich in high-concentration thinning debris at the edge of the substrate before formally unloading, so as to prevent it from diffusing to the surface of the substrate and causing contamination during subsequent formal unloading, further ensuring a high yield of the finished product.
[0047] Specifically, a heating block is placed on a portion of the second surface, where the second surface refers to the edge region of the second surface, i.e., a portion of the second surface extending inward from the edge of the second surface by no more than W millimeters. In actual application, those skilled in the art can set the value of W based on empirical values or obtain it through multiple experiments, and this application does not impose any specific restrictions on this. In the embodiments of this application, the value of W is 1.
[0048] Specifically, a layer of flat dust-free paper is laid on the side of the substrate, and the dust-free paper is in complete contact with the side of the substrate without any gap, warp or bend.
[0049] In other embodiments, the heating block is heated at a temperature of 130°C to 150°C, and the heating time of the heating block is 5 seconds to 10 seconds. In this embodiment, the setting of the heating time and heating temperature ensures that the wax layer at the edge is completely melted, while avoiding deformation or damage to the substrate due to overheating.
[0050] In some further optional solutions of the present application, the substrate is cylindrical in shape, the heating block is annular in shape, the annular thickness of the heating block is 1 mm to 2 mm, the outer diameter of the heating block is no larger than the outer diameter of the substrate, and the difference between the outer diameter of the substrate and the outer diameter of the heating block is no larger than 1 mm. In this embodiment, the use of the annular heating block can concentrate and evenly distribute heat in a specific edge area of the substrate. Since the difference between the outer diameter of the heating block and the outer diameter of the substrate is controlled within an extremely small range, this ensures a close fit between the heating block and the edge area, thereby achieving precise heating of the edge wax layer, avoiding unnecessary energy loss and unnecessary heating of other areas of the substrate, and improving heating efficiency and the accuracy of temperature control.
[0051] Specifically, the substrate is cylindrical, the heating block is annular, and the dust-free paper is annular. Specifically, the annular thickness is the difference between the outer radius and the inner radius of the annular structure.
[0052] Figure 4 Schematic diagram of the top view of heating and melting the wax layer at the edge of the substrate. Figure 4 As shown, the substrate is placed on a platform, a layer of flat dust-free paper is laid on the side of the substrate, and then an annular heating block is placed on the edge area of the second surface of the substrate to heat and melt the wax on the edge of the substrate.
[0053] In other embodiments, after placing a heating block on a portion of the second surface and before separating the thinned substrate from the base plate, the thinning process of the substrate in the light-emitting diode further includes: removing the heating block, removing the dust-free paper, and cleaning the substrate together with the base plate with acetone and ethanol in sequence after the substrate cools naturally.
[0054] According to further exemplary embodiments of the present application, after the substrate is dewaxed and cleaned, the substrate thinning process for the light-emitting diode further includes cleaning the substrate with a sodium hydroxide solution. In this embodiment, the sodium hydroxide solution can effectively remove residual protective layer material on the substrate surface, ensuring the cleanliness of the substrate surface and preventing the residue from affecting subsequent processing or the performance of the LED device.
[0055] Specifically, the substrate is removed from the base plate using a conventional heating unloading process.
[0056] Specifically, the substrate is subjected to conventional wax removal and cleaning, and then cleaned with sodium hydroxide solution and pure water. The mass concentration of the sodium hydroxide solution is 5%-15%, and the cleaning time of the sodium hydroxide solution is 3 minutes to 5 minutes.
[0057] The following provides two specific thinning processes for substrates in light-emitting diodes (Examples 1 and 2) of this application, as well as a prior art thinning process for substrates in light-emitting diodes (Comparative Example 1). This application also provides Examples 3 and 4, Comparative Examples 2 and 3, specifically addressing the scope of pre-thinning.
[0058] Example 1
[0059] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 2.3 degrees, a treatment range of 1.8 mm inward from the edge of the substrate, and a particle size of the thinning medium of 6.5 microns, and then clean it;
[0060] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 78° C., and then rotating the substrate at a high speed of 600 rpm for 42 seconds;
[0061] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 105°C;
[0062] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.25 times the area of the substrate (in square centimeters). Let it stand for 15 seconds.
[0063] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.32Mpa and hold for 18 seconds;
[0064] 6) Edge treatment: spray a 3.8% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 52 seconds;
[0065] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 10 ° C, and the cooling time is 5 seconds;
[0066] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0067] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 138°C, the ring thickness of the heating block is 2 mm, the heating time is 8 seconds, and the outer diameter of the heating block is 0.5 mm away from the outer diameter of the substrate;
[0068] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0069] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0070] 12) Secondary cleaning: After conventional wax removal cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 8%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 3.5 minutes.
