Manufacturing process of LED thermoelectric separation aluminum substrate

Abstract

The invention discloses a manufacturing process of an LED thermoelectric separation aluminum substrate, and relates to the technical field of LED thermoelectric separation aluminum substrates for new energy automobiles, and the manufacturing process of the LED thermoelectric separation aluminum substrate comprises the following steps: S1, cutting; s2, a copper-aluminum composite board is manufactured firstly, a dry film is attached to the copper-aluminum composite board, etching is conducted, and a local boss is formed; s3, making a GTL layer circuit on the FR-4 substrate, and pasting a dry film negative film for etching; s4, pasting pure glue on the FR-4 substrate after the FR-4 substrate is subjected to over-browning, and compacting the FR-4 substrate by a film pressing machine; s5, drilling corresponding target holes according to the target designed by the FR-4 substrate; s6, performing windowing treatment on a boss region corresponding to the FR-4 substrate; s7, typesetting and pressing the FR-4 substrate, the copper-aluminum composite board and the buffer layer to form a board; s8, drilling is carried out on the laminated plate piece; s9, performing outer layer resistance welding and surface treatment; s10, electrical testing and forming are carried out; according to the LED thermoelectric separation aluminum substrate manufactured through the manufacturing process of the LED thermoelectric separation aluminum substrate, the heat dissipation capacity of an LED is greatly improved, and the illumination time and the service life of the LED are directly prolonged.

Description

Technical Field

[0001] The present invention relates to the field of LED thermoelectric separation aluminum substrate technology for new energy vehicles, and in particular to a manufacturing process of an LED thermoelectric separation aluminum substrate. Background Art

[0002] New energy vehicles or high-power charging piles all need light-emitting diodes. As a new generation of solid-state light sources, light-emitting diodes (LEDs) have many advantages such as long life, high efficiency and energy saving, and green environmental protection. They are widely used in the field of display lighting. With the development of science and technology, advanced technologies are constantly applied to semiconductor production to continuously improve the luminous efficiency of LEDs and continuously reduce costs. The core part of LED is the PN junction. When the injected electrons and holes recombine at the PN junction, the electrical energy is directly converted into light energy. However, not all the converted light energy is enough to be emitted outside the LED. It will be converted into heat energy by the absorber inside the PN junction and epoxy resin / silicone. Figure 1 As shown in the figure, this heat energy has a huge side effect on the lamp. If the heat cannot be effectively dissipated, the internal temperature of the LED will rise. The higher the temperature, the lower the luminous efficiency of the LED and the shorter the life of the LED. In severe cases, the LED chip will fail immediately. Therefore, heat dissipation is still a huge obstacle to the application of high-power LEDs.

[0003] Existing heat dissipation technology: The heat generated by the PN junction of the LED passes through the LED base, solder paste welding layer, copper coating layer, insulation layer, aluminum plate, thermal conductive silicone gasket / silicone grease, heat dissipation aluminum profile, and then dissipates into the air, thus completing the heat dissipation process. Figure 2 As shown in the figure; the thermal conductivity of the LED base is about 80W / mk; the thermal conductivity of the solder paste welding layer is greater than 60W / mk; the thermal conductivity of the copper layer is about 400W / mk, the thermal conductivity of the aluminum plate and aluminum profile is about 200W / mk, the thermal conductivity of the insulation layer is about lw / mk, and the thermal conductive silicone gasket / silicone grease is about SW / mk. However, the closer to the PN junction of the LED, the higher the heat flux density, and the thermal conductive silicone sheet / silicone grease has the aluminum plate lateral heat conduction to even out the temperature, so the heat flux density of the insulation layer is much higher than that of the thermal conductive silicone gasket / silicone grease. Therefore, in summary, it can be clearly seen that the heat dissipation bottleneck lies in the insulation layer of the aluminum substrate; in view of this situation, it is urgent to develop a manufacturing process for LED thermoelectric separation aluminum substrate to meet the needs of actual use. Summary of the invention

