CN101820721B - Substrate for circuit board, circuit board and method for manufacturing circuit board - Google Patents

Abstract

The invention discloses a base material for a circuit board, the circuit board and a manufacturing method of the circuit board. The circuit board comprises a substrate, a plurality of elastic bumps and a patterned circuit layer. The elastic bumps are arranged in a matrix manner and are arranged on the substrate. The patterned circuit layer is configured on part of the elastic salient points and part of the substrate.

Description

Substrate for circuit board, circuit board and method for manufacturing circuit board

technical field

The invention relates to a circuit board, in particular to the structure of a base material for the circuit board and its manufacturing method.

Background technique

Flexible circuit board or flexible circuit board is a kind of circuit board with soft organic material as the substrate, which can be applied in continuous dynamic bending products. At present, the electrodes of flexible circuit boards are mostly made of copper. In order to provide enough space to accommodate the glue required for bonding, the thickness of copper electrodes (or circuits) is usually as thick as 8 microns to 12 microns. However, because the thickness of the copper electrode is too thick, the flexibility is poor, and the difference in thermal expansion coefficient between it and the organic substrate is large, so the stress generated after bonding or bending will cause problems such as poor reliability of the circuit board. . In addition, in terms of technology, in the process of etching the copper layer to form the copper electrode, due to the thick copper layer, under the limitation of the etching angle, the etching spacing is too small, which will cause the bottom of the copper electrode to be unable to be completely etched and separated. Short circuit occurs, or the top area of the electrode is too small due to over-etching, which affects the conductivity. In order to avoid the occurrence of short circuits, generally, sufficient spacing must be maintained between the copper electrodes, which limits the development of miniaturization.

Patents related to flexible circuit boards include US Patent 7,250,575. However, the method of this patent is to change the original gold bump process on the IC side to the soft board process. In addition, US Patent No. 5,949,512 solves the problem of breaking the copper circuit due to the stress concentration caused by the difference in the Young's Module of the copper and the organic material when the soft board is bent through the design of the mechanism. In addition, US Patent No. 7,299,547 mainly replaces the original copper circuit with an organic elastic circuit to increase the reliability of the structure.

Contents of the invention

The invention provides a circuit board, which includes a substrate, a plurality of elastic bumps and a patterned circuit layer. The above-mentioned plurality of elastic bumps are arranged in at least one matrix and arranged on the substrate. The patterned circuit layer is disposed on a part of the plurality of elastic bumps and a part of the substrate.

The invention further provides a base material for a circuit board, which includes a substrate; and a plurality of elastic bumps arranged in at least one matrix and disposed on the substrate.

The present invention also proposes a method for manufacturing a circuit board. In the method, an elastic bump material layer is first formed on a substrate, and then the elastic bump material layer is patterned to form a plurality of elastic bumps arranged in at least one matrix. After that, at least one conductive layer is formed to cover the plurality of elastic bumps and the substrate. Thereafter, the conductive layer is patterned to form a patterned circuit layer covering a part of the plurality of elastic bumps and a part of the substrate.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a substrate for a circuit board according to an embodiment of the present invention.

FIG. 1A is a top view of a substrate for a circuit board in FIG. 1 .

FIG. 1B is a top view of another circuit board substrate of FIG. 1 .

FIG. 2A is a top view of a substrate for a circuit board according to another embodiment of the present invention.

FIG. 2B is a top view of a substrate for a circuit board according to yet another embodiment of the present invention.

3 is a schematic cross-sectional view of a substrate for a circuit board according to yet another embodiment of the present invention.

FIG. 4A is a perspective view of a circuit board according to an embodiment of the present invention.

FIG. 4B is a perspective view of a circuit board according to another embodiment of the present invention.

5A to 5E are schematic cross-sectional views of a manufacturing method of a circuit board of an integrated circuit, and these figures are cross-sectional views along the line V-V of FIG. 4A.

Explanation of reference signs

10, 10A, 10B, 10C, 10D, 10E: Substrates for circuit boards

12: Substrate 13: Elastic material layer

14: Elastic bumps 16: Conductive layer

16A, 16B: patterned circuit layer 16a: inner pin

16b: External pin 16c: Connecting part

18: Protective layer 20A, 20B: Circuit board

22: Patterned photoresist layer 24, 26, 30, 40, 50, 60: Matrix

W, W1, W2: Gap width h: Elastic bump height

V-V: hatching

Detailed ways

FIG. 1 is a schematic cross-sectional view of a substrate for a circuit board according to an embodiment of the present invention. FIG. 1A is a top view of a substrate for a circuit board in FIG. 1 . FIG. 1B is a top view of another circuit board substrate of FIG. 1 . FIG. 2A is a top view of a substrate for a circuit board according to another embodiment of the present invention. FIG. 2B is a top view of a substrate for a circuit board according to yet another embodiment of the present invention. 3 is a schematic cross-sectional view of a substrate for a circuit board according to yet another embodiment of the present invention.

