TW566069B - Method of fabricating multi-layer printed circuit board - Google Patents

Abstract

A method of fabricating a build-up multi-layer board includes providing a multi-layer board on which has at least a conductive layer and a conductive through hole. A photo resist layer is formed on the conductive layer, which has the pattern of a circuit and blind via pad. A conductive material, such as solder, is printed on the conductive layer and is then treated by reflowing, so as to be positioned on the blind via pad for electrical conductivity. The self-alignment of the conductive material applied on the fabrication of conductive blind via simplifies the process of a build-up multi-layer board. Next, the pattern of circuit is formed with the photo resist layer and the conductive blind via as an etching mask. Then an out-layer circuit is formed after the removal of the photo resist layer and the formation of an insulative layer.

Description

566069 V. Description of the invention (1) 1. [Technical field to which the invention belongs] The present invention relates to a method for manufacturing a multilayer circuit board, and more particularly, to a method for manufacturing a multi-layer multilayer board, which is self-aligned by using a conductive material Nature makes blind holes. 2. [The first printed system product platform is a single-panel, lightweight, and electronic seal exhibition, so it is a multi-layer multi-layer Density front technology.] The printed circuit board (PCB) is known as the mother of electronics. Embedded electronic components, providing the necessary components for relay transmission of all electronic products. Printed circuit boards can be slightly divided, double-sided and multi-layered. Due to the recent trend of electronic products to be small, thin, high-speed, high-performance, high-density, and low-cost, the mounting technology is also geared towards high pin count and refinement (fi ne). And the integrated printed circuit board is also moving toward high-density wiring, fine-line pinholes, complex, and thin plates. The main application technologies in terms of the number of layers are layer-up technology (b u i 1 d u p) and high-density interconnect technology (H i g h Interconnection, HDI) °

The so-called build-up method is based on the conventional laminated multi-layer board, and then the layer is laminated with adhesive-backed copper foil (RCC) or copper foil and film. The interconnection with the internal circuit board is Mi crovi a micro-blind hole. The first A to E are schematic cross-sectional views of a conventional multi-layer multilayer board. As shown in FIG. 1A, a multilayer board is provided, which includes a dielectric layer 1 2 6 between two copper foil boards 1 2 4. Using appropriate methods, such as mechanical drilling, a number of through holes 1 2 3 are made through the multilayer board. After that, hole copper 1 2 1 is plated in the through holes 1 2 3. Then, refer to the first B

566069 V. Description of the invention (2) In the present invention, a through-hole 123 (pass through hole (PTH)) is filled with a resin plug 孑 L (r s i η p 1 u g g i n g), and then copper 125 is plated thereon. After that, a photoresist layer is formed on the surface copper 1 25, and the pattern with the inner layer circuit is transferred to the photoresist layer. After the surface copper 1 2 5 and the copper foil plate 1 2 4 are etched, the photoresist layer is stripped. The remaining surface copper 1 2 5 and the copper foil plate 1 2 4 constitute the inner layer circuit, as shown in the first C diagram. Next, referring to the first D diagram, a dielectric layer 1 2 7 is first formed to cover the entire multilayer board. Then, using a suitable method, such as a laser drilling method, a blind hole L 128 (blind via) is formed before the upper surface of the multilayer board, above the through hole 1 2 3 and the lower square. Furthermore, as shown in the first E diagram, the multilayer conductive board is covered with a plated conductive layer and the blind holes 1 2 8 are filled. Finally, the conductive layer is pattern-transferred and etched to form lines 130 and conductive blind holes 129. Lei Zeng needs the board to use the same wet layer. The benefit is equal to the difference. The copper guide layer of the process is wrong. The hole system is changed. The blind hole plating system will be blindly transmitted to the trunk system. If it is passed, then, and the hole system, where you need to drill the hole, you need to save the cause, and then shoot the dry technique to prepare for the pass. Lei Ruoji has provided redundant guides due to the complexity of holes in the upper layer and other drilling holes. The air-tight fine mines with multiple steps and blind shots or multiple layers of blind holes on the upper layer are drilled outside the hole. For the system-based system and the mechanical system, the system is designed to be used for wet-adding and uploading to the machine. It is expected to increase the quantity, work volume, and production time. Fang Kai blindly made the first shot plus range. [Abstract] For the above, to simplify the complexity of the multilayer build-up process, this text

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Page 6 566069 V. Description of the invention (3) The invention provides a method for making a multilayer multilayer board, which directly forms a blind hole pattern with a photoresist, instead of the traditional laser drilling process, and saves the cost of the blind hole process. For simplifying the manufacturing process of the inner multi-layer board, the present invention provides a method for manufacturing a multi-layer multi-layer board, which directly forms a blind hole pattern by using a photoresist and uses a method of solder printing and reflow to make the conduction of the blind hole. For simplifying the conduction of through-holes or blind vias, the present invention provides a method for manufacturing a multilayer circuit board. The method is to conduct the conduction of vias by conducting conductive plug holes, and to make the conduction of blind vias by solder printing and reflow. Abandon the general wet process and turn-on process, and also save the area occupied by blind holes and through holes. The method root covers the surface of a line. Conductive material Conductive material Conductive blind hole and blind hole engraving. According to the above, the surface is provided. With at least the materials, examples, use it. In order to simplify the conductive connection, a multilayer board of the present invention forms a light and a blind layer. As printed, a material is used to remove the light, a hole pad, and a brushed electrical material are conductive. It provides a layer of money for the resistance layer, at least including A conductive via and a barrier layer are formed on the conductive layer, and have a pattern of (blind via pad) < tin on the conductive layer, and then the solder is located at the position of the blind hole pad. Manufacturing of multilayer boards. After that, a barrier is etched, a conductive layer line is formed, an insulating layer is formed, and a conductive layer is formed on the side of the board. The conductive layer includes at least one process to be used as an electrical connection to form a conductive layer and a photoresist layer to etch the insulating layer.

