CN100459077C - Method for manufacturing substrate - Google Patents

Abstract

The invention discloses a method for manufacturing a substrate. The substrate manufacturing method includes: providing a core board with inner layer circuits on the upper side and the lower side; forming an accommodating space at the core plate; embedding an element in the accommodating space and forming an insulating layer to cover the element, the core board and the inner circuit on the upper side and the lower side of the core board; forming a plurality of holes on the insulating layer to expose a plurality of electrodes of the device; forming a plurality of Through holes to penetrate the insulating layer and the core plate; forming a conductive film on the surface of the insulating layer and the side wall of the through hole; forming a conductive layer on the conductive film; patterning the conductive layer to form an outer layer circuit; and forming a solder mask layer on the outer layer circuit.

Description

Substrate manufacturing method

technical field

The invention relates to a method for manufacturing a substrate, in particular to a method for manufacturing a substrate embedded with passive components.

Background technique

With the advancement of communication and electronic products, thin, light, small and high-functional products have become the mainstream trend in the market. Reducing the size and number of components used has gradually become the focus of product design and application. System in Package (System in Package) has the advantages of reduced packaging area, high speed, short development time and low production cost, and has become the mainstream technology to replace traditional individual packaging systems. The whole system packaging is divided into two main axes of integrated substrate and high-density interconnection, among which the integrated substrate emphasizes the substrate

With high functionality and integration features, passive components are embedded in the substrate. In the final analysis, it is hoped that active components and light transmission channels can also be embedded in the substrate. High-density interconnection technology is emphasizing the use of special materials (such as nanomaterials) and manufacturing processes to reduce the interconnection pitch from the existing 160 microns to below 100 microns.

In the limited substrate space, designing active components by shrinking or embedding passive components to create more space is an important technology that manufacturers currently regard as modularization. Generally speaking, the package integration of embedded component substrate technology can be used to replace traditional discrete passive components (such as capacitors, resistors, and inductors, etc.), and use new functional polymer composite technology to coat passive components Cloth, screen printing, lamination, etching, etc., so as to be buried in the inner layer of the circuit board. The material and stacked structure of the inner layer can be selected according to the circuit characteristics and requirements of the actual application.

Traditionally, the passive components are stacked on the outside of the substrate (possibly on the upper and lower sides of the substrate). It is conceivable that this will have the disadvantage of a relatively large overall component thickness. In contrast, embedding passive components into the substrate has many advantages. In addition to saving the space on the surface of the substrate, the required surface area of the substrate is reduced and the thickness of the overall component is doubled. The components are embedded in the substrate to greatly reduce the solder joints of the circuit board, reduce the unnecessary parasitic effects generated by high frequency, and then improve the electrical response of the RF module at high frequency, and increase the efficiency and reliability of module manufacturing and assembly; Also due to the above advantages, the manufacturing cost is also greatly reduced.

With the current number of passive components increasing by 30% per year and the substrate area shrinking by 30% per year, it is imperative to update and replace traditional discrete passive components. Therefore, how to accurately embed components into the substrate to form a stable substrate structure has become one of the important research and development goals of related industries.

Contents of the invention

The object of the present invention is to provide a method for manufacturing a substrate, which includes: providing a core board (Core) with inner layers of circuits on the upper and lower sides; forming a receiving cavity (Receiving Cavity) at the core board; Embed the components in the space, and form an insulating layer to cover the components, the core board and the inner circuit on the upper and lower sides; form a plurality of holes in the insulating layer to expose the plurality of electrodes of the component; form a plurality of through insulation layer and core plate through hole (Through Hole); form a conductive film on the surface of the insulating layer and the sidewall of the through hole; form a conductive layer on the conductive film; pattern the conductive layer to form the outer layer circuit; and form the outer layer circuit Solder mask

The substrate manufacturing method provided by the invention can stably embed components, especially passive components, into the substrate. Substrates with embedded passive components have many advantages. For example, embedding passive components in a limited substrate space can not only reduce the thickness of the overall module, but also increase more space for active components, thereby improving the module versatility. Furthermore, because the passive components are embedded in the substrate, the solder joints of the circuit board are greatly reduced, and the unnecessary parasitic effects caused by high frequencies are reduced, thereby improving the electrical response of the RF module at high frequencies, and increasing the number of module fabrication and assembly. High efficiency and reliability, and because of the above advantages, the manufacturing cost is greatly reduced.