Please also refer to FIG. 1 , the substrate 10 for a circuit board according to the embodiment of the present invention includes a substrate 12 and a plurality of elastic bumps 14 . The material of the substrate 12 includes an organic insulating material or an inorganic insulating material. The organic insulating material is, for example, polyimide (Polyimide, PI), polyethylene terephthalate (Polyethyleneterephthalate, PET). Inorganic insulating materials are, for example, glass or ceramics. The substrate 12 can be a flexible substrate or a rigid substrate

The function of the elastic bump 14 is like a "cushion", which can absorb the thermal stress caused by the difference in thermal expansion coefficient between various electronic components, as well as the mechanical stress during bonding, so the softer the elastic bump 14 is, the more firm it is. The more elastic, the more obvious the effect. The elastic bumps 14 are arranged in a matrix and disposed on the substrate 12 . In an embodiment, the elastic bumps 14 of the present invention are arranged in a single matrix, such as the matrix 24 of the substrate 10A for a circuit board in FIG. 1A or the matrix 26 of the substrate 10B for a circuit board in FIG. 1B . In another embodiment, as shown in FIG. 2A , the elastic bumps 14 of the substrate 10C for circuit boards can also be arranged in two separate matrices 30 , 40 . In FIG. 2A, the matrices 30, 40 may be the same or different. The same or different here means that the arrangement of the elastic bumps 14 in the matrix, the size, height, shape of the elastic bumps 14 or the width of the gap between the elastic bumps 14 are the same or different. Of course, the elastic bumps 14 can also be arranged in a plurality of matrixes separated from each other as required. In yet another embodiment, as shown in FIG. 2B , the elastic bumps 14 of the substrate 10D for circuit boards are arranged in two different matrices 50 , 60 adjacent to each other. The different matrices 50, 60 described here may refer to the arrangement of the elastic bumps 14 in the matrix 50, 60, the size, height, shape of the elastic bumps 14 or the gap width between the elastic bumps 14, In FIG. 2B , two matrices 50 and 60 with different arrangements of the elastic bumps 14 are used for illustration. Of course, the elastic bumps 14 can also be arranged in a plurality of adjacent matrices as required.

Regarding the arrangement of the elastic bumps 14 in the matrix, please refer to FIG. 1A. In an embodiment, the matrix 24 formed by the plurality of elastic bumps 14 of the present invention includes a sequence C1.....CN and a number row R1. ..RN, and any two adjacent columns, such as multiple bumps of C3 and C4 are aligned with each other, and any two adjacent rows, such as multiple bumps of R2 and R3 are also aligned with each other. In another embodiment, please refer to FIG. 1B , the matrix 26 formed by a plurality of elastic bumps 14 of the present invention includes, for example, a number of columns C1...CN and a number of rows R1...RN, and any phase Two adjacent columns, such as multiple bumps of C3 and C4 are staggered with each other, and any two adjacent rows, such as multiple bumps of R2 and R3 are also staggered with each other.

Please refer to FIG. 1 , FIG. 1A and FIG. 1B , in the embodiment, the size of the elastic bump 14 is, for example, 10 microns in diameter, but it is not limited thereto. The height h is at least 3 microns or above to provide enough space for accommodating the glue required for bonding. In addition, in this embodiment, the circular elastic bump 14 is used as an illustration, however, the shape of the elastic bump 14 is not limited thereto, and it can be square, rhombus, rectangle, polygon, oval wait. The materials of the elastic bumps 14 include organic materials or inorganic materials. The organic material can be insulating or conductive, such as polyimide (PI), polyethylene terephthalate (PET). Inorganic materials are, for example, glass or ceramics.

Please refer to FIG. 1 and FIG. 1A , in the matrix, the gap width W between the elastic bumps 14 is at least 5 microns or more, so as to provide sufficient flow space for the adhesive material during lamination. In an embodiment, in the matrix, the gap width W1 between any two adjacent columns, such as the elastic bumps 14 of C3 and C4, is the same as that of any two adjacent rows, such as the elastic bumps 14 of R2 and R3. The gap width W2 between them is substantially the same. In another embodiment, in the matrix, any two adjacent columns, such as the gap width W1 between the elastic bumps 14 of C3 and C4 are substantially the same, and any two adjacent rows, such as the elastic bumps of R2 and R3 The gap width W2 between the dots 14 is also substantially the same, but the gap width W1 is different from the gap width W2.

Please refer to FIG. 1 , in the above embodiment, the base material 10 for circuit boards includes a substrate 12 and a plurality of elastic bumps 14 , and the industry only needs to form a conductive layer 16 after obtaining the base material for circuit boards described above. And patterning the conductive layer 16 can form a circuit board with a patterned circuit layer.