[0004] In view of this, the present invention aims to address the deficiencies in the prior art, and its main purpose is to provide a process for manufacturing an LED thermoelectric separation aluminum substrate. The LED thermoelectric separation aluminum substrate manufactured by adopting the process for manufacturing an LED thermoelectric separation aluminum substrate provided by the present application greatly enhances the heat dissipation capacity of the LED, directly extending the lighting time and service life of the LED; the process for manufacturing an LED thermoelectric separation aluminum substrate provided by the present application solves the current technical bottleneck and is suitable for the manufacture of a new type of automotive LED thermoelectric separation aluminum substrate.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A process for manufacturing an LED thermal and electrical separation aluminum substrate comprises the following steps:

[0007] S1. Cut the FR-4 substrate, copper-aluminum composite board and pure glue respectively;

[0008] S2, first make a copper-aluminum composite plate, apply dry film etching, and form a local boss;

[0009] S3 and FR-4 substrates are used to make GTL layer circuits, and dry film negative etching is applied;

[0010] S4, FR-4 substrates are browned and then coated with pure glue and compacted by laminator: copper-aluminum composite plates are browned with browning liquid after the bosses are etched;

[0011] S5. Drill corresponding target holes according to the target designed for the FR-4 substrate;

[0012] S6. Window processing is performed on the FR-4 substrate corresponding to the boss area, and the compensation value of the window area is reasonably compensated: take pure glue to fit the FR-4 substrate and make a groove, then add the FR-4 bare board to overlap and press, slice and measure the distance of the overflow glue, determine the actual overflow glue amount and engineering compensation coefficient, the compensation data of the pure glue groove is 0.1-0.2mm larger than the single side of the boss;

[0013] S7. Lay out and press the FR-4 substrate, copper-aluminum composite board and buffer layer to form a board: the initial temperature of pure glue pressing is 110-130℃, and press the combined board to be pressed;

[0014] S8, drilling holes in the pressed panels;

[0015] S9, do outer layer solder mask and surface treatment;

[0016] S10, electrical testing and forming.

[0017] As a preferred solution: in step S7, a press is used for pressing, and the pressure applied by the press is controlled to be 30-40 kgf / cm 2The pressing temperature of pure glue is 110-160℃, the heating rate is controlled within 2-3℃ / min, and the temperature and pressure time is maintained for more than 90min.

[0018] As a preferred solution: the buffer layer in step S7 includes an upper release film located at the upper layer, a silicone sheet located at the middle layer, and a lower release film located at the lower layer.

[0019] As a preferred solution: in step S4, the browning is to use H2O2 and H2SO4 to micro-etch the copper surface of the copper-aluminum composite plate, and the organic additives in the browning solution react with the copper surface to form a layer of organic metal conversion film, which is embedded in the copper surface to form a grid-like conversion layer between the copper surface and the resin.

[0020] As a preferred solution: in step S2, the copper-aluminum composite plate is a copper-aluminum composite plate containing 15% copper, and a 155-165 μm copper layer is etched to make a boss, and the copper layer of the copper-aluminum composite plate is etched step by step with the copper layer facing downward.

[0021] As a preferred solution: the specific steps of etching the copper-aluminum composite plate with the copper layer facing downward in step S2 are: first, etching at a line speed of 3.0 m / min to etch copper with a thickness of 90 μm; second, etching at a line speed of 2.4 m / min to etch 60 μm.

[0022] As a preferred solution: the LED thermal-electric separation aluminum substrate includes L1 layer, L2 layer, L3 layer and L4 layer distributed in layers from top to bottom, the L1 layer and L2 layer are FR-4 substrates, the L3 layer and L4 layer form a copper-aluminum composite plate, the L3 layer is a copper layer, the L4 layer is an aluminum layer, and the boss is located in the middle of the L3 layer.

[0023] As a preferred solution: the specific steps of arranging and pressing the FR-4 substrate, the copper-aluminum composite board and the buffer layer to form a board in step S7 are as follows: first, the copper-aluminum composite board is browned, and after cooling, the aluminum layer protective film needs to be torn off, and the release film of the pure adhesive surface is torn off, and combined with the L3 layer of the copper-aluminum composite board, the board is glued to fix the four corners, and the buffer layer is used instead of the copper foil, and the board is double-assembled.

