CN102403299A - Circuit board structure and its manufacturing method - Google Patents

Abstract

The invention discloses a circuit board structure and a manufacturing method thereof, comprising the following steps: a layered body having at least one surface, the surface being provided with a circuit layer having a plurality of finger pads; the protruding parts extend from the finger pads and are formed between any two adjacent finger pads; and the solder mask layer is arranged on the layered body, the circuit layer, the solder finger pads and the protruding parts, the solder mask layer is provided with a plurality of openings so that the solder finger pads are correspondingly exposed out of the openings, and the protruding parts are positioned between any two adjacent solder finger pads so that the exposed surfaces of the solder mask layer corresponding to the protruding parts and other exposed surfaces are kept flat. The invention further provides a manufacturing method of the circuit board structure.

Description

Circuit board structure and its manufacturing method

technical field

The invention relates to a semiconductor device and its manufacturing method, especially to a circuit board structure and its manufacturing method.

Background technique

With the vigorous development of the electronic industry, electronic products are gradually moving towards the trend of multi-function and high performance. In order to meet the packaging requirements of high integration and miniaturization of semiconductor packages for more active and passive components and circuit loading, semiconductor packaging substrates have gradually evolved from double-layer circuit boards to multi-layer circuits. board (multi-layer board), so as to use interlayer connection technology (interlayer connection) in a limited space to expand the available circuit layout area on the semiconductor package substrate, and to meet the needs of integrated circuits with high circuit density, Therefore, the purpose of light, thin, small and small packages and improved electrical functions can be achieved.

US Patent No. 2008/0303131 and No. 2009/0068790 disclose a semiconductor device in which a plurality of chips are stacked on a packaging substrate. Each chip is electrically connected to a pad on the packaging substrate through a conductive element such as conductive glue. On the other hand, in order to make full use of the wiring space on the outermost layer of the package substrate, there are still wiring lines around the outermost solder finger pads, so it is necessary to use a solder mask layer such as green paint at the same time. Covering part of the surface of the circuit and the solder finger pad, and forming a solder mask opening in the solder mask layer that exposes part of the solder finger pad, so as to pass through the solder mask layer to protect the outermost circuit layer and solder finger The surface of the pad part is not oxidized by the air and moisture in the external environment. However, as shown in FIGS. 1A and 1B , when a depression 120 occurs on the surface of the package substrate, for example, a depression occurs on the surface of the solder resist layer between adjacent lines or between adjacent pads, it is easy for the conductive glue to flow to the depression. resulting in a short circuit due to bridging.

Please refer to the top view of the package substrate and the schematic cross-sectional view of the package substrate 10 covered with the solder resist layer shown in FIGS. In addition, each of the solder finger pads 110 is respectively extended with a circuit 112, and at least one pair of adjacent two solder finger pads 110a, 110b is provided with a circuit 112a; as shown in FIG. 1B, the package substrate 10 and the circuit layer 11 is covered with a solder resist layer 12 .

However, in the package substrate 10 covered with the solder resist layer 12 described above, the spacing between the lines 112 on the surface of the package substrate 10 varies from large to small (such as line segments D ₁ and D ₂ ), when the solder resist layer 12 After being covered on the packaging substrate 10 and the solder resist layer 12 is heated and cured, the solvent inside the solder resist layer 12 volatilizes, resulting in a depression 120 on the exposed surface (line segment D ₁ ) of the solder resist layer 12, especially the The larger the distance between the lines 112, the more obvious the depression 120 produced after the surface shrinkage of the solder resist layer 12 is, so the exposed surface of the solder resist layer 12 is not smooth, which is not conducive to subsequent packaging or easy to make the conductive adhesive Flow to the depression, causing a short circuit due to bridging.

In view of this, US Patent No. 6,692,988 discloses a packaging substrate capable of slowing down the sinking on the surface of the solder mask layer.

Please refer to FIGS. 2A and 2B , which are a top view of the package substrate of the above-mentioned US Patent No. 6,692,988 and a schematic cross-sectional view of the solder resist layer covering it. As shown in FIG. 2A, a circuit layer 11 is provided on at least one surface of a packaging substrate 10, and the circuit layer 11 has a plurality of pads 110. In addition, each pad 110 is individually extended with a circuit 112. Moreover, at least one dummy trace (dummy traces) 112c is provided between two adjacent traces 112a, 112b. As shown in FIG. 2B, the package substrate 10 and the circuit layer 11 are covered with a solder resist layer 12; thereby the corresponding covered solder resist layer 12 can be raised through these dummy lines 112c, so that the solder resist layer 12 The exposed surface can maintain better flatness.

However, under the requirement of high-density wiring, although the dummy line 112c can be used to raise the correspondingly covered solder resist layer 12 between these lines 112, the distance between these solder finger pads 110 is reduced, but it cannot be made The dummy line 112c passes between two adjacent solder finger pads 110, causing the solder resist layer 12 between these solder finger pads 110 to be easily sunken, and the distance between these adjacent solder finger pads 110 is too small , so it is easy for the conductive glue 113 to flow to the recess, as shown in FIG. 2C , resulting in a short circuit due to bridging.