[0071] Example 2
[0072] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 1.2 degrees, a treatment range of 1.5 mm inward from the edge of the substrate, and a particle size of the thinning medium of 8 microns, and then clean it;
[0073] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 72° C., and then rotating the substrate at a high speed of 760 rpm for 35 seconds;
[0074] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 108°C;
[0075] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.29 times the area of the substrate (in square centimeters). Let it stand for 18 seconds.
[0076] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.37 MPa and hold for 12 seconds;
[0077] 6) Edge treatment: spray a 4.5% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 44 seconds;
[0078] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 15 ° C, and the cooling time is 3.5 seconds;
[0079] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0080] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 145°C, the ring thickness of the heating block is 1.5 mm, the heating time is 6 seconds, and the outer diameter of the heating block is 0.8 mm away from the outer diameter of the substrate;
[0081] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0082] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0083] 12) Secondary cleaning: After conventional dewaxing cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 12%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 4 minutes.
[0084] Example 3
[0085] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 2.3 degrees, a treatment range of 1 mm inward from the edge of the substrate, and a particle size of the thinning medium of 6.5 microns, and then clean it;
[0086] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 78° C., and then rotating the substrate at a high speed of 600 rpm for 42 seconds;
[0087] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 105°C;
[0088] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.25 times the area of the substrate (in square centimeters). Let it stand for 15 seconds.
[0089] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.32Mpa and hold for 18 seconds;
[0090] 6) Edge treatment: spray a 3.8% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 52 seconds;
[0091] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 10 ° C, and the cooling time is 5 seconds;
[0092] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0093] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 138°C, the ring thickness of the heating block is 2 mm, the heating time is 8 seconds, and the outer diameter of the heating block is 0.5 mm away from the outer diameter of the substrate;
[0094] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0095] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0096] 12) Secondary cleaning: After conventional wax removal cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 8%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 3.5 minutes.
[0097] Example 4
[0098] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 2.3 degrees, a treatment range of 3 mm inward from the edge of the substrate, and a particle size of the thinning medium of 6.5 microns, and then clean it;
[0099] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 78° C., and then rotating the substrate at a high speed of 600 rpm for 42 seconds;
[0100] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 105°C;
[0101] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.25 times the area of the substrate (in square centimeters). Let it stand for 15 seconds.
[0102] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.32Mpa and hold for 18 seconds;
[0103] 6) Edge treatment: spray a 3.8% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 52 seconds;
[0104] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 10 ° C, and the cooling time is 5 seconds;
[0105] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0106] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 138°C, the ring thickness of the heating block is 2 mm, the heating time is 8 seconds, and the outer diameter of the heating block is 0.5 mm away from the outer diameter of the substrate;
[0107] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0108] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0109] 12) Secondary cleaning: After conventional wax removal cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 8%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 3.5 minutes.
[0110] Comparative Example 1
[0111] Use conventional waxing patches, apply the wax liquid directly on the substrate, then stick the substrate on the substrate, solidify the wax by conventional tap water cooling, and thin it by a 600-mesh grinding wheel. After thinning, perform conventional cleaning, then heat and remove the sheet, dewax the waxed substrate, clean it, and dry it to complete the thinning.
[0112] Comparative Example 2
[0113] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 2.3 degrees, a treatment range of 0.5 mm inward from the edge of the substrate, and a particle size of the thinning medium of 6.5 microns, and then clean it;
[0114] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 78° C., and then rotating the substrate at a high speed of 600 rpm for 42 seconds;
[0115] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 105°C;
[0116] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.25 times the area of the substrate (in square centimeters). Let it stand for 15 seconds.
[0117] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.32Mpa and hold for 18 seconds;
[0118] 6) Edge treatment: spray a 3.8% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 52 seconds;
[0119] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 10 ° C, and the cooling time is 5 seconds;
[0120] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0121] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 138°C, the ring thickness of the heating block is 2 mm, the heating time is 8 seconds, and the outer diameter of the heating block is 0.5 mm away from the outer diameter of the substrate;
[0122] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0123] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0124] 12) Secondary cleaning: After conventional wax removal cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 8%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 3.5 minutes.