[0024] As a preferred solution, the step S4 of pasting pure glue specifically includes: first tearing off the pure glue release paper, and then pasting it with the bottom surface of the FR-4 substrate in a neat direction, and passing it through a thermoforming machine once, and the thermoforming machine needs to be heated to 110°C.

[0025] As a preferred solution: in step S6, the gong groove is a gong-out boss fitting groove, and a double-edged milling cutter is used when gong-outing the groove to reduce burr residue.

[0026] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical scheme that the problem of bubbles in the non-flowing pure glue pressing plate is solved by adopting the manufacturing process of the LED thermoelectric separation aluminum substrate provided by the present application, and the depression around the convex copper (boss position) is controlled to ensure the bonding strength between the pure glue and the FR-4 substrate and the copper layer; the manufactured LED thermoelectric separation aluminum substrate greatly enhances the heat dissipation capacity of the LED, directly prolongs the lighting time and service life of the LED; the Lianzhi pure glue pressing technology, metal substrate etching convex copper technology, pure glue CNC cutting technology, covering film protection technology, dynamic area window opening technology, metal base molding technology, etc. are adopted to solve the current technical bottleneck, which is suitable for the manufacture of new automotive LED thermoelectric separation aluminum substrates.

[0027] In order to more clearly illustrate the structural features and effects of the present invention, it is described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram of the LED light-heat energy conversion mechanism of the present invention;

[0029] Figure 2 It is a schematic diagram of the LED heat dissipation model of the present invention;

[0030] Figure 3 This is a schematic diagram of the heat conduction effect of LEDs of the present invention;

[0031] Figure 4 A schematic diagram of pressure application during the pressing process of the present invention;

[0032] Figure 5 It is a schematic diagram of the structure of the buffer layer material of the present invention;

[0033] Figure 6 It is a pure adhesive lamination parameter curve diagram of the present invention;

[0034] Figure 7 It is a schematic diagram of the gong slot control of the present invention;

[0035] Figure 8 It is a schematic diagram of the copper layer browning of the present invention;

[0036] Fig. 9 This is a schematic diagram of the structure of the LED thermal and electrical separation aluminum substrate of the present invention;

[0037] Fig.10 This is a process flow chart of manufacturing the LED thermal and electrical separation aluminum substrate in Example 1 of the present invention;

[0038] Fig.11 This is a first-view test effect diagram of the LED thermal and electrical separation aluminum substrate of the present invention;

[0039] Fig.12 This is a test result diagram of the LED thermal and electrical separation aluminum substrate of the present invention showing the overflow of adhesive from the second viewing angle. DETAILED DESCRIPTION

[0040] The present invention Figures 1 to 12 As shown, a process for manufacturing an LED thermal and electrical separation aluminum substrate includes the following steps:

[0041] S1. Cut the FR-4 substrate, copper-aluminum composite board and pure glue respectively;

[0042] S2, first make a copper-aluminum composite plate, apply dry film etching, and form a local boss;

[0043] S3 and FR-4 substrates are used to make GTL layer circuits, and dry film negative etching is applied;

[0044] S4, FR-4 substrates are browned and then coated with pure glue and compacted by laminator: copper-aluminum composite plates are browned with browning liquid after the bosses are etched;

[0045] S5. Drill corresponding target holes according to the target designed for the FR-4 substrate;

[0046] S6. Window processing is performed on the FR-4 substrate corresponding to the boss area, and the compensation value of the window area is reasonably compensated: take pure glue to fit the FR-4 substrate and make a groove, then add the FR-4 bare board to overlap and press, slice and measure the distance of the overflow glue, determine the actual overflow glue amount and engineering compensation coefficient, the compensation data of the pure glue groove is 0.1-0.2mm larger than the single side of the boss;

[0047] S7. Lay out and press the FR-4 substrate, copper-aluminum composite board and buffer layer to form a board: the initial temperature of pure glue pressing is 110-130℃, and press the combined board to be pressed;

[0048] S8, drilling holes in the pressed panels;

[0049] S9, do outer layer solder mask and surface treatment;

[0050] S10, electrical testing and forming.

