CN117334795A - Preparation and application of high-power LED packaging structure based on ceramic surrounding dam - Google Patents

Abstract

The invention relates to the field of high-power LED packaging, specifically the preparation and application of a high-power LED packaging structure based on ceramic dams. In this invention, the uppermost ceramic tile is laser-cut to cut out an array of through holes, and solder or soldering flakes are coated on the lower surface of the uppermost ceramic tile or the upper and lower surfaces of non-topmost ceramic tiles; according to the ceramic tile through-hole layer-copper layer - Ceramic tile layer - Copper layer sequence, arrange the porcelain tiles and copper flakes from top to bottom to make the parts to be sintered; use the AMB process for vacuum active brazing and sintering, and then perform wire cutting to make the ceramic dam cladding Copper substrate: Attach soldering pieces and chips to the substrate, sinter them by hot pressing, and pour epoxy resin for solidification. Finally, wires are welded to both ends of the next copper sheet, and the power is turned on, and the LED chip emits light. Through the above preparation steps, the present invention can improve the performance and reliability of the LED packaging structure.

Description

Preparation and application of a high-power LED packaging structure based on ceramic dam

The invention relates to the field of high-power LED packaging, specifically the preparation and application of a high-power LED packaging structure based on ceramic dams.

Background technique

As power devices increasingly require higher power output, heat conduction becomes critical. In the face of high-power LED light-emitting devices used in daily life, copper-clad ceramic substrates are particularly important as the heat dissipation core of power devices.

However, when traditional welding methods are used for welding, virtual welding often occurs, and the structural process of welding the dam is also relatively complex. There are at least the following problems in the prior art:

1. Poor welding effect: The welding effect between the substrate and the high-power chip is not good, and it is easy to have weak soldering, falling off, etc.;

2. Multiple processes: Traditional welding methods require multiple processes to make the dam required for the substrate, resulting in low production efficiency;

3. Complex process: Traditional copper-clad ceramic substrates usually require electroplating metal dams on the substrate to achieve heat dissipation. This process is relatively complex.

Therefore, we propose the preparation and application of a high-power LED packaging structure based on ceramic dams.

Contents of the invention

The purpose of the present invention is to provide a preparation and application of a high-power LED packaging structure based on ceramic dams to solve the problems raised in the above background technology.

In order to solve the above technical problems, the present invention provides the following technical solutions:

The preparation of a high-power LED packaging structure based on ceramic dams includes the following steps:

Step S1: Use laser cutting technology to cut an array of through holes in the ceramic tile to produce a through-hole ceramic tile, and then cut the length of both ends of the through-hole ceramic tile to be 3 to 10 mm smaller than the length of the copper sheet to produce the uppermost layer of porcelain. piece;

Step S2: Coat the upper and lower surfaces of the ceramic plate with solder using a screen printing process to form a solder layer, place a copper sheet on the surface of the solder layer to form a metal layer, and prepare a piece to be sintered;

Step S3: Place pressure heads on the upper and lower surfaces of the parts to be sintered, and use the AMB (brazing) sintering process to perform vacuum active brazing and sintering. The sintering temperature is 600-950°C and the sintering time is 60-480 min. Sintered parts: According to the AMB copper-clad laminate production and processing process, the sintered parts are sequentially subjected to the steps of film sticking, exposure, development, copper etching and solder etching, and strip-shaped grooves are formed on the surface of the copper sheet to obtain a strip-shaped groove etched on the surface. copper sheet;

Step S4: Degrease the surface of the copper sheet with strip grooves etched on the surface prepared in step S3 and the uppermost ceramic sheet prepared in step S1 respectively, and then clean the surfaces respectively, and then remove the through holes of the uppermost ceramic sheet. Align the center with the strip groove center of the copper sheet and sinter to prepare the ceramic copper-clad substrate; after the ceramic copper-clad substrate cools to room temperature, use a metal tungsten wire to parallel to the upper surface of the uppermost ceramic sheet, and Aim at the center of the through hole and perform longitudinal cutting until it reaches the position of the strip groove of the next layer of copper sheet, then end the cutting to obtain a ceramic dam copper-clad substrate;

Step S5: Use cleaning fluid to perform surface treatment on the ceramic dam copper-clad substrate. Attach silver solder tabs to both ends of the strip grooves of the surface-treated ceramic dam copper-clad substrate first, and then attach the chip to ensure that each The positive and negative electrodes of the chip are in the same direction at each dam position, and then hot-pressed and sintered at 200-250°C for 5-30 minutes. Epoxy resin is poured into the through-hole position for solidification. Finally, the positive electrode wire is welded to both ends of the bottom copper sheet. The negative wire is connected to the power source and the LED chip emits light.