Description of drawings

1A to 1K illustrate a method of manufacturing a substrate with embedded components according to a preferred embodiment of the present invention.

Wherein, the reference signs are explained as follows:

10 core board 101 first surface

102 Second surface 11 Conductive layer on core board

12 Inner layer circuit 13 Accommodating space

14 Components 142 Electrodes

15 first insulating layer 16 second insulating layer

17 The first release paper 18 The second release paper

19 hole 21 through hole

23 Conductive film 24 First conductive layer

25 Second conductive layer 26 Outer layer circuit

27 Solder mask layer 27a The first solder layer

27b Second solder layer

Detailed ways

Please refer to FIGS. 1A-1K , which illustrate a manufacturing method of a substrate with embedded components according to a preferred embodiment of the present invention. First, a core board (Core) 10 is provided, as shown in FIG. 1A. Then, an inner circuit is formed on the upper and lower sides of the core board 10, as shown in FIG. 1B. In this embodiment, a conductive layer 11 can be plated on the first surface 101 and the second surface 102 of the core board respectively, and the material of the conductive layer 11 can be any metal. Here, a copper film can be selected as the conductive layer, and exposed , development and etching to pattern the conductive layer 11 to form the inner layer circuit 12 . The material of the core board can be glass fiber cloth or non-glass fiber cloth (such as ABF).

Next, a receiving cavity (Receiving Cavity) 13 is formed at the core board 10, as shown in FIG. 1C. There are many ways to form the accommodating space 13 , such as forming by using machine drilling. The actual size of the accommodating space 13 depends on the size of the components to be embedded in the substrate.

Then, an element (for example, a passive element such as a capacitor, an inductor, or a resistor) 14 is buried in the accommodating space 13, and an insulating part (ie, the first insulating layer 15 and the second insulating layer 16 mentioned later) is formed. The components 14 , the core board 10 , and the inner circuit 12 on the upper and lower sides of the core board 10 are covered. One of the possible implementation methods is as follows:

Firstly, the element 14 is arranged under the core board 10, so that the accommodating space 13 corresponds to the position of the element 14, and a first insulating layer 15 is provided under the element 14, and a second insulating layer is provided above the core board 10 16, as shown in Fig. 1D. Generally, materials that have not yet fully hardened (still have some fluidity) can be used as the first insulating layer 15 and the second insulating layer 16, so that the element 14 can be completely covered by the core board 10 and the first insulating layer 15 after pressing. And surrounded by the second insulating layer 16. Also because during the stacking process, the first and second insulating layers still have partial fluidity, it is therefore preferable to provide the first release paper 17 and the second release paper above the first insulating layer 15 and the second insulating layer 16 18, to avoid contamination of the lamination machine by the first and second insulating layers that have not yet fully hardened during the subsequent lamination process.

Afterwards, the above-mentioned stacked body is pressed through a pressing step, so that the element 14 is embedded in the accommodating space 13 , as shown in FIG. 1E . The pressing step is generally performed under high temperature and high pressure, so as to cure the first insulating layer 15 and the second insulating layer 16 . After the pressing step is completed, the first release paper 17 and the second release paper 18 can be removed. Wherein, the first insulating layer 15 and the second insulating layer 16 constitute an insulating layer, and the insulating layer covers the component 14 , the core board 10 and the inner circuit 12 after the pressing step.

Next, a plurality of holes 19 are formed in the insulating layer to expose a plurality of electrodes 142 of the device 14, as shown in FIG. 1F. In this embodiment, the hole 19 can be formed on the second insulating layer 16 by means of laser drilling, so as to expose the electrode 142 of the device 14 .

Then, a plurality of through holes (Through Holes) 21 are formed to penetrate through the second insulating layer 16, the core board 10 and the first insulating layer 15, as shown in FIG. 1G. In practical application, the through hole 21 can be formed by machine drilling.

