Via hole conductor forming method and device of circuit substrate

Abstract

The invention provides a method for forming a via hole conductor of a circuit substrate, which comprises the following steps of: executing a glue injection process on a multi-layer soft board, and driving a glue injection device to move downwards to a position so that a plurality of glue injection pipes of the glue injection device correspondingly extend into a plurality of via holes of the multi-layer soft board and are separated from the bottoms of the via holes by a certain distance; driving the glue injection pipes of the glue injection device to output a certain amount of conductive glue respectively; and removing the glue injection device to form a cup-shaped via hole conductor in each via hole, the cup body of the cup-shaped via hole conductor being adhered to the inner peripheral wall of the via hole, and the cup rim flange of the cup-shaped via hole conductor being adhered to the periphery of the opening of the via hole.

Description

TECHNICAL FIELD

[0001] The present invention relates to a via conductor forming method of a circuit substrate, and more particularly to a via conductor forming method of a multilayer flexible board capable of avoiding bubbles from being covered on the via conductor. BACKGROUND

[0002] The conventional via conductor forming method of a multilayer flexible board includes:

[0003] (1) forming a plurality of vias on a multilayer flexible board by using a laser engraving process or an etching process;

[0004] (2) covering a layer of conductive adhesive on the multilayer flexible board; and

[0005] (3) performing a doctor blade coating operation on the layer of conductive adhesive by using a doctor blade device to form via conductors in the vias.

[0006] However, the conventional via conductor forming method of a multilayer flexible board has the following disadvantages: bubbles are covered on the via conductors during the forming process, causing the via conductors to be separated from the vias due to the expansion of the bubbles during a reflow process of the multilayer flexible board.

[0007] To solve the above problems, there is an urgent need in the art for a novel via conductor forming method. SUMMARY

[0008] It is an object of the present invention to provide a via conductor forming method of a circuit substrate, which can ensure that the via conductors formed on the circuit substrate are not covered with bubbles by using a non-closed adhesive injection operation, so that the via conductors are not separated from the vias due to the expansion of the bubbles during a reflow process of the circuit substrate.

[0009] It is another object of the present invention to provide a via conductor forming apparatus of a circuit substrate, which can provide a non-closed adhesive injection operation to ensure that the via conductors formed on the circuit substrate are not covered with bubbles, so that the via conductors are not separated from the vias due to the expansion of the bubbles during a reflow process of the circuit substrate.

[0010] To achieve the above objects, a via conductor forming method of a circuit substrate is also proposed, which includes performing an adhesive injection process on a multilayer flexible board, the adhesive injection process including:

[0011] driving a downward movement of an adhesive injection device to a position such that a plurality of adhesive injection tubes of the adhesive injection device correspondingly extend into a plurality of vias of the multilayer flexible board and are spaced apart from the bottoms of the vias by a distance;

[0012] driving each of the adhesive injection tubes of the adhesive injection device to output a certain amount of conductive adhesive; and

[0013] The glue injection device is removed to form a cup-shaped via conductor in each of the vias, a cup body of the cup-shaped via conductor adheres to an inner circumferential wall of the via, and a cup mouth flange of the cup-shaped via conductor adheres to a hole opening circumferential edge of the via.

[0014] In an embodiment, the vias are blind vias.

[0015] In an embodiment, the vias are through vias, and the bottom of the via is provided by a removable additional bottom plate of the multilayer soft board.

[0016] In a possible embodiment, the material of the conductive glue can be copper paste, silver paste, or tin paste.

[0017] In an embodiment, the vias of the multilayer soft board are formed through a laser cutting process.

[0018] In an embodiment, the vias of the multilayer soft board are formed through an etching process.

[0019] In an embodiment, the glue injection device has a heating function and a degassing function to remove bubbles in the conductive glue.

[0020] In an embodiment, the degassing function is achieved by a negative pressure operation.

