A fabrication process for a single-sided, densely packed, high thermal conductivity copper substrate

Abstract

This invention discloses a manufacturing process for a single-sided, densely packed, high thermal conductivity copper substrate, relating to the field of circuit board processing technology. The manufacturing process includes the following steps: S1, copper substrate cutting; S2, flatness inspection; S3, copper substrate browning; S4, high-conductivity adhesive lamination; and S5, subsequent processing. This manufacturing process for a single-sided, densely packed, high thermal conductivity copper substrate involves two flatness inspections. The first inspection checks the overall flatness, and the second checks for any concave surfaces invisible to the naked eye. If the inspections pass, and the board surface and the high-conductivity adhesive bonding surface are clean and free of debris, the copper substrate is bonded and laminated with the high-conductivity adhesive. This avoids damage to the dielectric layer caused by small particles or uneven surfaces during processing. Furthermore, the copper substrate is wrapped in paper or coated with adhesive for protection throughout the process of handling between processes to prevent the adsorption of external small particles, thereby ensuring the quality of the final product.

Description

Technical Field

[0001] This invention relates to the field of circuit board processing technology, specifically to a manufacturing process for a single-sided, densely packed, high thermal conductivity copper substrate. Background Technology

[0002] As the name suggests, a single-sided dense circuit high thermal conductivity copper substrate has its conductors concentrated on one side of the high thermal conductivity copper substrate. The thermal conductivity of copper substrates is much better than that of aluminum substrates and laminate substrates, hence the name high thermal conductivity copper substrate. High thermal conductivity copper substrates mainly solve the thermal resistance of the product's light-emitting element through an ultra-thin dielectric layer, which quickly conducts the heat generated by the light-emitting element. The thickness of the dielectric layer is generally within 100 micrometers, and the thinner the dielectric layer, the more stringent the manufacturing requirements become during the product processing.

[0003] Existing single-sided, densely packed, high thermal conductivity copper substrates are susceptible to damage during manufacturing due to the thin dielectric layer. This can be caused by small particles or other impurities that can lead to breakage of the dielectric layer after lamination. This can result in defects such as short circuits between the conductive lines and the substrate in subsequent processes, ultimately leading to product scrap. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a fabrication process for a single-sided, densely packed, high thermal conductivity copper substrate, thus solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing process for a single-sided, densely packed, high thermal conductivity copper substrate, the manufacturing process comprising the following steps:

[0006] S1. Copper substrate blanking:

[0007] Cut out the copper substrate of the required size using a cutting device, and then use a grinding device to grind one side of the copper substrate to eliminate uneven areas. After grinding, observe whether the ground surface is clean, whether there are any bumps or small particles of debris.

[0008] S2. Flatness inspection:

[0009] Place the polished surface of the copper substrate on a flat table, hold down one corner of the copper substrate, and use a measuring device to obtain the height of the raised corner. If the raised height is greater than 0.75% of the total length of the diagonal of the copper substrate, it means that the flatness is not enough and it needs to be polished again. If the raised height is less than 0.75% of the total length of the diagonal of the copper substrate, it means that the polishing is qualified.

[0010] S3, Copper substrate browning:

[0011] The copper substrate surface is roughened by using a browning solution to increase the bonding area.

[0012] S4, High Adhesive Conductivity Pressing:

[0013] The polished surface of the copper substrate is brought into contact with the adhesive surface of the high-conductivity adhesive, so that the copper substrate and the high-conductivity adhesive are stacked, and then pressed together to firmly bond the high-conductivity adhesive and the copper substrate together.

[0014] S5. Subsequent Production:

[0015] After the high-conductivity adhesive is laminated to the copper substrate, it goes through a pattern transfer process, an etching inspection process, a solder mask process, and finally passes the final inspection to obtain the finished product.

[0016] Furthermore, in step S1, when grinding the copper substrate, it is first secured and the surface to be ground is exposed. Several balls are embedded in the copper substrate in a ring shape around its perimeter. The top surface of the balls is the same thickness as the copper substrate after grinding. Then, the grinding disc is attached to the surface of the copper substrate for grinding until the grinding disc contacts the balls. At this time, the balls rotate in place due to friction, which does not delay the grinding operation of the grinding disc and also prevents the grinding disc from over-grinding and causing the copper substrate to become thinner.

[0017] Furthermore, in step S2, if the raised height is less than 0.75% of the total diagonal length of the copper substrate, further flatness testing is required to prevent concavity in the polished surface.