Further, in step S1, the ceramic piece is one of Al ₂ O ₃ , AlN, and Si ₃ N ₄ , with a thickness of 0.15 to 1 mm.

Further, the copper sheet in step S1 is surface-treated metal copper without oxide layer, and has a thickness of 0.1 to 0.4 mm.

Further, the thickness of the solder layer in step S2 is 5-15 μm.

Further, the preparation process of the parts to be sintered in step S2 also includes the following situations:

Case 1: Apply active metal solder sheets to the upper and lower surfaces of the ceramic plate respectively, and place a copper sheet on the surface of the metal solder sheets to prepare the parts to be sintered;

Case 2: Coat the lower surface of the uppermost ceramic tile with screen printing solder to form a solder layer. Place a copper sheet on the lower surface of the solder layer, place a ceramic plate on the lower surface of the copper sheet, and place a ceramic plate on the lower surface of the ceramic plate. Place a copper sheet to prepare the part to be sintered;

Case 3: Apply an active metal solder sheet to the lower surface of the top porcelain sheet, place a copper sheet on the lower surface of the metal solder sheet, a ceramic plate on the lower surface of the copper sheet, and a ceramic plate on the lower surface of the ceramic plate. Copper sheets are used to prepare parts to be sintered;

Case 4: Coat the lower surface of the top ceramic tile with solder to form a solder layer. Place a copper sheet on the lower surface of the solder layer. Place a double-sided solder ceramic plate on the lower surface of the copper sheet. Place a copper sheet on the lower surface of the ceramic plate with the welding chip attached to prepare the part to be sintered;

Case 5: Place a solder sheet on the lower surface of the top ceramic tile, place a copper sheet on the lower surface of the solder sheet, place a double-sided solder sheet ceramic plate on the lower surface of the copper sheet, and mount the double-sided solder sheet on the lower surface of the copper sheet. Place a copper sheet on the lower surface of the ceramic plate to prepare the part to be sintered.

Further, in step S3, the indenter is one of glass, ceramic, graphite block, and corundum brick.

Further, the process conditions for copper etching in step S3 are: the mass concentration of copper ions is 2-3g/L, the copper complexing agent is iminodiacetic acid with a mass fraction of 1.5-2.0%, and the mass fraction of hydrogen peroxide is 15-20%, temperature 30-45℃, time 5-25min.

Further, the etching solution for solder etching in step S3 includes: 300-500g/L ferric chloride, 2-3g/L hydrochloric acid, 10-30g/L sodium hypochlorite, 0.05-0.10g/L phenyltriazole, temperature 30-45℃, time 10-25min.

Further, in step S3, the width of the strip grooves is 0.1 to 1 mm, and the spacing between adjacent strip grooves is consistent with the center spacing of the through holes cut by the uppermost ceramic tile.

Further, the solvent used in the surface degreasing process in step S4 is one of ethanol, isopropyl alcohol, and acetone.

Further, a diamond wire cutting machine is used for the cutting process in step S4.

Further, the size of the silver soldering piece in step S5 is determined by the size of the positive and negative poles of the LED chip.