[0051] In step S7, a press is used for pressing, and the pressure applied by the press is controlled to be 30-40 kgf / cm 2 The pressing temperature of pure glue is 110-160℃, the heating rate is controlled within 2-3℃ / min, and the temperature and pressure time is maintained for more than 90min.

[0052] The buffer layer in step S7 includes an upper release film located at the upper layer, a silicone sheet located at the middle layer, and a lower release film located at the lower layer.

[0053] In step S4, the browning process is to micro-etch the copper surface of the copper-aluminum composite plate using H2O2 and H2SO4, and the organic additives in the browning solution react with the copper surface to form an organic metal conversion film, which is embedded in the copper surface to form a grid-like conversion layer between the copper surface and the resin.

[0054] In step S2, the copper-aluminum composite plate is a copper-aluminum composite plate containing 15% copper, and a copper layer of 155-165 μm is etched to make a boss, and the copper layer of the copper-aluminum composite plate is etched step by step with the copper layer facing downward.

[0055] The specific steps of etching the copper-aluminum composite plate with the copper layer facing downward in step S2 are: first, etching at a line speed of 3.0 m / min to etch a copper thickness of 90 μm; second, etching at a line speed of 2.4 m / min to etch 60 μm.

[0056] The LED thermal-electric separation aluminum substrate comprises an L1 layer, an L2 layer, an L3 layer and an L4 layer which are distributed in layers from top to bottom. The L1 layer and the L2 layer are FR-4 substrates. The L3 layer and the L4 layer form a copper-aluminum composite plate. The L3 layer is a copper layer, the L4 layer is an aluminum layer, and the boss is located in the middle of the L3 layer.

[0057] In step S7, the specific steps of arranging and pressing the FR-4 substrate, the copper-aluminum composite board and the buffer layer to form a board are as follows: first, the copper-aluminum composite board is browned, and after cooling, the aluminum layer protective film needs to be torn off, and the release film of the pure adhesive surface is torn off, and combined with the L3 layer of the copper-aluminum composite board, the board is glued to fix the four corners, and the buffer layer is used instead of the copper foil to double-assemble the board.

[0058] The specific steps of pasting the pure glue in step S4 are as follows: firstly, the pure glue release paper is torn off, and then the pure glue is pasted on the bottom surface of the FR-4 substrate in a straight direction, and then the two are passed through a thermoforming machine once, and the thermoforming machine needs to be heated to 110°C.

[0059] In step S6, the grooving groove is a groove for the grooving boss to fit in, and a double-edged milling cutter is used when grooving the groove to reduce burr residue.

[0060] Example 1: A manufacturing process for LED thermal and electrical separation aluminum substrate

[0061] 1. Cutting of FR-4 substrate and copper-aluminum composite board

[0062] Use a CNC cutting machine to cut to the corresponding size. The bottom aluminum layer of the copper-aluminum composite plate is covered with a protective film. Be careful not to scratch or dent it during the cutting and handling process. A damaged protective film will not provide protection, and post-process etching may cause dents in the aluminum layer.

[0063] 2. Drilling of FR-4 substrate and copper-aluminum composite board

[0064] This drilling only drills the LDI positioning holes at the four corners of the board. The copper-aluminum composite board is drilled with the copper layer facing up. After drilling, the FR-4 layer is polished normally to remove the burrs. The copper-aluminum composite board has a PVC protective film on its copper layer, which needs to be removed before polishing, leaving only the protective film of the aluminum layer.

[0065] 3. Fabrication of L1 and L2 layers of FR-4 substrate

[0066] The thickness of the FR-4 substrate is 0.25mm. During the pre-processing of optical imaging, red tape should be attached to the edge of the optical board and the board strips should be carried through the pre-processing. When pressing the dry film, the board should be held with both hands and finger cots should be worn to prevent the board surface from wrinkling and oxidation. Turn on the pressure switch and adjust it to 6kg / cm 2 ; Use a new knife to cut the film to prevent the dry film from breaking into pieces and falling onto the board, causing poor exposure and short circuits. Be careful not to cut the soft board with enough force. When exposing the negative film, clean the exposure table and glass Mylar to prevent short circuits.