[0018] Furthermore, the further flatness inspection includes the following steps:

[0019] The copper substrate is placed inside the housing with the polished surface facing upwards. The housing and the copper substrate fit together perfectly. A hydrophobic film is adsorbed onto the polished surface of the copper substrate using vacuum adsorption. A scraper is then inserted close to one side of the inner wall of the housing. The scraper surface is hydrophobic, and the bottom of the scraper is attached to the surface of the copper substrate, i.e., the surface of the hydrophobic film. Water is poured into one side of the scraper, and the scraper is moved. The scraper moves along the surface of the hydrophobic film. If water moves to the other side of the scraper during the movement, it indicates that the surface of the copper substrate has a concave area. If the water does not move to the other side of the scraper, it indicates that the surface of the copper substrate is flat.

[0020] Furthermore, in step S4, the high-conductivity adhesive is a high-thermal-conductivity adhesive.

[0021] Furthermore, in step S4, before the high-conductivity adhesive is bonded to the polished surface of the copper substrate, it must be confirmed that the bonding surface of the high-conductivity adhesive is clean, free of cracks, and free of small particles and debris.

[0022] Furthermore, in step S4, the highly conductive adhesive is the dielectric layer.

[0023] Furthermore, in step S4, the thickness of the highly conductive adhesive is 50 micrometers.

[0024] Furthermore, in steps S1-S5, the copper substrate needs to be wrapped in paper or coated with adhesive for protection throughout the process of turnover.

[0025] This invention provides a fabrication process for a single-sided, densely packed, high thermal conductivity copper substrate, which has the following advantages:

[0026] The manufacturing process of this single-sided, densely packed, high thermal conductivity copper substrate utilizes a 50-micron-thick high-conductivity dielectric layer to rapidly conduct heat generated by the product's light-emitting element. Two flatness tests are performed: the first checks overall flatness, and the second checks for any concave surfaces invisible to the naked eye. If these tests are passed, and the board surface and the high-conductivity adhesive bonding surface are ensured to be clean and free of debris, the copper substrate is bonded and pressed with the high-conductivity adhesive. This avoids damage to the dielectric layer caused by small particles or uneven surfaces during processing. Furthermore, the copper substrate is wrapped in paper or coated with adhesive throughout its transfer between processes to prevent the adsorption of external fine particles, thus ensuring the final product quality. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall process for manufacturing a single-sided, densely packed, high thermal conductivity copper substrate according to the present invention. Implementation

[0028] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0029] like Figure 1 As shown, the present invention provides a technical solution: a manufacturing process for a single-sided densely packed copper substrate with high thermal conductivity, the manufacturing process comprising the following steps:

[0030] S1. Copper substrate blanking:

[0031] Cut out the copper substrate of the required size using a cutting device, and then use a grinding device to grind one side of the copper substrate to eliminate uneven areas. After grinding, observe whether the ground surface is clean, whether there are any bumps or small particles of debris.

[0032] In the process of grinding the copper substrate, it is first secured and the surface to be ground is exposed. Several balls are embedded in the copper substrate in a ring shape around the perimeter. The top surface of the balls is the same thickness as the copper substrate after grinding. Then, the grinding disc is attached to the surface of the copper substrate for grinding until the grinding disc contacts the balls. At this time, the balls rotate in place due to friction, which does not delay the grinding operation of the grinding disc and also prevents the grinding disc from over-grinding and causing the copper substrate to become thinner.

[0033] S2. Flatness inspection:

[0034] Place the polished surface of the copper substrate on a flat table, hold down one corner of the copper substrate, and use a measuring device to obtain the height of the raised corner. If the raised height is greater than 0.75% of the total length of the diagonal of the copper substrate, it means that the flatness is not enough and it needs to be polished again. If the raised height is less than 0.75% of the total length of the diagonal of the copper substrate, it means that the polishing is qualified.

[0035] If the height of the raised section is less than 0.75% of the total diagonal length of the copper substrate, further flatness testing is required to prevent concavity in the polished surface.

[0036] Further flatness testing includes the following steps:

[0037] The copper substrate is placed inside the box with the polished surface facing up. The box and the copper substrate fit together perfectly. A hydrophobic film is adsorbed onto the polished surface of the copper substrate using vacuum adsorption. A scraper is then inserted close to one side of the inner wall of the box. The scraper surface is hydrophobic, and the bottom of the scraper is attached to the surface of the copper substrate, i.e. the surface of the hydrophobic film. Water is poured into one side of the scraper and the scraper is moved. The scraper moves along the surface of the hydrophobic film. If water moves to the other side of the scraper during the movement, it indicates that the surface of the copper substrate has a concave area. If the water does not move to the other side of the scraper, it indicates that the surface of the copper substrate is flat.

