Manufacturing method of light-emitting diode assembly

Abstract

The invention discloses a manufacturing method of a light-emitting diode assembly. The method comprises the following steps: forming a thermal buffer layer with a preset thickness on the surface of a substrate; installing a plurality of LED chips on the thermal buffer layer, and enabling the electrodes of the chips to be in circuit connection with the substrate; carrying out first curing treatment on the thermal buffer layer and the chip; coating a packaging adhesive layer on the surface of the cured thermal buffer layer, wherein the packaging adhesive layer covers all the LED chips; monitoring stress distribution data in the curing process of the packaging adhesive layer in real time through a stress distribution detection device; dynamically adjusting the temperature curve of the second curing treatment, and performing the second curing treatment on the packaging adhesive layer to form a packaging structure; coating a fluorescent layer on the surface of the packaging structure and carrying out third curing; forming an optical lens layer on the surface of the fluorescent layer; and cutting the packaged substrate, and separating the substrate into independent LED assemblies. The light emitting uniformity of the high-density LED assembly is improved, the yield is remarkably improved, and the production cycle does not need to be prolonged or the material reliability does not need to be sacrificed.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing light - emitting diode components, and particularly to a method for manufacturing light - emitting diode components. Background Art

[0002] A light - emitting diode (LED) is an optoelectronic device based on the principle of electroluminescence of semiconductor materials. Its core components consist of a semiconductor chip, packaging materials, electrodes, and an optical structure. The method for manufacturing LED components involves multiple processes such as epitaxial growth, chip preparation, and packaging technology. Among them, the packaging technology directly affects the light efficiency, heat dissipation performance, and device reliability, and is a key technical link determining the performance of LED components. In recent years, with the wide application of high - brightness LEDs in fields such as general lighting and display backlighting, higher requirements have been put forward for the precision and efficiency of component manufacturing processes.

[0003] In current LED component manufacturing technologies, epitaxial wafers are used to grow multi - layer semiconductor structures through metal - organic chemical vapor deposition (MOCVD), chips form electrode patterns through micro - nano processing such as lithography and etching, and in the packaging process, phosphor coating and lens forming are mostly completed by injection molding or dispensing processes. Existing technologies generally use silicone or epoxy resin as packaging substrates, and achieve material forming through thermal curing or ultraviolet curing. At the same time, in the phosphor coating process, methods such as spraying and spin - coating are mostly used to prepare the wavelength - conversion layer. Although existing methods have made progress in improving light efficiency and simplifying the process flow, in high - density chip integration scenarios, thermal stress concentration is likely to occur at the interface between the packaging material and the chip, leading to an increased risk of die - bonding layer cracking. Especially in the process of multi - chip array packaging, due to the difference between the curing shrinkage rate of the packaging material and the thermal expansion coefficient of the chip, the non - uniform stress distribution generated during the curing process will cause the chip position to shift by a micron level. This shift will cause the optical axis to deviate during subsequent optical lens forming, resulting in a light - emitting angle deviation exceeding ±3°, significantly reducing the uniformity of the display module. Attempts in existing processes to alleviate this problem by reducing the curing temperature or extending the curing time often lead to an extended production cycle or insufficient cross - linking degree of the material, making it difficult to balance efficiency and reliability. Therefore, it is necessary to propose a method for manufacturing light - emitting diode components to solve the above problems. Summary of the Invention

[0004] The present invention provides a method for manufacturing light - emitting diode components to solve the problem that in high - density chip integration scenarios, thermal stress concentration is likely to occur at the interface between the packaging material and the chip, leading to an increased risk of die - bonding layer cracking.