[0067] 4. Etch the L1 layer circuit and etch the L2 layer bare board

[0068] 5. L3-L4 boss exposure

[0069] It is made of 15% copper-aluminum composite board with a thickness of 1.6mm, of which the copper thickness is 225μm. The copper layer of 155-165μm needs to be etched to make the boss. When pre-treating the outer layer, the lower grinding brush needs to be turned off, the board is ground on one side, and the dry film is attached to both sides of the copper-aluminum board. The negative film is exposed. In this step, the copper layer boss pattern is made, and the aluminum layer is exposed on the entire surface to protect the aluminum layer from being attacked by the liquid.

[0070] 6. Boss Etching

[0071] Acid etching: This step requires etching 155-165μm on the 225μm base copper, and the copper layer is etched step by step with the copper layer facing down. In the first step, the etching line speed is 3.0m / min and the copper thickness is 90μm; in the second step, the etching line speed is 2.4m / min and the etching is 60μm. The first piece to be etched needs to be sliced ​​with a metallographic microscope to measure the height of the boss and the width of the boss beach, and qualified batch production.

[0072] 7. L2 layer with pure glue

[0073] Before operation, check whether the L2 layer is etched clean. Ensure that there is no residual copper or dirt on the entire surface. Sandblasting can be used to clean it once. Pure glue needs to be refrigerated and left to thaw for 2 hours after leaving the warehouse. First tear off the pure glue release paper, and then fit it with the bottom surface of the FR-4 substrate. The direction must be neat and pass through the thermoforming machine together. The thermoforming machine needs to be heated to 110°C. After being heated, the pure glue can produce a certain degree of viscosity to facilitate the initial combination with the substrate. Further cut the excess pure glue on the edge of the board and roll it through the manual laminating machine for further compaction.

[0074] 8. FR-4 substrate layer with rubber groove

[0075] After the pure glue is attached to the substrate, it is necessary to drill positioning holes on the edge of the board. The holes must match the L1 layer circuit pattern. Use a CCD punching machine with the pure glue facing up to drill holes. After completion, further grooving is done to grooving out the boss matching groove. When grooving, a double-edged milling cutter can be used to reduce burr residues, and the upper and lower clamping boards are compacted.

[0076] 9. Pressing

[0077] First, brown the copper-aluminum composite board, and after cooling, tear off the aluminum protective film (this film is not resistant to high temperatures). Tear off the release film on the pure adhesive surface, and combine it with the L3 layer of the copper-aluminum composite board. Use a ten-fold microscope to observe the matching of the boss and the groove, and then use high-temperature tape to stick the four corners of the board to fix it. Use a three-in-one silicone pad (buffer layer) instead of copper foil, double-ply the board, and the pressing pressure needs to be 50% greater than the normal FR-4 substrate pressure. After pressing, use an X-RAY target drilling machine to drill the target hole.

[0078] 10. Grinding rubber + drilling peripheral holes

[0079] Use a three-in-one silicone pad, with little pure glue overflow, and it can be passed through a copper plating rough grinder normally; drill holes around the board and locate the target holes.

[0080] 11. Solder mask, text

[0081] To make solder mask and text normally, it is necessary to pay attention to the aluminum layer of the aluminum composite plate needs to be protected by blue tape before the solder mask is polished. The lower grinding brush needs to be turned off before the solder mask is processed, and the protective tape should be torn off after the text is baked.

[0082] 12. Immersion Gold

[0083] The whole surface of the aluminum layer is covered with film and compacted without any gaps to ensure that the aluminum layer is not damaged during the micro-etching cylinder section and only the top layer is etched with gold.

[0084] 13. Secondary drilling

[0085] Normal drilling operation requires the use of high-density pads and aluminum sheets. A drilling rig with a speed of more than 160,000 revolutions must be used. The number of stacked plates: a maximum of 2 plates / stack. The gold surface cannot be polished after drilling.