[0021] To achieve the above-mentioned purposes, the present application further provides a via conductor forming device for a circuit substrate, which has a control circuit, a glue injection device, and a work platform, the control circuit is used to drive the glue injection device to perform a glue injection process on a multilayer soft board, the glue injection process includes:

[0022] Placing the multilayer soft board on the work platform, the multilayer soft board has a plurality of vias;

[0023] Driving the glue injection device to move downward to a position so that a plurality of glue injection pipes of the glue injection device correspondingly extend into the vias of the multilayer soft board and are separated from the bottoms of the vias by a distance;

[0024] Driving each of the glue injection pipes of the glue injection device to output a certain amount of conductive glue; and

[0025] Removing the glue injection device to form a cup-shaped via conductor in each of the vias, a cup body of the cup-shaped via conductor adheres to an inner circumferential wall of the via, and a cup mouth flange of the cup-shaped via conductor adheres to a hole opening circumferential edge of the via.

[0026] In an embodiment, the vias are blind vias.

[0027] In an embodiment, the vias are through vias, and the bottom of the via is provided by a removable additional bottom plate of the multilayer soft board.

[0028] In a possible embodiment, the material of the conductive adhesive can be copper paste, silver paste or tin paste.

[0029] In an embodiment, the via holes of the multilayer soft board are formed by a laser cutting process.

[0030] In an embodiment, the via holes of the multilayer soft board are formed by an etching process.

[0031] In an embodiment, the glue injection device has a heating function and a degassing function to remove air bubbles in the conductive adhesive.

[0032] In an embodiment, the degassing function is achieved by a negative pressure operation.

[0033] In order to enable the examiner to further understand the structure, features, purposes, and advantages of the present application, the drawings and detailed description of the preferred embodiments are as follows. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A block diagram showing an embodiment of a via hole conductor forming apparatus of a circuit substrate of the present application is shown;

[0035] Figures 2a to 2d A first embodiment of a glue injection process of the present application is shown;

[0036] Figures 3a to 3d A second embodiment of a glue injection process of the present application is shown; and

[0037] Figure 4 A main flowchart showing an embodiment of a via hole conductor forming method of a circuit substrate of the present application is shown.

[0038] In the above drawings, the meanings of the reference numerals are as follows:

[0039] 10: Multilayer soft board

[0040] 11: Via hole

[0041] 11a: Bottom

[0042] 20: Conductive adhesive

[0043] 21: Cup-shaped via hole conductor

[0044] 30: Removable additional bottom plate

[0045] 31: Concave portion

[0046] 100: Via hole conductor forming apparatus of a circuit substrate

[0047] 110: Control circuit

[0048] 120: Glue injection device

[0049] 121: glue injection tube

[0050] 130: work platform DETAILED DESCRIPTION

[0051] Referring to Figure 1 , a block diagram of an embodiment of a via conductor forming apparatus for a circuit substrate is shown. As shown in Figure 1 , a via conductor forming apparatus 100 for a circuit substrate has a control circuit 110, a glue injection device 120, and a work platform 130, the control circuit 110 being configured to drive the glue injection device 120 to perform a glue injection process on a multi-layer flexible board 10.

[0052] Referring to Figures 2a to 2d , a first embodiment of a glue injection process is shown. The glue injection process includes:

[0053] (I) placing the multi-layer flexible board 10 on the work platform 130 (as shown in Figure 2a ), wherein the multi-layer flexible board 10 has a plurality of vias 11, and the vias 11 have a bottom 11a, i.e., in this embodiment, the vias 11 are blind holes, and the vias 11 can be formed by a laser cutting process or an etching process;

[0054] (II) driving the glue injection device 120 to move downward to a position such that a plurality of glue injection tubes 121 of the glue injection device 120 correspondingly extend into the vias 11 of the multi-layer flexible board 10 and are spaced apart from the bottoms 11a of the vias 11 (as shown in Figure 2b ), wherein the glue injection device 120 is filled with a conductive glue 20, and the material of the conductive glue 20 can be copper paste, silver paste, or tin;

[0055] (III) driving the glue injection tubes 121 of the glue injection device 120 to each output a certain amount of conductive glue 20 (as shown in Figure 2c ); and

[0056] (IV) removing the glue injection device 120 to form a cup-shaped via conductor 21 in each via 11 (as shown in Figure 2d ), wherein the cup body of the cup-shaped via conductor 21 adheres to the inner peripheral wall of the via, and the cup mouth flange of the cup-shaped via conductor 21 adheres to the hole opening peripheral edge of the via 11.