[0005] The present invention provides a method for manufacturing light - emitting diode components, including the following steps:

[0006] Step S1: Provide a substrate and form a thermal buffer layer with a predetermined thickness on the surface of the substrate;

[0007] Step S2: Mount a plurality of LED chips on the thermal buffer layer, and connect the chip electrodes to the substrate circuit;

[0008] Step S3: Perform a first curing treatment on the thermal buffer layer and the chips, with a curing temperature of 80 - 100 °C and a curing time of 10 - 30 minutes;

[0009] Step S4: Coat an encapsulation adhesive layer on the surface of the cured thermal buffer layer, and the encapsulation adhesive layer covers all the LED chips;

[0010] Step S5: Use a stress distribution detection device to monitor the stress distribution data during the curing process of the encapsulation adhesive layer in real time;

[0011] Step S6: According to the stress distribution data in Step S5, dynamically adjust the temperature curve of the second curing treatment, so that the curing temperature increases step by step within the range of 120 - 140 °C, and the holding time of each temperature segment is associated with the position of the stress concentration area;

[0012] Step S7: Perform a second curing treatment on the encapsulation adhesive layer to form an encapsulation structure;

[0013] Step S8: Coat a fluorescent layer on the surface of the encapsulation structure and perform a third curing;

[0014] Step S9: Form an optical lens layer on the surface of the fluorescent layer;

[0015] Step S10: Cut the completed encapsulated substrate and separate it into independent LED components.

[0016] Further, the thermal buffer layer in Step S1 is composed of a composite material of silicone rubber and nano-aluminum oxide particles, and the mass ratio of nano-aluminum oxide is 5 - 15%.

[0017] Further, forming the thermal buffer layer in Step S1 includes:

[0018] Mix silicone rubber and nano-aluminum oxide particles into a colloidal mixture;

[0019] Uniformly coat the colloidal mixture on the surface of the substrate by a spraying process;

[0020] Perform a pre-curing treatment on the coated colloidal mixture, with a pre-curing temperature of 60 - 70 °C and a pre-curing time of 5 - 10 minutes.

[0021] Further, in the first curing treatment of Step S3, the temperature rises from 60 °C to the target temperature at a rate of 2 °C / min, and the curing process is carried out in a nitrogen atmosphere.

[0022] Further, the stress distribution detection device described in step S5 includes an infrared thermal imaging module and a laser displacement sensor. The temperature gradient distribution of the encapsulation adhesive layer is obtained through the infrared thermal imaging module, and the chip position offset is detected in combination with the laser displacement sensor to generate stress distribution data.

[0023] Further, adjusting the temperature curve in step S6 includes: when the detected chip offset exceeds 0.5 μm, the curing temperature of the corresponding area is reduced by 10 - 15 °C, and the holding time in this area is extended by 20 - 30 seconds.

[0024] Further, coating the fluorescent layer in step S8 includes: mixing phosphor and silica gel in a mass ratio of 1:3 to form a fluorescent colloid, and covering the surface of the encapsulation structure with the fluorescent colloid through a screen printing process.

[0025] Further, the third curing process in step S8 includes:

[0026] Curing the fluorescent layer at 80 °C for 10 minutes;

[0027] Raising the temperature to 110 °C and continuing to cure for 20 minutes;

[0028] After the curing is completed, cooling down to room temperature at a rate of 1 °C / min.

[0029] Further, the material of the optical lens layer in step S9 is polydimethylsiloxane, its refractive index is 1.41 - 1.43, and the lens curvature radius is inversely proportional to the chip pitch.

[0030] Further, the cutting process in step S10 adopts laser stealth cutting technology, the laser wavelength is 355 nm, and the cutting depth is 90 - 95% of the substrate thickness.

[0031] The present invention has the following beneficial effects: By combining the thermal buffer layer with dynamically adjusting the curing parameters, the present invention significantly reduces the non-uniform stress caused by the material shrinkage difference during the encapsulation process, controls the chip position offset within 0.5 μm, thereby avoiding the light output angle deviation caused by the deviation of the optical axis; The staged curing process improves the encapsulation efficiency while ensuring the interfacial bonding strength between the fluorescent layer and the optical lens, improves the light output uniformity of the high-density LED component, significantly improves the yield, and does not require extending the production cycle or sacrificing the material reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1Flow chart of a method for manufacturing a light emitting diode component provided by the present invention. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The technical solutions provided by each embodiment of the present invention will be described in detail below with reference to the drawings.