[0086] 14. Forming and grinding aluminum layer

[0087] V-CUT requires the use of a diamond knife, the tool speed is reduced by 30%, the travel speed is reduced by 50%, and burrs remain on the board surface after V-cutting. The gold surface is formed by pasting blue tape, and the aluminum layer faces downward during gong. After forming, the copper plate is sent to the copper plate grinding machine to grind the aluminum layer with a single-sided brush. This step can remove burrs and oxides on the aluminum layer.

[0088] 15. Electrical test: Test according to routine requirements

[0089] After production, thermal stress test of LED thermal and electrical separation aluminum substrate is carried out

[0090] The pressed panels were sampled for thermal shock testing at 288°C for 10 seconds for 8 times to check for blistering and delamination. The results showed that there was no blistering or delamination on both sides of the produced LED thermoelectric separation aluminum substrate.

[0091] Solderability test

[0092] Place the sample in an oven at 105±5℃ and bake for 1-2 hours to dry the moisture and other volatiles on the board surface. After baking, cool to room temperature and immerse the sample completely in rosin for 5-10 seconds. Take out the sample, place it vertically for 1 minute and absorb the rosin on the surface of the sample. Clamp the sample flat and let the sample float on the tin surface for 3-5 seconds.

[0093] After the test time is reached, the sample is carefully removed from the soldering surface and kept horizontal until it solidifies, and the tinning effect is observed; the results show that the tinning effect on the gold surface is good and there is no tin sticking to the aluminum layer.

[0094] Glue overflow test: The result shows that the glue overflow is in good condition. Fig.11 and Fig.12 shown.

[0095] Since the bottleneck of heat dissipation is the insulating layer on the aluminum substrate, for automotive LED lights, a new processing technology of thermoelectric separation can be used to process the aluminum substrate, which greatly enhances the heat dissipation capacity of the LED lamps. Under the original LED base of the aluminum substrate, the copper cladding and the insulating layer are removed to expose the thermally conductive aluminum plate. However, aluminum cannot be directly soldered, so a metal layer that can be soldered needs to be plated on the exposed aluminum plate. After the aluminum substrate processing technology is completed, the heat generated by the PN junction of the LED passes through the LED base → solder paste welding block → aluminum plate → thermal conductive silicone gasket → heat dissipation aluminum profile → dissipated into the air. After the new lamp structure removes the insulating layer with a very small thermal conductivity coefficient, the LED heat dissipation capacity is greatly enhanced, which directly extends the LED lighting time and service life. See Figure 3 As shown; this application adopts Lianzhi pure glue pressing technology, metal substrate etching convex copper technology, pure glue CNC cutting technology, covering film protection technology, dynamic area window opening technology, metal base molding technology, etc., which solves the current technical bottleneck and is suitable for the production of new automotive LED thermoelectric separation aluminum substrates.

[0096] The key technical issues solved by this application are:

[0097] The new LED thermal and electrical separation aluminum substrate is made of copper-aluminum composite material, with local etching of bosses and pure glue pressing. The key technical issues involved are as follows:

[0098] 1. Bubble problem in non-flowing pure glue plywood

[0099] Since the colloid fluidity of non-flowing pure glue is poor, uniform pressure buffering is required during the pressing process to achieve the effect of colloid exhaust, so bubbles are prone to appear during the pressing process; from the perspective of the mechanism of non-flowing pure glue itself, the colloid itself does not have fluidity, and the filling area is mainly press negative pressure in a vacuum environment and high pressure contact to make it completely fit. Therefore, try to use materials with excellent buffering performance as the buffer layer to increase the pressure on the filling area; such as Figure 4 shown.

[0100] Solution:

[0101] Excellent cushioning materials can enhance the pressure of the glue filling area, so that the area can be filled fully after being compressed. Avoid the phenomenon of lack of glue. The cushioning layer uses three-in-one material, which is divided into three layers, such as Figure 5 As shown; the upper and lower layers are high-temperature release films, and the middle layer is a silicone sheet, which has excellent pressure-relieving ability and high heat resistance. It is not easy to deform after high pressure, and the heat transfer performance is also very excellent.