[0125] Comparative Example 3
[0126] 1) Pretreatment: Pre-thin the edge of the substrate to be thinned, with a thinning angle of 2.3 degrees, a treatment range of 3.5 mm inward from the edge of the substrate, and a particle size of the thinning medium of 6.5 microns, and then clean it;
[0127] 2) Making a first protective layer: coating a layer of monolauryl phosphate on a first surface of the substrate, heating the substrate to 78° C., and then rotating the substrate at a high speed of 600 rpm for 42 seconds;
[0128] 3) Heating: Place the front side of the substrate (the front side of the substrate is the first surface of the substrate) upward on a heating table and heat and keep warm at a temperature of 105°C;
[0129] 4) Waxing: Use high-temperature atomization spraying to evenly spray the melted liquid wax on the first surface of the substrate. The spraying amount (in milliliters) is 0.25 times the area of the substrate (in square centimeters). Let it stand for 15 seconds.
[0130] 5) Patching: Press the substrate vertically downward from the top of the substrate to the substrate with a downward pressure of 0.32Mpa and hold for 18 seconds;
[0131] 6) Edge treatment: spray a 3.8% by weight sodium lauryl sulfate solution onto the side of the substrate and keep it there for 52 seconds;
[0132] 7) Rapid cooling: Use rapid cooling to quickly stick the substrate on the base plate, the cooling temperature is 10 ° C, and the cooling time is 5 seconds;
[0133] 8) Substrate thinning: Thin the substrate according to the normal thinning process, and then clean the substrate and base plate;
[0134] 9) One-time wax removal: Place a flat layer of dust-free paper on the side of the substrate, then place a ring-shaped heating block on the edge of the second surface of the substrate to heat and melt the wax on the edge of the substrate. The heating temperature of the heating block is 138°C, the ring thickness of the heating block is 2 mm, the heating time is 8 seconds, and the outer diameter of the heating block is 0.5 mm away from the outer diameter of the substrate;
[0135] 10) Primary cleaning: Remove the heating block, remove the dust-free paper, and after cooling naturally, clean the treated substrate and the base plate with acetone and ethanol in sequence;
[0136] 11) Secondary dewaxing: remove the substrate from the base plate using conventional heating and unloading process;
[0137] 12) Secondary cleaning: After conventional wax removal cleaning, the substrate is cleaned with a sodium hydroxide solution having a mass concentration of 8%, and finally cleaned with pure water. The cleaning time of the sodium hydroxide solution is 3.5 minutes.
[0138] Comparison of process effects: 100 substrates were processed using Example 1, Example 2, Example 3, Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. The substrate cracking rate (as long as the substrate is cracked, it is considered a crack, the smaller the value, the better) and substrate thickness uniformity (the difference between the maximum and minimum thicknesses of the entire substrate, in microns, the smaller the value, the better) under several treatment methods were counted. The results are shown in Table 1.
[0139] Table 1
[0140]
[0141] As can be seen from Table 1, compared with the prior art, the substrate thinning process in the light-emitting diode of the present application is used to thin the substrate, and the thickness uniformity of the thinned substrate is better and the crack rate is lower. In addition, when the processing range of the pre-thinning treatment is 1 mm to 3 mm extending inward from the edge of the second surface of the substrate, the thickness of the substrate after thinning is more uniform and the crack rate is also smaller.
[0142] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus the necessary general hardware platform, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method.
[0143] An embodiment of the present application further provides a light-emitting diode, which is manufactured by using a thinning process for a substrate in any light-emitting diode.
[0144] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:
[0145] In the thinning process of the substrate in the light-emitting diode of the present application, the edge of the second surface of the substrate is first pre-thinned to ensure that the difference between the edge thickness and the center thickness of the substrate after the pre-thinning treatment is small, thereby ensuring that the thickness of the wax layer applied to the first surface of the substrate after the pre-thinning treatment is relatively uniform, that is, the unevenness of the wax layer after patching caused by the difference in thickness of the substrate edge is reduced, and the thickness of the substrate after subsequent thinning treatment is relatively uniform, thereby reducing the local stress unevenness of the substrate caused by thermal expansion, cooling, machining or microstructural differences due to uneven thickness, thereby maintaining the relative uniformity of the stress distribution inside the substrate, reducing the cracks caused by excessive local stress, ensuring a low crack rate of the substrate, and ensuring a high yield of the substrate.
[0146] The above is a detailed introduction to the substrate thinning process for light-emitting diodes provided by this application. This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. It should be noted that for ordinary technicians in this technical field, without departing from the principles of this application, various improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of the claims of this application.