[0035] Please refer to Figure 1 , a method for manufacturing a light emitting diode component provided by an embodiment of the present invention, including the following steps:

[0036] Step S1: Provide a substrate and form a thermal buffer layer with a predetermined thickness on the surface of the substrate.

[0037] Specifically, the thermal buffer layer is composed of a composite material of silicone rubber and nano-aluminum oxide particles, where the mass ratio of nano-aluminum oxide is 5-15%. Forming the thermal buffer layer includes: mixing silicone rubber and nano-aluminum oxide particles into a colloidal mixture; uniformly coating the colloidal mixture on the surface of the substrate through a spraying process; performing pre-curing treatment on the coated colloidal mixture, with the pre-curing temperature being 60-70°C and the pre-curing time being 5-10 minutes.

[0038] This step combines the flexibility of silicone rubber and the high thermal conductivity of nano-aluminum oxide to form an intermediate layer with both stress buffering and heat diffusion functions. The addition ratio of nano-aluminum oxide particles is optimized, which can not only improve the material rigidity to inhibit shrinkage deformation, but also avoid excessive addition resulting in an increase in the brittleness of the coating. The spraying process ensures that the colloidal mixture forms a uniformly thick coating on the surface of the substrate, and the pre-curing treatment preliminarily crosslinks the surface layer, which not only prevents the coating from flowing during subsequent chip installation, but also retains the fluidity of the underlying material to release stress during the subsequent high-temperature curing stage.

[0039] Step S2: Install a plurality of LED chips on the thermal buffer layer and connect the chip electrodes to the substrate circuit.

[0040] The pre-cured surface hardness of the thermal buffer layer provides a stable support interface for chip installation. Combining with the positioning of a high-precision die bonder, the chip array pitch error can be controlled within ±1μm. The electrodes are connected by gold wire bonding or conductive adhesive. The low coefficient of thermal expansion of the thermal buffer layer reduces the thermal mismatch stress between the chip and the substrate and avoids solder joint cracking.

[0041] Step S3: Perform the first curing process on the thermal buffer layer and the chip. The curing temperature is 80 - 100 °C, and the curing time is 10 - 30 minutes.

[0042] Specifically, during the first curing process, the temperature is increased from 60 °C to the target temperature at a rate of 2 °C / min, and the curing process is carried out in a nitrogen atmosphere.

[0043] The slow temperature increase allows the silicone rubber molecular chains to fully stretch and uniformly combine with the nanoparticles, avoiding the accumulation of internal stress caused by rapid curing. The nitrogen atmosphere isolates oxygen and prevents the formation of microcracks on the surface of the silicone rubber. The curing at this stage fully crosslinks the thermal buffer layer, improves its thermal conductivity, and preliminarily locks the position of the chip, with an offset less than 0.2 μm.

[0044] Step S4: Coat an encapsulation adhesive layer on the surface of the cured thermal buffer layer. The encapsulation adhesive layer covers all LED chips.

[0045] The encapsulation adhesive layer uses high-transmittance silica gel with a transmittance ≥ 95%. It covers the chip surface through a dispensing process, and the thickness is controlled within 100 - 150 μm to balance optical performance and structural strength. The low-viscosity characteristic of the encapsulation adhesive layer ensures its natural leveling to fill the chip gaps, avoiding light scattering caused by residual bubbles.

[0046] Step S5: Use a stress distribution detection device to monitor the stress distribution data during the curing process of the encapsulation adhesive layer in real time.

[0047] Specifically, the stress distribution detection device includes an infrared thermal imaging module and a laser displacement sensor. The temperature gradient distribution of the encapsulation adhesive layer is obtained through the infrared thermal imaging module, and the chip position offset is detected in combination with the laser displacement sensor to generate stress distribution data.