Further, the curing process conditions in step S5 are: curing temperature 80-150°C, curing time 10-60 minutes.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The preparation and application of a high-power LED packaging structure based on a ceramic dam according to the present invention, including the preparation of a four-layer copper-clad ceramic substrate, in which the uppermost ceramic tile is laser-cut to cut out an array of through holes. Coat the lower surface of the tile or the upper and lower surfaces of the non-top ceramic tile with solder or soldering flakes, and then place the ceramic tiles and copper flakes from top to bottom in the order of ceramic tile through-hole layer-copper layer-ceramic tile layer-copper layer. Arrange them to prepare the parts to be sintered; place indenter on the upper and lower parts of the parts to be sintered, and use the AMB process to perform vacuum active brazing and sintering, so that the ceramic tiles and copper flakes are firmly bonded together. A tungsten wire is used to cut the uppermost ceramic layer and the next copper layer to obtain a ceramic dam copper-clad substrate; through the above preparation steps, the present invention mainly solves the problems of poor heat dissipation, high cost, complex process, and efficiency of the welding layer in the traditional welding method. Low question.

2. The preparation and application of a high-power LED packaging structure based on ceramic dams of the present invention provides a new LED silver sheet welding method, which effectively solves the problems of weak soldering and falling off that are easy to occur in traditional welding methods. The stability and reliability of the welding effect are improved; the invention adopts a four-layer structure of copper-clad substrate and sintered ceramic dam, which simplifies the manufacturing process and improves production efficiency; the invention provides a high-power heat dissipation substrate that can be directly filled with glue. The structural process is simplified and the manufacturing cost is reduced; the present invention provides a flip-chip LED current transfer mode without gold wires, which changes the way gold wires transfer current in the traditional LED packaging structure and improves the current transfer efficiency and reliability.

Description of drawings

The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. In the attached picture:

Figure 1 is a diagram of the uppermost ceramic tile of the ceramic copper-clad substrate of the present invention;

Figure 2 is a front view of the ceramic copper-clad substrate to be sintered according to the present invention;

Figure 3 is a left side view of the ceramic copper-clad substrate of the present invention;

Figure 4 is a schematic cross-sectional view of the ceramic dam copper-clad substrate of the present invention;

Figure 5 is a three-dimensional structural view of the ceramic dam copper-clad substrate of the present invention;

Figure 6 is a structural diagram of the ceramic dam copper-clad substrate of the present invention;

Figure 7 is a structural diagram of the positive and negative electrode packages of the ceramic dam copper-clad substrate of the present invention (chips are not soldered);

Figure 8 is a structural diagram of the ceramic dam copper-clad substrate chip welding package of the present invention (chip has been welded);

Figure 9 is a top view of the ceramic dam copper-clad substrate chip welding package of the present invention (the chip has been welded);

In the picture: 101: the top ceramic tile, 102: ceramic plate, 103: copper sheet, 104: strip groove, 301: positive electrode, 302: negative electrode, 303: chip.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all 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.

Example 1: Preparation of a high-power LED packaging structure based on ceramic dam, including the following steps:

Step S1: Use laser cutting technology to cut an array of through holes in the ceramic tile to produce a through-hole ceramic tile, and then cut the length of both ends of the through-hole ceramic tile to be 3 mm smaller than the length of the copper sheet to produce the uppermost ceramic tile 101 ;

Step S2: Coat the upper and lower surfaces of the ceramic plate 102 with solder using a screen printing process to form a solder layer, place a copper sheet 103 on the surface of the solder layer to form a metal layer, and prepare a piece to be sintered;

Step S3: Place pressure heads on the upper and lower surfaces of the parts to be sintered, and use the AMB sintering process for vacuum active brazing and sintering. The sintering temperature is 600°C and the sintering time is 60 minutes to obtain the sintered parts; produce them according to the AMB copper-clad laminate In the processing flow, the sintered parts are sequentially subjected to the steps of film sticking, exposure, development, copper etching and solder etching to form strip grooves on the surface of the copper sheet 103, thereby producing the copper sheet 103 with the strip grooves 104 etched on the surface;

Step S4: Degrease the surface of the copper sheet 103 with strip grooves 104 etched on the surface and the uppermost ceramic tile 101 prepared in step S1. The center of the through hole 101 is aligned with the center of the strip groove 104 of the copper sheet 103, and sintering is performed to obtain a ceramic copper-clad substrate; after the substrate is cooled to room temperature, wire cutting is performed, using a metal tungsten wire with a thickness of 0.5mm. , cut it parallel to the upper surface of the uppermost ceramic piece 101, and align it with the center of the through hole for longitudinal cutting until it reaches the groove position of the next layer of copper piece 103, then end the cutting to obtain a ceramic dam copper-clad substrate;