[0102] The initial temperature of pure glue pressing is between 110-130℃. Place the bonding board to be pressed, and control the pressure of the press to 30-40kgf / cm 2 Conventional flow epoxy materials require a temperature range of 80-140°C, with a heating rate of 1.5-2.5°C / min, while Lianzhi pure glue materials require a temperature range of 110-160°C, with a heating rate of 2-3°C / min, and the temperature and pressure time should be maintained for more than 90 minutes; Figure 6 shown.

[0103] 2. Control of depression around convex copper: Use pure glue for lamination. The material properties determine the width of the overflow glue at the edge of the board. This project uses Lianzhi pure glue material, and the lamination overflow glue is ≤0.2mm. If the window opening of the FR-4 substrate material and the specifications of the composite layer convex copper block cannot be matched accordingly, there will be problems with gap interference or boss coverage.

[0104] Solution:

[0105] Before the test, take the pure glue to stick the FR-4 substrate copper clad board and make a 2*3mm square groove, then add the FR-4 substrate to overlap and press it. After completion, send it to the laboratory for slicing and measuring the distance of the overflow glue. Figure 7 As shown: The actual amount of glue overflow and the engineering compensation coefficient were determined through experiments, thus solving the problem of pure glue sinking and glue overflow at the junction of the convex copper and the window of the FR-4 substrate; finally, it was determined that the compensation data of the pure glue gong groove was 0.15mm larger than the single side of the convex copper.

[0106] 3. The bonding strength between pure glue and FR-4 substrate and copper layer

[0107] Lianzhi pure glue has poor bonding strength with FR-4 substrate, which can easily cause board explosion and interlayer voids. The main reason is that the bottom layer of the FR-4 substrate needs to be etched into a bare board, the thickness of the board is 0.25mm, and the top layer has a circuit pattern. When pressed, the pressed area of ​​the substrate is uneven, and the local copper-free area is pressure-free and easily forms voids. Pure glue material is highly inert, and even at high temperatures, the adhesive in the pure glue still cannot produce sufficient fluidity and cannot fully fill the gap, so making the pure glue and the substrate fully bonded is the key to solving interlayer voids.

[0108] Solution:

[0109] After the copper-aluminum composite plate is etched, it is browned. Browning is the micro-etching of the copper surface using H2O2 and H2SO4. The organic additives in the browning solution react with the copper surface to form an organic metal conversion film. This film can effectively embed into the copper surface and form a grid-like conversion layer between the copper surface and the resin. Figure 8 shown.

[0110] Reaction equation:

[0111] Cu+H2SO4+H2O2→CuSO4+2H2O

[0112] Cu+nA→Cu(A)n→Brown Coating

[0113] LED thermal and electrical separation aluminum substrate Fig. 9 As shown, the LED thermal-electric separation aluminum substrate includes L1 layer, L2 layer, L3 layer and L4 layer distributed in layers from top to bottom, the L1 layer and L2 layer are FR-4 substrates, the L3 layer and L4 layer form a copper-aluminum composite plate, the L3 layer is a copper layer, the L4 layer is an aluminum layer, and the boss is located in the middle of the L3 layer.

[0114] Among them, L3 is a copper layer with etched bosses, and L4 is a smooth aluminum layer with no vias in the board. The bosses fit in with the grooves of the FR-4 substrate.

[0115] The design focus of the present invention is to solve the problem of bubbles in the non-flowing pure glue pressing plate by adopting the manufacturing process of the LED thermoelectric separation aluminum substrate provided by the present application, realize the control of the depression around the convex copper, and ensure the bonding force between the pure glue and the FR-4 substrate and the copper layer; the LED thermoelectric separation aluminum substrate produced by the manufacturing method greatly enhances the heat dissipation capacity of the LED, directly prolongs the lighting time and service life of the LED; the Lianzhi pure glue pressing technology, metal substrate etching convex copper technology, pure glue CNC cutting technology, covering film protection technology, dynamic area window opening technology, metal base molding technology, etc. are adopted to solve the current technical bottleneck, which is suitable for the manufacture of new automotive LED thermoelectric separation aluminum substrates.