Therefore, how to provide a circuit board structure and its manufacturing method, which can avoid the short circuit of the external electrical connection structure due to bridging, and can be applied to products with fine pitches, is an important issue.

Contents of the invention

In view of the various deficiencies of the above-mentioned prior art, the present invention provides a circuit board structure, comprising: a layered body; a circuit layer formed on the surface of the layered body, and the circuit layer has a plurality of welding finger pads and connecting the welding fingers conductive traces of pads, wherein at least one of any two adjacent pads has a protrusion extending toward the adjacent pad; and a solder resist formed on the layered body, conductive traces, finger pads and the protruding portion, and the solder resist layer has a plurality of openings exposing part of the surface of each of the pads.

The present invention further provides a method for manufacturing a circuit board structure, comprising: providing a layered body; forming a circuit layer on the surface of the layered body by a patterned manufacturing method, the circuit layer having a plurality of welding finger pads and connecting the welding fingers Conductive traces of pads wherein at least one of any two adjacent finger pads has a protrusion extending toward the adjacent finger pad; and overlying the layered body, conductive trace, finger pad and protrusion A solder resist layer is formed, and a plurality of openings are formed in the solder resist layer to expose part of the surface of each solder finger pad.

According to the above-mentioned circuit board structure and its manufacturing method, the layered body can be a circuit board with inner-layer circuits.

In addition, in one embodiment, protrusions are extended from the two adjacent pads, and the protrusions correspond alternately. These projections are in staggered correspondence. In addition, the circuit board structure and its manufacturing method of the present invention do not limit the shape of the protruding part, but generally the protruding part can be rectangular, triangular, semicircular or elliptical.

It can be seen from the above that the circuit board structure and its manufacturing method of the present invention are to make at least one solder finger pad extend with a protrusion on the surface of the layered body between any two adjacent solder finger pads, so that the subsequently formed solder resist layer The surface is kept flat to prevent conductive elements from forming on the solder finger pads due to depressions on the surface of the solder mask layer, resulting in bridging and short-circuiting of conductive elements. It can also ensure that the required build-up structure is of good quality, and can be applied to fine-pitch products. .

Description of drawings

1A to 1B are schematic cross-sectional views of a top view of an existing package substrate and its covering solder resist layer, wherein, FIG. 1B is a cross-sectional view of the section line 1B-1B in FIG. 1A;

2A to 2B are top views and schematic cross-sectional views of the package substrate of US Patent No. 6,692,988, wherein, FIG. 2B is a cross-sectional view of the line segment _D3 of the section line 2B-2B in FIG. 2A;

FIG. 2C shows a cross-sectional view of conductive glue bridging on section line 2C-2C of FIG. 2A; and

3A to 4B are schematic diagrams of the circuit board structure of the present invention and its manufacturing method, wherein, FIG. 3A is a cross-sectional view of FIG. 3B-1 at the section line 3A-3A; FIGS. 3B-1 to 3B-4 are different protrusions. An embodiment top view; and FIG. 4B is a top view of FIG. 4A.

Explanation of main component symbols

10 Package Substrate

11 Line layer

110, 110a, 110b Welding finger pads

112, 112a, 122b lines

112c false line

113 Conductive adhesive

12 Solder mask

120 Depression

20 Layered ontology

20a Surface

21 Line layer

210 Welding finger pad

211a, 211b, 211c, 211d protrusions

212 Conductive traces

22 Solder mask

220 opening

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification for the understanding and reading of those skilled in the art, and are not intended to limit the implementation of the present invention. Limiting conditions, so there is no technical substantive meaning, any modification of structure, change of proportional relationship or adjustment of size, without affecting the effect and purpose of the present invention, should still fall within the scope of the present invention. The disclosed technical content must be within the scope covered.

Please refer to FIGS. 3A to 4B , which illustrate a manufacturing method of a circuit board structure disclosed by the present invention.

As shown in FIGS. 3A and 3B-1 , firstly, a layered body 20 is provided. The layered body 20 can be a circuit board with internal circuits, and the circuit board can be a packaging substrate. A circuit layer 21 is formed on the surface 20a of the layered body 20 by a patterned manufacturing method. The circuit layer 21 has a plurality of pads 210 and conductive traces 212 connected to the pads 210. The conductive traces 212 can be connected to the layers. The inner circuit of the shape body 20 is electrically connected. In addition, as shown in FIG. 3B-1 , at least one of any two adjacent pads 210 has a protruding portion 211 a extending toward the adjacent pad 210 . Alternatively, as shown in FIGS. 3B-2 to 3B-4 , protrusions 211b , 211c and 211d are extended from the two adjacent pads 210 , and the protrusions 211b , 211c and 211d are alternately corresponding. In addition, the protruding part can have any shape, for example, the protruding part 211a (or 211b) is rectangular, as shown in Figures 3B-1 and 3B-2; or the protruding part 211c is triangular, as shown in Figure 3B-3 shown; or the protruding portion 211d is semicircular or oval, as shown in FIG. 3B-4.