[0057] In addition, the glue injection device 120 can further have a heating function and a degassing function to remove bubbles in the conductive glue 20, and the degassing function can be achieved by a negative pressure operation.

[0058] Referring to Figures 3a to 3d , a second embodiment of a glue injection process is shown. The glue injection process includes:

[0059] (I) placing a multi-layer soft board 10 on a work platform 130 (as shown in Figure 3a ), wherein the multi-layer soft board 10 has a plurality of through-holes 11 which can be formed by a laser cutting process or an etching process, and the multi-layer soft board 10 is provided with a removable additional bottom plate 30, and the removable additional bottom plate 30 has a plurality of recesses 31 to provide bottoms for the through-holes 11;

[0060] (II) driving a glue injection device 120 to move downward to a position such that a plurality of glue injection tubes 121 of the glue injection device 120 correspondingly extend into the through-holes 11 of the multi-layer soft board 10 and are spaced apart from the bottoms (recesses 31) of the through-holes 11 (as shown in Figure 3b ), wherein the glue injection device 120 is filled with a conductive glue 20, and the material of the conductive glue 20 can be copper paste, silver paste or tin;

[0061] (III) driving the glue injection tubes 121 of the glue injection device 120 to each output a certain amount of conductive glue 20 (as shown in Figure 3c ); and

[0062] (IV) removing the glue injection device 120 to form a cup-shaped through-hole conductor 21 in each through-hole 11 (as shown in Figure 3d ), wherein the cup body of the cup-shaped through-hole conductor 21 adheres to the inner circumferential wall of the through-hole, and the cup mouth flange of the cup-shaped through-hole conductor 21 adheres to the hole opening circumferential edge of the through-hole 11.

[0063] In addition, the glue injection device 120 can further have a heating function and a degassing function to remove bubbles in the conductive glue 20, and the degassing function can be achieved by a negative pressure operation.

[0064] From the above description, it can be seen that the present application discloses a through-hole conductor forming method of a circuit substrate. Please refer to Figure 4 , which shows the main flowchart of an embodiment of the through-hole conductor forming method of the circuit substrate of the present application, which is characterized by comprising a glue injection process, and the glue injection process comprises: driving a glue injection device to move downward to a position such that a plurality of glue injection tubes of the glue injection device correspondingly extend into a plurality of through-holes of a multi-layer soft board and are spaced apart from the bottoms of the through-holes (step a); driving the glue injection tubes of the glue injection device to each output a certain amount of a conductive glue (step b); and removing the glue injection device to form a cup-shaped through-hole conductor in each through-hole, wherein the cup body of the cup-shaped through-hole conductor adheres to the inner circumferential wall of the through-hole, and the cup mouth flange of the cup-shaped through-hole conductor adheres to the hole opening circumferential edge of the through-hole (step c).

[0065] In step a, the through-holes can be blind holes or through-holes, wherein when the through-holes are through-holes, the bottoms of the through-holes are provided by a removable additional bottom plate of the multi-layer soft board.

[0066] In addition, in step a, the via holes of the multilayer soft board can be formed by a laser cutting process or an etching process.

[0067] In addition, in step b, the conductive adhesive can be copper paste, silver paste or tin paste.

[0068] In addition, in step b, the glue injection device can have a heating function and a degassing function to remove bubbles in the conductive adhesive, and the degassing function can be achieved by a negative pressure operation.

[0069] According to the above design, the present application also has the following advantages:

[0070] First, the via hole conductor forming method of the circuit substrate of the present application can ensure that the via hole conductor formed on the circuit substrate is not covered with bubbles through a non-closed glue injection operation, so that the via hole conductor does not separate from the via hole due to bubble expansion in the reflow process of the circuit substrate; and

[0071] Second, the via hole conductor forming device of the circuit substrate of the present application can provide a non-closed glue injection operation to ensure that the via hole conductor formed on the circuit substrate is not covered with bubbles, so that the via hole conductor does not separate from the via hole due to bubble expansion in the reflow process of the circuit substrate.