Please refer to FIG. 3, in another embodiment, in addition to the substrate 12 and a plurality of elastic bumps 14, the base material 10E for the circuit board also includes at least one layer of conductive layer 16, which blankets the elastic bumps. 14 and the substrate 12 as a circuit layer. The material of the conductive layer 16 is, for example, metal or conductive polymer. Metals are, for example, copper, copper alloys, aluminum, silver, nickel, gold or titanium. The thickness of the metal layer can be adjusted according to the magnitude of the current, and the thickness is at least 0.1 micron or above, but not limited thereto. The conductive polymer is, for example, polyacetylene (Polyacetylene), polyaniline (Polyaniline; PANi), and polypyrrole (Polypyrrole). The thickness of the conductive polymer is at least 3 micrometers or above to provide enough space for the adhesive required for bonding. After obtaining the substrate 10A for the circuit board, the trader only needs to pattern the conductive layer 16 to form a circuit board with a patterned circuit layer.

FIG. 4A is a perspective view of a circuit board according to an embodiment of the present invention. FIG. 4B is a three-dimensional view of another circuit board according to another embodiment of the present invention.

Please refer to FIG. 4A or 4B, the circuit board 20A or 20B of the present invention, in addition to including the substrate 12 and a plurality of elastic bumps 14 arranged in a matrix as shown in FIG. 1A, 1B, 2A or 2B, also includes patterned The wiring layer 16A and the protective layer 18 are shown in FIG. 4A , or further include a patterned wiring layer 16B and the protective layer 18 , as shown in FIG. 4B . The patterned circuit layer 16A or 16B is disposed on part of the elastic bumps 14 and part of the substrate 12 . The protection layer 18 covers part of the patterned circuit layer 16A or 16B, the part of the elastic bump 14 not covered by the patterned circuit layer 16A or 16B, and part of the substrate 12 .

Please refer to Fig. 4A, the circuit board 20A of the present embodiment can be used as the carrier board of integrated circuit, and its patterned line layer 16A comprises inner pin 16a, outer pin 16b and connects inner pin 16a and outer pin 16b The connection part 16c. The protective layer 18 covers the connection portion 16c of the patterned circuit layer 16A, exposing the inner pin 16a and the outer pin 16b of the patterned circuit layer 16a, so that the inner pin 16a can be connected to the chip, and the outer pin 16b can Connect with other printed circuit boards or panels.

Please refer to FIG. 4B, the pattern of the circuit layer 16B patterned on the circuit board 20B of this embodiment, for example, has a plurality of parallel metal lines, but it is not limited thereto, so that the circuit board 20B can be used as a connection between electronic components. Connection board, or test board, such as IC test board, LCD panel test board.

The invention uses elastic bumps and conductive layers to make elastic electrodes. Elastic bumps can solve the problem of poor reliability caused by differences in the coefficient of thermal expansion (Coefficient of Thermal Expansion) between components after bonding electronic components.

5A to 5E are schematic cross-sectional views of a manufacturing method of a circuit board of an integrated circuit, and these figures are cross-sectional views along the line V-V of FIG. 4A.

Referring to FIG. 5A , a substrate 12 is provided. The material of the substrate 12 includes organic materials such as polyimide (PI) and polyethylene terephthalate (PET). The substrate 12 can be a flexible substrate 12 or a rigid substrate 12 . Next, the elastic material layer 13 is formed on the substrate 12 . The material of the elastic material layer 13 includes at least one organic material, such as polyimide (PI). The method of forming the elastic material layer 13 is, for example, a coating method or a pressing method. Afterwards, the elastic material layer 13 may be pre-baked as required to cure the elastic material layer 13 .

Then, referring to FIG. 5B , the elastic material layer 13 is patterned to form a plurality of elastic bumps 14 , and these elastic bumps 14 are arranged into two separate matrices 30 and 40 . When the elastic material layer 13 is a photosensitive organic material, the method of patterning the elastic material layer 13 is, for example, directly exposing and developing the elastic material layer 13 . So far, the production of the base material for the circuit board as shown in Fig. 1 above is completed.

Afterwards, referring to FIG. 5C , at least one conductive layer 16 is formed on the substrate 12 to cover the elastic bumps 14 . The material of the conductive layer 16 is, for example, metal or conductive polymer. Metals such as copper, copper alloys, aluminum, silver, nickel, gold, formed by methods such as sputtering (Sputter), evaporation (Evaporation) or other appropriate physical vapor deposition methods, or electroless plating (Electroless plating) , chemical vapor deposition (chemical vapor deposition, CVD) or other appropriate chemical deposition methods. The thickness of the metal conductive layer 16 is adjusted according to the magnitude of the current, and its thickness is, for example, 0.1 μm or above, but not limited thereto. The conductive polymer is, for example, polyacetylene (Polyacetylene), polyaniline (Polyaniline; PANi), and polypyrrole (Polypyrrole). The forming method is, for example, coating. The thickness of the conductive layer 16 of the conductive polymer is more than 3 micrometers, which provides enough space for accommodating the glue required for bonding. So far, the production of the base material for the circuit board as shown in Fig. 3 above is completed.

