A method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board

Abstract

The present invention provides a method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board, comprising the following steps: feeding material → manufacturing L1-L2 inner layers of a PTFE sheet → manufacturing L3-L4 inner layers of an FR4 sheet → laminating → primary drilling → high-pressure washing → primary electroplating → primary dry film → primary etching → browning → solder mask → visible ink printing → silver electroplating → ink removal → secondary dry film → secondary etching → molding → V-CUT → testing → AVI → packaging; before the step of manufacturing the L3-L4 inner layers of the FR4 sheet, the FR4 sheet is baked to release stress; after manufacturing internal circuits of the FR4 sheet, a plurality of slots are milled in a non-circuit coverage area to release stress, and a plurality of first positioning holes are opened; the expansion and contraction ratio of the FR4 sheet is recorded by equipment testing for use in the laminating step; the manufacturing steps are improved, the probability of layer deviation and board warping is reduced, and the quality of the mixed-pressure circuit board is improved.

Description

Technical Field

[0001] The invention relates to the field of circuit board processing, and in particular to a method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board. Background Art

[0002] The Chinese patent application publication number is CN 109862703 A, and the application publication date is June 7, 2019. It discloses a positioning method for the production of mixed-pressed boards, which includes the following steps: S1: cutting; S2: internal drilling, designing a mother-and-daughter board positioning hole program, drilling a first positioning hole group in the daughter board, drilling a second positioning hole group in the mother board, and drilling a third positioning hole group in the PP board through the mother-and-daughter board positioning hole program; S3: internal engraving, producing the inner layer graphics of each of the daughter boards and the mother board and etching the inner layer; S4: pressing, fixing the mother board, each of the daughter boards, and each of the PP boards with pins and placing them in a pressing machine for pressing; S5: removing the pins. Compared with related technologies, the present invention controls the positioning accuracy of the motherboard and the daughterboard, and the alignment accuracy of the motherboard and the daughterboard positioning holes, ensuring that the alignment accuracy error of the daughterboard and the motherboard after lamination is less than or equal to 3.6 mil, and the alignment accuracy error between the daughterboards is less than or equal to 3.6 mil, thereby improving the alignment accuracy of the motherboard and the daughterboard in the mixed press board. In actual production, the technical defects of this existing technology are: because ordinary FR4 is a thermosetting material and PTFE is a thermoplastic material, layer deviation and board warping problems still occur due to stress during lamination. In view of this situation, it is urgent to improve. Summary of the Invention

[0003] In response to the above problems, the present invention provides a method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board, which improves the manufacturing steps, reduces the probability of layer deviation and board warping, and improves the quality of the mixed-pressure circuit board.

[0004] To achieve the above object, the present invention solves it through the following technical solutions:

[0005] A method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board, comprising the following steps: material feeding → manufacturing the L1-L2 inner layer of a PTFE sheet → manufacturing the L3-L4 inner layer of an FR4 sheet → pressing → one drilling → high-pressure washing → one electroplating → one dry film → one etching → browning → solder mask → ink printing → silver electroplating → ink removal → secondary dry film → secondary etching → molding → V-CUT → testing → AVI → packaging;

[0006] Before the L3-L4 inner layer step of the FR4 board is fabricated, the FR4 board is baked to release stress. After the internal circuits of the FR4 board are fabricated, a plurality of slots are milled in the non-circuit coverage area to release stress, and a plurality of first positioning holes are opened. The expansion and contraction ratio of the FR4 board is recorded by equipment testing for use in the lamination step.