[0072] The preferred embodiments disclosed herein are not intended to limit the scope of the present application. Any modifications or changes made to the technical ideas of the present application by those skilled in the art are within the scope of the present application.

Claims

1. A method of forming a via conductor of a circuit substrate, characterized by, The method comprises performing a glue injection process on a multi-layer soft board, the glue injection process comprising: lowering a glue injection device to a position such that injection tubes of the glue injection device correspondingly extend into through holes of the multi-layer soft board and are spaced apart from bottoms of the through holes by a distance; causing the injection tubes of the glue injection device to each output a certain amount of conductive glue; and removing the glue injection device to form a cup-shaped through hole conductor in each of the through holes, a cup body of the cup-shaped through hole conductor adhering to an inner circumferential wall of the through hole, and a cup mouth flange of the cup-shaped through hole conductor adhering to a hole opening circumferential edge of the through hole.

2. The via conductor forming method of a circuit substrate according to claim 1, wherein, The through holes are blind holes.

3. The method of forming a via conductor of a circuit substrate according to claim 1, wherein, The through holes are through holes, and the bottoms of the through holes are provided by a removable additional bottom plate of the multi-layer soft board.

4. The via conductor forming method of claim 1, wherein, The material of the conductive glue is selected from a group consisting of copper paste, silver paste, and tin paste.

5. The method of forming a via conductor of a circuit substrate according to claim 1, wherein, The through holes of the multi-layer soft board are formed by a laser cutting process.

6. The via conductor forming method of a circuit substrate according to claim 1, wherein, The through holes of the multi-layer soft board are formed by an etching process.

7. The method for forming a via conductor of a circuit substrate according to Claim 1, wherein, The glue injection device has a heating function and a deaeration function to remove bubbles in the conductive glue.

8. The via conductor forming method of claim 7, wherein, The deaeration function is achieved by a negative pressure operation.

9. A through hole conductor forming apparatus for a circuit substrate, having a control circuit, a glue injection device, and a work platform, the control circuit being used to cause the glue injection device to perform a glue injection process on a multi-layer soft board, the glue injection process comprising: placing the multi-layer soft board on the work platform, the multi-layer soft board having through holes; lowering the glue injection device to a position such that injection tubes of the glue injection device correspondingly extend into the through holes of the multi-layer soft board and are spaced apart from bottoms of the through holes by a distance; causing the injection tubes of the glue injection device to each output a certain amount of conductive glue; and removing the glue injection device to form a cup-shaped through hole conductor in each of the through holes, a cup body of the cup-shaped through hole conductor adhering to an inner circumferential wall of the through hole, and a cup mouth flange of the cup-shaped through hole conductor adhering to a hole opening circumferential edge of the through hole. The through holes are blind holes.

10. The via conductor forming apparatus for circuit substrates of claim 9 wherein, The through holes are through holes, and the bottoms of the through holes are provided by a removable additional bottom plate of the multi-layer soft board.

11. The via conductor forming apparatus for a circuit substrate of claim 9, wherein, The material of the conductive glue is selected from a group consisting of copper paste, silver paste, and tin paste.

12. The via conductor forming apparatus for a circuit substrate of claim 9, wherein, The through holes of the multi-layer soft board are formed by a laser cutting process.

13. The via conductor forming apparatus for a circuit substrate of claim 9, wherein, The through holes of the multi-layer soft board are formed by an etching process.

14. The via conductor forming apparatus for a circuit substrate of claim 9, wherein, The glue injection device has a heating function and a deaeration function to remove bubbles in the conductive glue.

15. The via conductor forming apparatus for a circuit substrate of claim 9, wherein, The deaeration function is achieved by a negative pressure operation.

16. The via conductor forming apparatus for a circuit substrate of claim 15, wherein, ​

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