As shown in FIGS. 4A and 4B , the layered body 20 , the conductive traces 212 , the pads 210 and the protrusions 211 a ( 211 b , 211 c or 211 d ) are covered with a solder resist layer 22 , and the solder resist layer 22 A plurality of openings 220 are formed, and part of the surface of the exposed finger pads 210 is correspondingly exposed to each of the openings 220, and these protrusions 211a (211b, 211c or 211d) are located between two adjacent welding finger pads 210, so that Make the protruding portion 211a (211b, 211c or 211d) raise the solder resist layer 22, so that the exposed surface of the solder resist layer 22 corresponding to these protruding portions 211a (211b, 211c or 211d) is kept flat with other exposed surfaces, Therefore, the exposed surface of the solder resist layer 22 is prevented from being sunken, which may lead to a short circuit due to conductive adhesive bridging in subsequent manufacturing methods, and thus can be applied to fine-pitch products.

The present invention further provides a circuit board structure, comprising: a layered body 20; a circuit layer 21 formed on the surface 20a of the layered body 20, and the circuit layer 21 has a plurality of welding finger pads 210 and is connected to the welding finger pads 210 conductive trace 212, wherein at least one of any two adjacent pads 210 has a protrusion 211a (211b, 211c or 211d) extending toward the adjacent pad 210; and a solder resist layer 22 is formed on the layered body 20, conductive traces 212, solder finger pads 210, and protrusions 211a (211b, 211c or 211d), and the solder resist layer 22 has a plurality of openings 220 to expose part of the surface of each solder finger pad 210 .

According to the above-mentioned circuit board structure, the layered body 20 can be a circuit board with internal circuits, and the circuit board can be a packaging substrate. In addition, the conductive traces of the circuit layer can be electrically connected with the inner circuit of the layered body.

In a specific embodiment, the two adjacent pads 210 are extended with protruding parts 211b, 211c or 211d, and the protruding parts 211b, 211c or 211d are alternately corresponding, as shown in FIGS. 3B-2 to 3B-4 . In addition, the protrusion can be rectangular, triangular, semicircular or elliptical, but not limited thereto.

The circuit board structure and its manufacturing method of the present invention are that a plurality of welding finger pads are formed on the circuit layer on at least one surface of the layered body, and at least one of any two adjacent welding finger pads is directed toward the adjacent welding finger pads. a protruding part is extended, and a solder resist layer is covered on the layered body, conductive traces, solder finger pads and protruding part, and a plurality of openings are formed in the solder resist layer, so that each of the solder finger pads is correspondingly exposed to the Each of the openings, so that these protrusions are located between any two adjacent solder finger pads, so that the exposed surface of the solder resist layer corresponding to these protrusions is kept flat with other exposed surfaces, so as to prevent conductive elements from being formed on the solder finger pads. Depressions on the surface of the solder resist layer lead to bridging and short-circuiting of conductive elements, which can ensure good quality of the build-up structure as required, and can be applied to fine-pitch products.

The above-mentioned embodiments are used to illustrate the principles and effects of the present invention, but not to limit the present invention. Any person skilled in the art can modify the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be as listed in the claims of this patent.

Claims (8)

1. A circuit board structure, comprising: layered body; A circuit layer is formed on the surface of the layered body, and the circuit layer has a plurality of solder finger pads and conductive traces connecting the solder finger pads, wherein at least one of any two adjacent solder finger pads is connected to the adjacent solder pad the finger pad is extended with a protrusion; and A solder resist layer is formed on the layered body, conductive traces, solder finger pads and protrusions, and the solder resist layer has a plurality of openings exposing part of the surface of each solder finger pad. 2. The circuit board structure according to claim 1, wherein the layered body is a circuit board with inner layers of circuits. 3 . The circuit board structure according to claim 1 , wherein protrusions are extended from the two adjacent pads, and the protrusions are staggered and corresponding. 4 . 4. The circuit board structure according to claim 1, wherein the protruding part is rectangular, triangular, semicircular or elliptical. 5. A method for making a circuit board structure, comprising: Provide a layered ontology; A circuit layer is formed on the surface of the layered body by a patterned manufacturing method, and the circuit layer has a plurality of solder finger pads and conductive traces connecting the solder finger pads, wherein at least one of any two adjacent solder finger pads is Adjacent pads extend with protrusions; and A solder resist layer is covered on the layered body, conductive traces, solder finger pads and protrusions, and a plurality of openings are formed in the solder resist layer to expose part of the surface of each solder finger pad. 6 . The method for manufacturing a circuit board structure according to claim 5 , wherein the layered body is a circuit board with inner layers of circuits. 7 . The manufacturing method of the circuit board structure according to claim 5 , wherein protrusions are extended from the two adjacent pads, and the protrusions are staggered and corresponded to each other. 8 . 8. The method for manufacturing a circuit board structure according to claim 5, wherein the protruding portion is rectangular, triangular, semicircular or elliptical.

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