Step S5: Use cleaning fluid to perform surface treatment on the ceramic dam copper-clad substrate, first attach silver solder tabs to both ends of the strip groove 104 of the surface-treated ceramic dam copper-clad substrate, and then attach the chip 303. Make sure that the positive and negative electrodes of the chip are in the same direction at each dam position, then hot press and sinter at 200°C for 5 minutes, pour epoxy resin into the through hole position for curing (curing temperature 80°C, curing time 60 minutes), and finally add copper on the bottom layer Weld the positive electrode 301 wire and the negative electrode 303 wire to both ends of the chip 103, turn on the power, and the LED chip emits light.

Example 2: Preparation of a high-power LED packaging structure based on ceramic dam, including the following steps:

Step S1: Use laser cutting technology to cut an array of through holes in the ceramic tile with a diameter of 10mm to produce a through-hole ceramic tile, and then cut the length of both ends of the through-hole ceramic tile to be 1mm smaller than the length of the copper plate to produce a through-hole ceramic tile. Get the top tile 101;

Step S2: Coat the upper and lower surfaces of the ceramic plate 102 with solder using a screen printing process to form a solder layer, place a copper sheet 103 on the surface of the solder layer to form a metal layer, and prepare a piece to be sintered;

Step S3: Place pressure heads on the upper and lower surfaces of the parts to be sintered, and use the AMB sintering process for vacuum active brazing and sintering. The sintering temperature is 950°C and the sintering time is 480 minutes to obtain the sintered parts; produce them according to the AMB copper-clad laminate In the processing flow, the sintered parts are sequentially subjected to the steps of film pasting, exposure, development, copper etching and solder etching to form strip grooves 104 on the surface of the copper sheet 103 to obtain the copper sheet 103 with the strip grooves 104 etched on the surface;

Step S4: Degrease the surface of the copper sheet 104 with strip grooves etched on the surface prepared in step S3 and the uppermost ceramic tile 101 prepared in step S1 respectively, and then perform surface cleaning respectively, and then remove the top ceramic tile 101 The center of the through hole is aligned with the center of the strip groove 104 of the copper sheet 103, and sintering is performed to obtain a substrate; after the substrate is cooled to room temperature, wire cutting is performed, and a metal tungsten wire with a thickness of 1 mm is used to cut it parallel to The upper surface of the uppermost ceramic piece 101 is aligned with the center of the through hole and is cut longitudinally until the groove position of the next layer of copper piece 103 is reached. The cutting is completed to obtain a ceramic dam copper-clad substrate;

Step S5: Use cleaning fluid to perform surface treatment on the ceramic dam copper-clad substrate. Attach silver solder tabs to both ends of the strip groove 104 in the surface-treated ceramic dam copper-clad substrate first, and then attach the chip. 303, ensure that the positive and negative electrodes of the chip are in the same direction at each dam position, then hot press and sinter at 250°C for 30 minutes, pour epoxy resin into the through hole position for curing (curing temperature 150°C, curing time 10 minutes), and finally in the final The two ends of the lower copper sheet 103 are welded with the positive 301 wire and the negative 303 wire, and the power is turned on, and the LED chip emits light;

experiment

Implementation case 1 Implementation case 2 LED brightness changes continuously for 7 days No significant changes No significant changes Substrate operating temperature 30℃ 30℃ Bare chip without substrate operating temperature 40℃ 40℃ Cost comparison of ceramic dams and metal dams reduce reduce Compared with traditional dams, the process difficulty is Simple Simple

Based on the data in the table above, the following conclusions can be clearly drawn:

After continuous operation, the performance of the LED chip has not significantly declined. For multiple high-power LED chips >1W working simultaneously, the copper-clad ceramic substrate can conduct heat in time without affecting the working status of the chip.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations are mutually exclusive. any such actual relationship or sequence exists between them. Furthermore, the terms "comprising," "comprising," or any other variation thereof are intended to cover a non-exclusive inclusion such that a process, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed. , or may also include elements inherent to the process, method, article or equipment.

Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it is still The technical solutions described in the foregoing embodiments may be modified, or some of the technical features may be equivalently replaced. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. Preparation of a high-power LED packaging structure based on ceramic dam, which is characterized by: including the following steps: Step S1: Use laser cutting technology to cut an array of through holes in the ceramic tile to produce a through-hole ceramic tile, and then cut the length of both ends of the through-hole ceramic tile to be 3 to 10 mm smaller than the length of the copper sheet to produce the uppermost layer of porcelain. slice(101); Step S2: Coat the upper and lower surfaces of the ceramic plate (102) with solder using a screen printing process to form a solder layer, place a copper sheet (103) on the surface of the solder layer to form a metal layer, and prepare Parts to be sintered; Step S3: Place indenter on the upper surface and lower surface of the part to be sintered respectively, and use the AMB sintering process to perform vacuum active brazing and sintering. The sintering temperature is 600-950°C and the sintering time is 60-480 min to prepare the sintered part; according to AMB copper-clad laminate production and processing process, the sintered parts are sequentially subjected to the steps of film pasting, exposure, development, copper etching and solder etching to form strip-shaped grooves (104) on the surface of the copper sheet (103) to obtain strip-shaped grooves etched on the surface. The copper sheet (103) of the slot (104); Step S4: Degrease the surface of the copper sheet (103) with strip grooves (104) etched on the surface prepared in step S3 and the top porcelain sheet (101) prepared in step S1 respectively, and then perform surface cleaning respectively. , align the center of the through hole of the uppermost ceramic piece with the center of the strip groove (104) of the copper piece (103), and sinter it to prepare a ceramic copper-clad substrate; after the ceramic copper-clad substrate is cooled to room temperature, wire For the cutting process, use a metal tungsten wire parallel to the upper surface of the uppermost ceramic tile (101), and align it with the center of the through hole for longitudinal cutting until it reaches the strip groove (104) of the next layer of copper tile (103). ) position, end the cutting, and obtain the ceramic dam copper-clad substrate; Step S5: Use cleaning fluid to perform surface treatment on the ceramic dam copper-clad substrate. Attach silver solder tabs to both ends of the surface-treated ceramic dam copper-clad substrate strip groove (104), and then attach the chip. (303), ensure that the directions of the positive and negative electrodes of the chip at each dam position are consistent, then hot-press and sinter at 200-250°C for 5-30 minutes, pour epoxy resin into the through-hole position for curing, and finally add the bottom copper sheet ( Weld the positive (301) wire and the negative (303) wire to both ends of 103), connect the power supply, and the LED chip emits light. 2. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: in step S1, the ceramic piece is one of Al ₂ O ₃ , AlN, and Si ₃ N ₄ The thickness is 0.15~1mm, and the copper sheet is surface-treated metal copper without oxide layer, and the thickness is 0.1~0.4mm. 3. The preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that the thickness of the solder layer in step S2 is 5-15 μm. 4. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: the process conditions of copper etching in step S3 are: copper ion mass concentration is 2-3g/L , the copper complexing agent uses iminodiacetic acid with a mass fraction of 1.5-2.0%, a hydrogen peroxide mass fraction of 15-20%, a temperature of 30-45°C, and a time of 5-25 minutes. 5. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: the etching liquid for solder etching in step S3 includes: 300-500g/L ferric chloride, 2 -3g/L hydrochloric acid, 10-30g/L sodium hypochlorite, 0.05-0.10g/L phenyltriazole, temperature 30-45℃, time 10-25min. 6. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: in step S3, the width of the strip groove is 0.1 to 1 mm, and the width of the adjacent strip grooves is 0.1 to 1 mm. The spacing is consistent with the center spacing of the through holes cut by the uppermost ceramic tile. 7. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: the solvent used in the surface degreasing process in step S4 is ethanol, isopropyl alcohol, or acetone. A sort of. 8. Preparation of a high-power LED packaging structure based on ceramic dam according to claim 1, characterized in that: the curing process conditions in step S5 are: curing temperature 80-150°C, curing time 5-60 minutes . 9. A high-power LED packaging structure based on ceramic dam prepared according to any one of claims 1-8. 10. An LED light-emitting device prepared according to the high-power LED packaging structure of claim 9.