[0038] Two flatness tests were conducted. The first test checked the overall flatness, and the second test checked for any concave surfaces that were not visible to the naked eye. This was done to avoid damage to the medium layer caused by unevenness or concave surfaces that were not visible to the naked eye.

[0039] S3, Copper substrate browning:

[0040] The copper substrate surface is roughened by using a browning solution to increase the bonding area.

[0041] S4, High Adhesive Conductivity Pressing:

[0042] The polished surface of the copper substrate is brought into contact with the adhesive surface of the high-conductivity adhesive, so that the copper substrate and the high-conductivity adhesive are stacked, and then pressed together to firmly bond the high-conductivity adhesive and the copper substrate together.

[0043] Among them, the high thermal conductivity adhesive is a high thermal conductivity adhesive. Before bonding the high thermal conductivity adhesive to the polished surface of the copper substrate, it is necessary to confirm that the bonding surface of the high thermal conductivity adhesive is clean and free of cracks and small particles. The high thermal conductivity adhesive is the dielectric layer. The thickness of the high thermal conductivity adhesive is 50 micrometers. The heat generated by the light-emitting body of the product is quickly conducted through the 50-micrometer thick high thermal conductivity adhesive dielectric layer.

[0044] S5. Subsequent Production:

[0045] After the high-conductivity adhesive is laminated to the copper substrate, it goes through a pattern transfer process, an etching inspection process, a solder mask processing process, and finally passes the final inspection to obtain the finished product.

[0046] In steps S1-S5 above, the copper substrate needs to be wrapped in paper or coated with adhesive throughout the process to prevent the adsorption of fine particles from the outside.

[0047] In summary, as Figure 1 As shown, the manufacturing process of this single-sided dense circuit high thermal conductivity copper substrate involves first cutting out the copper substrate of the required size using a cutting device, and then using a grinding device to grind one side of the copper substrate to eliminate uneven areas. After grinding, observe whether the ground surface is clean, whether there are any bumps or small particles of impurities.

[0048] In the process of grinding the copper substrate, it is first secured and the surface to be ground is exposed. Several balls are embedded in the copper substrate in a ring shape around the perimeter. The top surface of the balls is the same thickness as the copper substrate after grinding. Then, the grinding disc is attached to the surface of the copper substrate for grinding until the grinding disc contacts the balls. At this time, the balls rotate in place due to friction, which does not delay the grinding operation of the grinding disc and also prevents the grinding disc from over-grinding and causing the copper substrate to become thinner.

[0049] Next, place the polished surface of the copper substrate on a flat table, hold down one corner of the copper substrate, and use a measuring device to obtain the diagonal lifting height. If the lifting height is greater than 0.75% of the total length of the copper substrate diagonal, it means that the flatness is not enough and it needs to be polished again. If the lifting height is less than 0.75% of the total length of the copper substrate diagonal, it means that the polishing is qualified.

[0050] If the height of the raised section is less than 0.75% of the total diagonal length of the copper substrate, further flatness testing is required to prevent concavity in the polished surface.

[0051] Further flatness testing includes the following steps:

[0052] The copper substrate is placed inside the box with the polished surface facing up. The box and the copper substrate fit together perfectly. A hydrophobic film is adsorbed onto the polished surface of the copper substrate using vacuum adsorption. A scraper is then inserted close to one side of the inner wall of the box. The scraper surface is hydrophobic, and the bottom of the scraper is attached to the surface of the copper substrate, i.e. the surface of the hydrophobic film. Water is poured into one side of the scraper and the scraper is moved. The scraper moves along the surface of the hydrophobic film. If water moves to the other side of the scraper during the movement, it indicates that the surface of the copper substrate has a concave area. If the water does not move to the other side of the scraper, it indicates that the surface of the copper substrate is flat.

[0053] Two flatness tests were conducted. The first test checked the overall flatness, and the second test checked for any concave surfaces that were not visible to the naked eye. This was done to avoid damage to the medium layer caused by unevenness or concave surfaces that were not visible to the naked eye.

[0054] Then, the copper substrate surface is browned using a browning solution to roughen the surface of the copper substrate and increase the bonding area.

[0055] Then, the polished surface of the copper substrate is brought into contact with the adhesive surface of the high-conductivity adhesive, so that the copper substrate and the high-conductivity adhesive are stacked, and then pressed together to firmly bond the high-conductivity adhesive and the copper substrate together.