[0007] After the step of making the L1-L2 inner layer of the PTFE sheet, a plurality of second positioning holes are opened corresponding to the positions of the first positioning holes; the expansion and contraction ratio of the PTFE sheet is recorded by equipment testing for use in the pressing step;

[0008] Before the lamination step, the FR4 sheet and the PTFE sheet are positioned by positioning pins, and the lamination operation is performed according to the expansion and contraction ratio of the FR4 sheet and the PTFE sheet that has been tested and recorded; hot-melt is performed twice; after the lamination is completed, the positioning pins are removed;

[0009] The one-time drilling step uses a colorful coated drill bit to drill holes; the stacked plate structure during drilling is, from top to bottom, aluminum sheet, FR4 plate, PTFE plate, bare base plate, and pad;

[0010] In the solder mask step, the electrostatic spraying operation needs to be completed within 6 hours after the etching is completed;

[0011] In the secondary dry film step, a wet film is first used as a primer, a thin layer of ink is applied to the inner layer, and then the dry film is pressed and then exposed and developed.

[0012] Preferably, after the drilling step, the plate needs to be subjected to a plasma debonding operation, and the plate after plasma debonding needs to complete an electroplating step within 5 hours.

[0013] Preferably, in the high pressure washing step, 60kg / cm 2 High-pressure cleaning is carried out with water pressure of 2.5m / min.

[0014] Preferably, before the browning step, two pieces of plain copper plates are placed in to check for scratches on the plate surface, and the browning step is started only after it is confirmed that there are no scratches.

[0015] Preferably, in the primary film drying step and the secondary film drying step, micro-etching is used as pre-treatment, and the conveying speed is 2.0 m / min; after the pre-treatment, the film is pressed within 2 hours, and the pressing speed is 2.5 m / min.

[0016] Preferably, in the ink printing step, the pre-baking condition is set to 80°C / 30min, and the post-baking condition is set to 150°C / 20min.

[0017] Preferably, in the de-inking step, alkaline etching is used for de-inking, and the de-inking speed is set to 4.0 m / min.

[0018] The beneficial effects of the present invention are: the stress of the FR4 sheet is released in advance by baking and grooving, and then the expansion and contraction ratio of the FR4 sheet and the PTFE sheet is tested and recorded by the equipment for use in the pressing step, thereby effectively reducing the probability of board warping, and then pressing is performed by cooperating with the positioning pin and the first positioning hole and the second positioning hole, thereby effectively reducing the layer deviation problem that occurs during the pressing process, thereby improving the quality of the mixed-pressed circuit board. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0020] A method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board, comprising the following steps: material feeding → manufacturing the L1-L2 inner layer of a PTFE sheet → manufacturing the L3-L4 inner layer of an FR4 sheet → pressing → one drilling → high-pressure washing → one electroplating → one dry film → one etching → browning → solder mask → ink printing → silver electroplating → ink removal → secondary dry film → secondary etching → molding → V-CUT → testing → AVI → packaging;

[0021] Before the L3-L4 inner layer step of the FR4 board is fabricated, the FR4 board is baked to release stress. After the internal circuits of the FR4 board are fabricated, a plurality of slots are milled in the non-circuit coverage area to release stress, and a plurality of first positioning holes are opened. The expansion and contraction ratio of the FR4 board is recorded by equipment testing for use in the lamination step.

[0022] After the step of making the L1-L2 inner layer of the PTFE sheet, a plurality of second positioning holes are opened corresponding to the positions of the first positioning holes; the expansion and contraction ratio of the PTFE sheet is recorded by equipment testing for use in the pressing step;

[0023] Before the lamination step, the FR4 sheet and the PTFE sheet are positioned by positioning pins, and the lamination operation is performed according to the expansion and contraction ratio of the FR4 sheet and the PTFE sheet that has been tested and recorded; hot-melt is performed twice; after the lamination is completed, the positioning pins are removed;

[0024] The one-time drilling step uses a colorful coated drill bit for drilling; the stacked plate structure during drilling is aluminum sheet, FR4 plate, PTFE plate, bare substrate, and pad from top to bottom; after the one-time drilling step, the plate needs to be plasma debonded, and the plate after plasma debonding needs to complete an electroplating step within 5 hours.

[0025] In the high pressure washing step, 60kg / cm 2 High-pressure cleaning is carried out with water pressure of 2.5m / min.

[0026] In the solder mask step, the electrostatic spraying operation needs to be completed within 6 hours after the etching is completed;

[0027] Before the browning step, place two pieces of copper plates in to check for scratches on the plate surface. Only after confirming that there are no scratches can the browning step begin.