[0116] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for manufacturing an LED thermal and electrical separation aluminum substrate, characterized in that: The steps include: S1. Cut the FR-4 substrate, copper-aluminum composite board and pure glue respectively; S2, first make a copper-aluminum composite plate, apply dry film etching, and form a local boss; S3 and FR-4 substrates are used to make GTL layer circuits, and dry film negative etching is applied; S4, FR-4 substrates are browned and then coated with pure glue and compacted by laminator: copper-aluminum composite plates are browned with browning liquid after the bosses are etched; S5. Drill corresponding target holes according to the target designed for the FR-4 substrate; S6. Window processing is performed on the FR-4 substrate corresponding to the boss area, and the compensation value of the window area is reasonably compensated: take pure glue to fit the FR-4 substrate and make a groove, then add the FR-4 bare board to overlap and press, slice and measure the distance of the overflow glue, determine the actual overflow glue amount and engineering compensation coefficient, the compensation data of the pure glue groove is 0.1-0.2mm larger than the single side of the boss; S7. Lay out and press the FR-4 substrate, copper-aluminum composite board and buffer layer to form a board: the initial temperature of pure glue pressing is 110-130℃, and press the combined board to be pressed; S8, drilling holes in the pressed panels; S9, do outer layer solder mask and surface treatment; S10, electrical testing and forming.

2. The manufacturing process of the LED thermal and electrical separation aluminum substrate according to claim 1 is characterized in that: In step S7, a press is used for pressing, and the pressure applied by the press is controlled to be 30-40 kgf / cm 2 The pressing temperature of pure glue is 110-160℃, the heating rate is controlled within 2-3℃ / min, and the temperature and pressure time is maintained for more than 90min.

3. The manufacturing process of the LED thermal and electrical separation aluminum substrate according to claim 1 is characterized in that: The buffer layer in step S7 includes an upper release film located at the upper layer, a silicone sheet located at the middle layer, and a lower release film located at the lower layer.

4. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 1, characterized in that: In step S4, the browning is to use H2O2 and H2SO4 to micro-etch the copper surface of the copper-aluminum composite plate, and the organic additives in the browning solution react with the copper surface to form a layer of organic metal conversion film, which is embedded in the copper surface to form a grid-like conversion layer between the copper surface and the resin.

5. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 1, characterized in that: In step S2, the copper-aluminum composite plate is a copper-aluminum composite plate containing 15% copper, and a copper layer of 155-165 μm is etched to make a boss, and the copper layer of the copper-aluminum composite plate is etched step by step with the copper layer facing downward.

6. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 5, characterized in that: The specific steps of etching the copper-aluminum composite plate in step S2 with the copper layer facing downward are as follows: first, etching at a line speed of 3.0 m / min to etch copper with a thickness of 90 μm; Second: Etching line speed 2.4m / min etching 60μm.

7. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 1, characterized in that: The LED thermal-electric separation aluminum substrate includes L1 layer, L2 layer, L3 layer and L4 layer distributed in layers from top to bottom, the L1 layer and L2 layer are FR-4 substrates, the L3 layer and L4 layer form a copper-aluminum composite plate, the L3 layer is a copper layer, the L4 layer is an aluminum layer, and the boss is located in the middle of the L3 layer.

8. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 7, characterized in that: In step S7, the specific steps of arranging and pressing the FR-4 substrate, the copper-aluminum composite board and the buffer layer to form a board are as follows: first, the copper-aluminum composite board is browned, and after cooling, the aluminum layer protective film needs to be torn off, and the release film of the pure adhesive surface is torn off, and combined with the L3 layer of the copper-aluminum composite board, the board is glued to fix the four corners, and the buffer layer is used instead of the copper foil to double-assemble the board.

9. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 1, characterized in that: The specific steps of pasting the pure glue in step S4 are as follows: firstly, the pure glue release paper is torn off, and then the pure glue is pasted on the bottom surface of the FR-4 substrate in a straight direction, and then the two are passed through a thermoforming machine once, and the thermoforming machine needs to be heated to 110°C.

10. The process for manufacturing the LED thermal and electrical separation aluminum substrate according to claim 1, characterized in that: In step S6, the grooving groove is a groove for the grooving boss to fit in, and a double-edged milling cutter is used to reduce burr residue when grooving.

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