[0056] Among them, the high thermal conductivity adhesive is a high thermal conductivity adhesive. Before bonding the high thermal conductivity adhesive to the polished surface of the copper substrate, it is necessary to confirm that the bonding surface of the high thermal conductivity adhesive is clean and free of cracks and small particles. The high thermal conductivity adhesive is the dielectric layer. The thickness of the high thermal conductivity adhesive is 50 micrometers. The heat generated by the light-emitting body of the product is quickly conducted through the 50-micrometer thick high thermal conductivity adhesive dielectric layer.

[0057] After the high-conductivity adhesive is laminated to the copper substrate, it goes through a pattern transfer process, an etching inspection process, a solder mask processing process, and finally passes the final inspection to obtain the finished product.

[0058] During the manufacturing process described above, the copper substrate needs to be wrapped in paper or coated with adhesive throughout its transfer between processes to prevent the adsorption of fine particles from the outside.

[0059] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A fabrication process for a single-sided, densely packed, high thermal conductivity copper substrate, characterized in that: The manufacturing process includes the following steps: S1. Cutting of bare copper plates: Cut copper plates to the required size using cutting equipment, and then use grinding equipment to grind one side of the copper plate to eliminate uneven areas. After grinding, observe whether the ground surface is clean, whether there are any bumps or small particles of debris. S2. Flatness inspection: Place the polished surface of the copper plate on a flat table, hold down one corner of the copper plate, and use a measuring device to obtain the height of the raised corner. If the raised height is greater than 0.75% of the total length of the diagonal of the copper plate, it means that the flatness is not enough and it needs to be polished again. If the raised height is less than 0.75% of the total length of the diagonal of the copper plate, it means that the polishing is qualified. In step S2, if the raised height is less than 0.75% of the total diagonal length of the copper plate, further flatness testing is required to prevent concave areas on the polished surface. The further flatness inspection includes the following steps: The polished copper plate is placed inside the box with the polished surface facing up. The box and the polished copper plate fit together perfectly. A hydrophobic film is adsorbed onto the polished surface of the polished copper plate using vacuum adsorption. A scraper is then inserted close to one side of the inner wall of the box. The scraper surface is hydrophobic, and the bottom of the scraper is attached to the surface of the polished copper plate, i.e., the surface of the hydrophobic film. Water is poured into one side of the scraper, and the scraper is moved. The scraper moves along the surface of the hydrophobic film. If water moves to the other side of the scraper during the movement, it indicates that the surface of the polished copper plate has a concave area. If the water does not move to the other side of the scraper, it indicates that the surface of the polished copper plate is flat. S3, Browning of Bright Copper Plates: The surface of the bright copper plate is roughened by using a browning solution to increase the bonding area. S4, High Adhesive Conductivity Pressing: The polished surface of the bright copper plate comes into contact with the adhesive surface of the high-conductivity adhesive, so that the bright copper plate and the high-conductivity adhesive are stacked, and then pressed together to firmly bond the high-conductivity adhesive and the bright copper plate together. S5. Subsequent Production: After the high-conductivity adhesive is laminated with the copper plate, it goes through a pattern transfer process, etching inspection, and solder mask processing process in sequence until it passes the final inspection, thus obtaining the finished product.

2. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In step S1, when grinding the copper plate, it is first tightened and the surface to be ground is exposed. Several balls are embedded in the copper plate in a ring shape around its perimeter. The top surface of the balls is the same thickness as the copper plate after grinding. Then, the grinding disc is used to grind the copper plate until it contacts the balls. At this time, the balls rotate in place due to friction, which does not delay the grinding operation of the grinding disc and also prevents the grinding disc from over-grinding and causing the copper plate to become thinner.

3. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In step S4, the high-conductivity adhesive is a high-thermal-conductivity adhesive.

4. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In step S4, before bonding the high-conductivity adhesive to the polished surface of the copper plate, it is necessary to confirm that the bonding surface of the high-conductivity adhesive is clean, without cracks, and free of small particles and debris.

5. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In step S4, the highly conductive adhesive is the dielectric layer.

6. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In step S4, the thickness of the highly conductive adhesive is 50 micrometers.

7. The fabrication process of a single-sided dense circuit high thermal conductivity copper substrate according to claim 1, characterized in that: In steps S1-S5, the copper substrate needs to be wrapped in paper or coated with adhesive for protection throughout the process of turnover.

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