[0028] In the secondary dry film step, a wet film is first used as a primer, a thin layer of ink is applied to the inner layer, and then the dry film is pressed and then exposed and developed.

[0029] In the primary drying step and the secondary drying step, micro-etching is used as pre-treatment, and the conveying speed is 2.0 m / min; after the pre-treatment, the film is pressed within 2 hours, and the pressing speed is 2.5 m / min.

[0030] In the ink printing step, the pre-bake condition was set to 80°C / 30min, and the post-bake condition was set to 150°C / 20min.

[0031] In the de-inking step, alkaline etching is used for de-inking, and the de-inking speed is set to 4.0 m / min.

[0032] In this embodiment, the stress of the FR4 sheet is released in advance by baking and grooving, and then the expansion and contraction ratio test of the FR4 sheet and the PTFE sheet is recorded by the equipment for use in the pressing step, effectively reducing the chance of board warping, and then pressing is performed by cooperating with the positioning pins and the first positioning holes and the second positioning holes, effectively reducing the layer deviation problem that occurs during the pressing process, thereby improving the quality of the mixed-pressure circuit board.

[0033] The above embodiment merely represents one embodiment of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board, comprising the following steps: Material delivery → production of L1-L2 inner layer of PTFE sheet → production of L3-L4 inner layer of FR4 sheet → pressing → one drilling → high pressure washing → one electroplating → one dry film → one etching → browning → solder mask → ink printing → silver plating → ink removal → second dry film → second etching → molding → V-CUT → testing → AVI → packaging; its characteristics are: Before the L3-L4 inner layer step of the FR4 board is fabricated, the FR4 board is baked to release stress. After the internal circuits of the FR4 board are fabricated, a plurality of slots are milled in the non-circuit coverage area to release stress, and a plurality of first positioning holes are opened. The expansion and contraction ratio of the FR4 board is recorded by equipment testing for use in the lamination step. After the step of making the L1-L2 inner layer of the PTFE sheet, a plurality of second positioning holes are opened corresponding to the positions of the first positioning holes; the expansion and contraction ratio of the PTFE sheet is recorded by equipment testing for use in the pressing step; Before the lamination step, the FR4 sheet and the PTFE sheet are positioned by positioning pins, and the lamination operation is performed according to the expansion and contraction ratio of the FR4 sheet and the PTFE sheet that has been tested and recorded; hot-melt is performed twice; after the lamination is completed, the positioning pins are removed; The one-time drilling step uses a colorful coated drill bit to drill holes; the stacked plate structure during drilling is, from top to bottom, aluminum sheet, FR4 plate, PTFE plate, bare base plate, and pad; In the solder mask step, the electrostatic spraying operation needs to be completed within 6 hours after the etching is completed; In the secondary dry film step, a wet film is first used as a primer, a thin layer of ink is applied to the inner layer, and then the dry film is pressed and then exposed and developed.

2. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: After the drilling step, the plate needs to be subjected to a plasma debonding operation, and the plate after plasma debonding needs to complete an electroplating step within 5 hours.

3. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: In the high pressure washing step, 60kg / cm 2 High-pressure cleaning is carried out with water pressure of 2.5m / min.

4. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: Before the browning step, two pieces of plain copper plates are placed to check for scratches on the plate surface. The browning step is started only after it is confirmed that there are no scratches.

5. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: In the primary film drying step and the secondary film drying step, micro-etching is used as pre-treatment, and the conveying speed is 2.0 m / min; after the pre-treatment, the film is pressed within 2 hours, and the pressing speed is 2.5 m / min.

6. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: In the ink printing step, the pre-bake condition is set to 80°C / 30min, and the post-bake condition is set to 150°C / 20min.

7. The method for manufacturing a four-layer Teflon high-frequency mixed-pressure circuit board according to claim 1, characterized in that: In the de-inking step, alkaline etching is used for de-inking, and the de-inking speed is set to 4.0 m / min.