After that, referring to FIG. 5D , a photoresist layer (not shown) is formed on the conductive layer 16 . Thereafter, exposure and development are performed to pattern the photoresist layer 22 . Afterwards, the conductive layer 16 is patterned by using the patterned photoresist layer 22 as a mask to form a patterned wiring layer 16A covering part of the elastic bumps 14 and part of the substrate 12 . The patterned circuit layer 16A includes an inner lead 16a, an outer lead 16b, and a connecting portion 16c connecting the inner lead 16a and the outer lead 16b.

Then, referring to FIG. 5E , the patterned photoresist layer 22 is removed. After the patterned photoresist layer 22 is removed, the elastic bumps 14 of the matrix 30 and 40 still remain on the substrate 12, and a part of the elastic bumps 14 are covered by the patterned circuit layer 16A; Another part of the elastic bumps 14 is not covered by the patterned circuit layer. After that, a protective material layer 18 is formed on the substrate 12 . The material of the protective material layer 18 includes insulating materials, such as polymer materials, such as epoxy resin (Epoxy), and the forming method is, for example, screen printing.

The present invention uses elastic bumps and conductive layers to make elastic electrodes to replace the original copper electrodes on the known flexible circuit board. Because the original copper electrodes are discarded, the softness of the flexible circuit board is increased, so the post-bonding can be increased. and reliability when bending. Since the elastic bumps can provide sufficient height to accommodate the bonding adhesive, the required conductive layer is thinner, so the process has a greater tolerance for etching angles, and more fine patterns can be etched. The etching spacing is greatly reduced, and the electrode density is greatly increased. In addition, since the elastic bumps are arranged on the substrate in a matrix, they can be used in different circuit patterns, and thus have a wide range of applications. On the other hand, this technology can also be applied to rigid boards, and it can also be used as a test board in the testing field in addition to bonding. In addition, the process of the embodiment of the present invention can be improved by the existing production technology, so mass production can be achieved without further investment in large production equipment.

Although the present invention has been disclosed above with embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall prevail as defined by the appended claims.

Claims (13)

1. a circuit board comprises

Substrate;

A plurality of elasticity salient points are arranged with at least one matrix-style, are arranged on this substrate;

The line layer of patterning is disposed on the said elasticity salient point of first and on this substrate of part; And

Protective layer is on the said elasticity salient point of the second portion that be covered on the line layer of this patterning of part, the line layer that is not patterned covers and on this substrate of not covered by the said elasticity salient point of this second portion of part.

2. circuit board as claimed in claim 1, the material of wherein said elasticity salient point comprises at least a organic material.

3. circuit board as claimed in claim 1, wherein said elasticity salient point are to arrange with one or more matrix-style.

4. circuit board as claimed in claim 3, wherein said elasticity salient point are to arrange with a plurality of matrix-style, and said matrix is adjacent one another are or separation.

5. circuit board as claimed in claim 1, wherein the material of this substrate comprises at least a organic or inorganic insulating material.

6. circuit board as claimed in claim 5, wherein the substrate of this organic or inorganic insulating material comprises bendable substrate or rigid substrate.

7. circuit board as claimed in claim 1, wherein the line layer of this patterning comprises at least one conductive layer.

8. circuit board as claimed in claim 7, wherein the material of conductive layer comprises metal, alloy, conducting polymer or its combination.

9. the manufacturing approach of a circuit board as claimed in claim 1 comprises:

On this substrate, form this elasticity convex point material layer;

This elasticity convex point material layer of patterning is to form these a plurality of elasticity salient points of arranging with at least one matrix-style;

Form this at least one conductive layer, cover said elasticity salient point and this substrate; And

This conductive layer of patterning to form the line layer of this patterning, is covered on the said elasticity salient point and this substrate of part of this first.

10. the manufacturing approach of circuit board as claimed in claim 9, wherein the material of this elasticity convex point material layer comprises at least a organic material.

11. the manufacturing approach of circuit board as claimed in claim 9, wherein this elasticity convex point material layer be with the coating or the mode of pressing forms.

12. the manufacturing approach of circuit board as claimed in claim 9, wherein the material of the line layer of this patterning comprises at least one conductive layer.

13. the manufacturing approach of circuit board as claimed in claim 12, wherein the material of this conductive layer comprises metal, alloy, conducting polymer or its combination.

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