Next, a conductive thin film 23 is formed on the surface of the insulating layer and the sidewall of the through hole 21, as shown in FIG. 1H. In practical application, the element shown in Fig. 1G can be sputtered (Sputter), except that a layer of conductive film 23 will be formed on the first insulating layer 15 and the second insulating layer 16, the sidewall of the through hole 21 It will also be covered with a layer of conductive film 23. The material of the conductive film can be metallic copper.

Then, a first conductive layer 24 and a second conductive layer 25 are formed on the conductive film 23, as shown in FIG. 1I. In this embodiment, the first conductive layer 24 and the second conductive layer 25 can be formed by plating, and the conductive film 23 on the sidewall of the through hole 21 will also be thickened at the same time. The material of the first conductive layer 24 and the second conductive layer 25 may be metal copper.

Next, the first conductive layer 24 and the second conductive layer 25 are patterned to form the outer circuit 26, as shown in FIG. 1J. Wherein, the outer circuit 26 of the substrate can be formed by steps such as exposure, development, and etching.

Finally, a layer of solder mask (Solder Mask) is formed on the outer circuit 26. As shown in the 1K figure, the first solder layer 27a and the second solder layer 27b are formed on the patterned first conductive layer 24 and the pattern respectively. on the second conductive layer 25.

According to the manufacturing method described in the above embodiments, components, especially passive components (such as capacitors, inductors or resistors) can be stably embedded in the substrate. Substrates with embedded passive components have many advantages. For example, embedding passive components in a limited substrate space can not only reduce the thickness of the overall module, but also increase more space for active components, thereby improving the module versatility. In addition, since the passive components are buried in the substrate, the solder joints of the circuit board will be greatly reduced, and unnecessary parasitic effects caused by high frequencies will be reduced, thereby improving the electrical response of the RF module at high frequencies, and increasing the number of module manufacturing and assembly. High yield and reliability; also because of the above advantages, the manufacturing cost is greatly reduced.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the implementation scope of the present invention; that is, all equivalent changes and modifications made according to the claims of the present invention are covered by the patent scope of the present invention.

Claims (7)

1. A method for manufacturing a substrate, characterized in that the method comprises the following steps: providing a core board, the upper and lower sides of the core board have an inner circuit; forming an accommodating space at the core plate; Embedding an element in the accommodating space, and forming an insulating layer to cover the element, the core board and the inner layer circuits on the upper and lower sides, wherein the step of embedding the element in the accommodating space includes The element is correspondingly disposed under the core board and corresponds to the accommodating space; a first insulating layer is provided below the element; a second insulating layer is provided above the core board; providing a first release paper and a second release paper on the side away from the component from the second insulating layer to form a stack; and pressing the stack to embed the component in the accommodating space ; after pressing the stacked body, further comprising the step of removing the first release paper and the second release paper; and the first insulating layer and the second insulating layer constitute the insulating layer, in the pressing step Then coating the element, the core board and the inner circuit; forming a plurality of holes at the insulating layer to expose a plurality of electrodes of the element; forming a plurality of through holes to penetrate the insulating layer and the core board; forming a conductive film on the surface of the insulating layer and the sidewall of the through hole; forming a conductive layer on the conductive film; patterning the conductive layer to form an outer circuit; and A solder resist layer is formed on the outer circuit. 2 . The manufacturing method of the substrate according to claim 1 , wherein a metal layer is respectively formed on the upper and lower sides of the core board, and then the metal layer is exposed, developed, and etched to form the inner circuit. 3 . The manufacturing method of the substrate according to claim 1 , wherein the through hole is formed by mechanical drilling to penetrate through the insulating layer and the core board. 4 . 4. The manufacturing method of the substrate according to claim 1, wherein the conductive thin film is formed on the sidewall of the through hole by sputtering. 5 . The manufacturing method of the substrate according to claim 1 , wherein the conductive layer is formed on the conductive film by electroplating. 6. The manufacturing method of the substrate according to claim 1, wherein the component is a passive component. 7. The manufacturing method of the substrate according to claim 6, wherein the passive element is a capacitor, an inductor or a resistor.

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