Claims
1. A thinning process for a substrate in a light-emitting diode, characterized in that: include: providing a substrate having opposing first and second surfaces; Performing a pre-thinning process on the edge of the second surface, wherein the pre-thinning process has a processing range extending inward from the edge of the second surface by 1 mm to 3 mm; forming a wax layer on the first surface; pressing a substrate toward the wax layer so that the base material adheres to the substrate; performing a thinning process on the second surface of the base material adhered to the substrate; The substrate after the thinning process is separated from the base plate, and the substrate is dewaxed and cleaned.
2. The thinning process for the substrate in the light emitting diode according to claim 1, characterized in that: Forming a wax layer on the first surface comprises: The melted liquid wax is sprayed onto the first surface by a high-temperature atomizing spraying method and allowed to stand for 10 to 20 seconds to obtain the wax layer, wherein the temperature in the high-temperature atomizing spraying method is the temperature at which the wax is converted from solid to liquid.
3. The thinning process for the substrate in the light emitting diode according to claim 1, characterized in that: The thinning angle of the pre-thinning treatment is 1 degree to 3 degrees, and the thinning angle represents the angle between the thinning medium and the second surface. The particle size of the thinning medium is less than 10 microns, and the thinning medium represents the medium used to grind or grind the substrate in the pre-thinning treatment.
4. The thinning process for a substrate in a light-emitting diode according to claim 1, characterized in that: After pre-thinning the edge of the second surface and before forming the wax layer on the first surface, the thinning process of the substrate in the light-emitting diode further includes: Monolauryl phosphate is applied to the first surface, and the substrate coated with the monolauryl phosphate is heated to 70° C.-80° C., and the heated substrate is controlled to rotate for 30-50 seconds at a rotation speed of 500 rpm-800 rpm to form a first protective layer on the first surface.
5. The thinning process for the substrate in the light emitting diode according to claim 1, characterized in that: Pressing the substrate toward the wax layer comprises: placing the substrate on a table so that the second surface is in contact with the table; The substrate is pressed vertically downward toward the substrate from directly above the base material, and the pressing is maintained for 10 seconds to 20 seconds at a pressure of 0.3 MPa to 0.4 MPa.
6. The thinning process for the substrate in the light emitting diode according to claim 5, characterized in that: After the substrate is pressed vertically downward toward the substrate from directly above the base material and held for 10 to 20 seconds, and before the second surface of the base material attached to the substrate is thinned, the thinning process of the base material in the light-emitting diode further includes: Spraying a sodium lauryl sulfate solution onto the side of the substrate and letting it stand for 30 seconds to 60 seconds to form a second protective layer on the side, wherein the side is all surfaces of the substrate except the first surface and the second surface; The substrate on which the second protective layer is formed is cooled, the cooling temperature is less than 20° C., and the cooling time is 3 seconds to 5 seconds.
7. The thinning process for a substrate in a light-emitting diode according to claim 1, characterized in that: After thinning the second surface of the substrate adhered to the base plate, and before separating the thinned substrate from the base plate, the thinning process of the substrate in the light-emitting diode further includes: A dust-free paper is attached to the side of the substrate, the dust-free paper is in contact with the side without a gap, the dust-free paper includes a dust-free paper body and a through hole that penetrates the dust-free paper body in a first direction, the first direction is perpendicular to the direction of the plane where the surface of the dust-free paper body is located, and the side is all surfaces of the substrate except the first surface and the second surface; A heating block is placed on part of the second surface to heat the wax layer on the edge of the first surface so that the heated wax layer melts and falls on the dust-free paper, wherein the heating block includes a heating block body and a through hole passing through the heating block body in a second direction, and the second direction is perpendicular to the direction of the plane where the surface of the heating block body is located.
8. The thinning process for a substrate in a light-emitting diode according to claim 7, characterized in that: The heating temperature of the heating block is 130° C.-150° C., and the heating time of the heating block is 5 seconds-10 seconds.
9. The thinning process for a substrate in a light-emitting diode according to claim 7, characterized in that: The substrate is cylindrical in shape, the heating block is annular in shape, the annular thickness of the heating block is 1 mm to 2 mm, the outer diameter of the heating block is not greater than the outer diameter of the substrate, and the difference between the outer diameter of the substrate and the outer diameter of the heating block is not greater than 1 mm.
10. The thinning process for a substrate in a light-emitting diode according to claim 7, characterized in that: After the substrate is dewaxed and cleaned, the thinning process of the substrate in the light-emitting diode further includes: cleaning the substrate with a sodium hydroxide solution.