[0048] The infrared thermal imaging module captures the temperature difference of each region of the encapsulation adhesive layer with a temperature resolution of 0.1 °C, and the laser displacement sensor monitors the dynamic change of the chip position with an accuracy of 0.1 μm. A real-time stress distribution map is generated through a data fusion algorithm, which can predict the stress concentration area 5 - 10 seconds in advance and provide a decision-making basis for dynamic regulation.

[0049] Step S6: According to the stress distribution data in Step S5, dynamically adjust the temperature curve of the second curing process so that the curing temperature increases step by step within the range of 120 - 140 °C, and the holding time of each temperature segment is associated with the position of the stress concentration area.

[0050] Specifically, adjusting the temperature curve includes: when the detected chip offset exceeds 0.5 μm, reduce the curing temperature of the corresponding area by 10 - 15 °C and extend the holding time in this area by 20 - 30 seconds.

[0051] The dynamic regulation is based on the PID control algorithm. When the local chip offset exceeds the threshold, the temperature in this area is reduced by 10 - 15 °C to slow down the curing rate, and the holding time is extended by 20 - 30 seconds to allow the material to relax sufficiently. This method reduces the shrinkage rate of the overall encapsulation adhesive layer from 2.5% in the traditional process to 0.8%, and optimizes the standard deviation of the chip offset from 1.2 μm to 0.4 μm.

[0052] Step S7: Perform a second curing treatment on the encapsulation adhesive layer to form an encapsulation structure.

[0053] The temperature increases in stages, from 120 °C to 130 °C and then to 140 °C, causing the encapsulation adhesive layer to crosslink in a gradient from the inside out. The inner layer cures rapidly to form a support framework, and the outer layer cures slowly to release residual stress. The glass transition temperature of the final encapsulation structure is increased to above 150 °C to ensure no warping and deformation under high-temperature environments.

[0054] Step S8: Coat a fluorescent layer on the surface of the encapsulation structure and perform a third curing.

[0055] Specifically, coating the fluorescent layer includes: mixing phosphor powder and silica gel in a mass ratio of 1:3 to form a fluorescent colloid, and covering the surface of the encapsulation structure with the fluorescent colloid through a screen printing process.

[0056] The third curing treatment includes: curing the fluorescent layer at 80 °C for 10 minutes; raising the temperature to 110 °C and continuing to cure for 20 minutes; after curing is completed, cooling to room temperature at a rate of 1 °C / min. The 1:3 ratio of phosphor powder to silica gel ensures a wavelength conversion efficiency of ≥90%, and the screen printing process enables the thickness uniformity of the fluorescent layer to be within ±3%. Staged curing avoids agglomeration of phosphor powder due to sudden temperature changes, and the slow cooling rate of 1 °C / min reduces the thermal stress at the interface between silica gel and the fluorescent layer, controlling the color temperature consistency deviation within ±50 K.

[0057] Step S9: Form an optical lens layer on the surface of the fluorescent layer.

[0058] Specifically, the material of the optical lens layer is polydimethylsiloxane, its refractive index is 1.41 - 1.43, and the lens curvature radius is inversely proportional to the chip pitch. The refractive index of polydimethylsiloxane forms a gradient optical interface with the fluorescent layer, reducing total reflection loss.

[0059] Step S10: Cut the completed encapsulated substrate to separate it into independent LED components.

[0060] Specifically, the cutting process uses laser stealth cutting technology with a laser wavelength of 355 nm and a cutting depth of 90 - 95% of the substrate thickness. The 355 nm ultraviolet laser forms a modified layer inside the substrate through the multi - photon absorption effect. The cutting depth is controlled within 90 - 95% of the substrate thickness, which not only ensures the reliability of mechanical breaking but also avoids damaging the internal circuit. After cutting, the component can meet the assembly requirements of the high - precision display module without secondary polishing.

[0061] The embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention.

Claims

1. A method for manufacturing a light-emitting diode component, characterized in that, It includes the following steps: Step S1: Provide a substrate and form a thermal buffer layer with a predetermined thickness on the surface of the substrate; Step S2: Mount a plurality of LED chips on the thermal buffer layer and connect the chip electrodes to the substrate circuit; Step S3: Perform a first curing treatment on the thermal buffer layer and the chips, with a curing temperature of 80 - 100 °C and a curing time of 10 - 30 minutes; Step S4: Coat an encapsulation glue layer on the surface of the cured thermal buffer layer, and the encapsulation glue layer covers all LED chips; Step S5: Real-time monitor the stress distribution data during the curing process of the encapsulation glue layer through a stress distribution detection device; Step S6: According to the stress distribution data in Step S5, dynamically adjust the temperature curve of the second curing treatment, so that the curing temperature increases step by step within the range of 120 - 140 °C, and the holding time of each section of temperature is associated with the position of the stress concentration area; Step S7: Perform a second curing treatment on the encapsulation glue layer to form an encapsulation structure; Step S8: Coat a fluorescent layer on the surface of the encapsulation structure and perform a third curing; Step S9: Mold an optical lens layer on the surface of the fluorescent layer; Step S10: Cut the substrate after encapsulation is completed and separate it into independent LED components.

2. The manufacturing method of a light-emitting diode component according to claim 1, characterized in that The thermal buffer layer described in Step S1 is composed of a composite material of silicone rubber and nano-aluminum oxide particles, where the mass ratio of nano-aluminum oxide is 5 - 15%.

3. The manufacturing method of a light emitting diode component according to claim 2, wherein Forming the thermal buffer layer in Step S1 includes: Mix silicone rubber and nano-aluminum oxide particles into a colloidal mixture; Evenly coat the colloidal mixture on the surface of the substrate through a spraying process; Perform a pre-curing treatment on the coated colloidal mixture, with a pre-curing temperature of 60 - 70 °C and a pre-curing time of 5 - 10 minutes.

4. A method for manufacturing a light emitting diode component according to claim 3, characterized in that, In the first curing treatment of Step S3, the temperature rises from 60 °C to the target temperature at a rate of 2 °C / min, and the curing process is carried out in a nitrogen atmosphere.

5. A method for manufacturing a light-emitting diode component according to claim 1, wherein The stress distribution detection device described in Step S5 includes an infrared thermal imaging module and a laser displacement sensor. Obtain the temperature gradient distribution of the encapsulation glue layer through the infrared thermal imaging module, and combine the laser displacement sensor to detect the chip position offset amount to generate stress distribution data.

6. A method for manufacturing a light-emitting diode component according to claim 5, characterized in that, Adjusting the temperature curve in Step S6 includes: when the detected chip offset amount exceeds 0.5 μm, reduce the curing temperature of the corresponding area by 10 - 15 °C and extend the holding time in this area by 20 - 30 seconds.

7. A method for manufacturing a light-emitting diode component according to claim 1, characterized in that Coating the fluorescent layer in Step S8 includes: Mix phosphor and silica gel in a mass ratio of 1:3 to form a fluorescent colloid, and cover the surface of the encapsulation structure with the fluorescent colloid through a screen printing process.

8. A method for manufacturing a light emitting diode component according to claim 7, characterized in that, The third curing treatment in Step S8 includes: Cure the fluorescent layer at 80 °C for 10 minutes; Raise the temperature to 110 °C and continue to cure for 20 minutes; After curing is completed, cool down to room temperature at a rate of 1 °C / min.

9. A method for manufacturing a light-emitting diode component according to claim 1, wherein The material of the optical lens layer described in Step S9 is polydimethylsiloxane, its refractive index is 1.41 - 1.43, and the lens curvature radius is inversely proportional to the chip pitch.

10. A method for manufacturing a light-emitting diode component according to claim 1, characterized in that, In Step S10, the cutting process uses laser stealth cutting technology, the laser wavelength is 355 nm, and the cutting depth is 90 - 95% of the substrate thickness.

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