566069 V. Description of the invention (4) A patterned outer layer circuit is formed. Case big occasions. The real part is in the inch and the round, and the ruler is outside. The detailed knowledge of the three is recognized, depending on the degree of indeterminate depth, such as the limit, and the picture has a degree and the description is wide and finely cut. The detailed chart is shown with a length of 1 and the road should be included. The side-use layer should be applied in a clear manner, and the present invention is described in the following. The invention described in the present invention is a method for making a multilayer board, which is applied to a printed circuit board and includes two conductive layers. And a first dielectric layer, wherein the first dielectric layer is located between two conductive layers. Two photoresist layers are formed on the two conductive layers respectively, and the two photoresist layers expose a part of the two conductive layers. A conductive material is formed on the partially exposed two conductive layers, and then the conductive material is processed by reflow, so that the conductive material forms at least one conductive blind via (pos t) on any two conductive layers. i The second diagram is a schematic flow chart of a method for manufacturing an increased multilayer board according to the present invention. Referring to the second figure, the present invention provides a multilayer board (step 10). In one embodiment, the multilayer board includes a dielectric layer between two copper foil boards. Next, a through hole is drilled in the multilayer board by a suitable method, such as mechanical drilling (step 12). After that, the through-hole conduction and the copper plating process of the two copper foil plates are performed (step 14). In the present invention, the through hole is plugged by using a conductive material plug hole (p 1 u g g i n g) to replace the original wet process copper plating, which simplifies the conduction process of the through hole.

Page 8 566069 V. Description of the invention (5) Next, the inventor's pattern is used to make blind holes and lines in an appropriate manner, and the pattern of the road and the blind hole pad are respectively moved to directly form the blind holes. Print and Conductive Materials' and step 18). In the present invention, a conductive metal or alloy is printed on the position of the case. In an implementer, the position of the blind hole of the self-al ignment of the present invention compensates for the conduction of the blind hole formed by the printing connection and has self-alignment. The blind hole is completely turned on, and there is no need to use the photoresist to directly form the blind hole pad and the circuit (step 16). In one embodiment, a photoresist layer is formed on any two copper foil plates, and then the wires are transferred to the photoresist layer. Such a photoresist pattern can then be performed on the photoresist layer with a blind hole pattern. The reflow soldering of this conductive material (ref 1 〇w) (in the step of selective printing, the blind hole pattern material, the conductive material can be a low melting point gold, the conductive material is solder.) The problem lies in the use of conductive materials with self-alignment characteristics. When reflowing, the conductive materials can flow back to the accuracy problem. Through this step, one of the characteristics of the present invention lies in the design of photoresistive electrical materials. After printing and re-soldering, that is, after the traditional laser drilling and wet process conduction processes, the two copper foil plates are processed in an appropriate manner, such as etching, to etch out the circuit patterns on the two copper foil plates (step 20) Then, the photoresist is removed. Then, an appropriate method is used to form an insulating layer and an outer conductive layer on the multilayer board, and an outer layer circuit is formed on the outer conductive layer (step 2 2). Production of the invention Layered multilayer

Π 566069 V. Description of the invention (6) A schematic cross-sectional view. Referring to FIG. 3A, a multilayer board is provided, which includes a dielectric layer 26 between two copper foil boards 28, and a plurality of through holes 23 penetrating through the multilayer board. In the present invention, the multilayer board can be used as the inner layer of the multilayer circuit board, but it is not limited to this application, and a through hole 23 is made by a suitable method, such as a mechanical drilling method. Next, referring to FIG. 3B, in the present invention, the conductive wet material is used instead of the traditional wet process method, so that the through hole 23 has the conductive through hole 23 which is electrically conductive due to the conductive plug hole. One of the features of the present invention is that the conductive material is used to plug the hole to simplify the manufacturing process of the conductive through hole. It should be noted that, as long as it is suitable as a conductive material of a printed circuit board, it does not depart from the scope of application of the present invention. After that, a layer of copper 24 is plated on the two copper foil plates 2 8 ^ by a general copper plating method for subsequent use. Referring to FIG. 3C, a photoresist layer 32 is formed on the copper 24 first, and then the pattern having the lines 31 and the blind hole pad 30 is transferred to the photoresist layer 32. In the present invention, the 'through hole 23 has been filled with a conductive material' and a copper 24 is formed thereon, and a blind hole can be provided for position design. Therefore, the blind hole and the through hole 23 of the present invention can be overlapped and located in an up-and-down position. This saves the area occupied by the blind hole and the through hole 23 and improves the flexibility of circuit design. One of the features of the present invention is to use a photoresist layer having a pattern of lines and blind hole pads to expose the blind hole pads without the need to purchase an expensive laser drilling machine. · Referring to the third D diagram, the conductive material is selectively applied to the position of the blind hole pad 30 on the photoresist layer 32 by selective printing, and then the reflow (ref 1 〇w) method is used to make Conductive material aligns itself at the position of blind hole pad 30

Page 10 566069 V. Description of the Invention (7). One of the features of the present invention is that the conductive material is melted into a liquid when reflow is used, and the cohesive force of the liquid conductive material causes the conductive material to aggregate. Furthermore, the material of the blind hole pad 30, that is, the exposed copper 24, has a tensile effect on the conductive material, so that it is located at the position of the blind hole. In the present invention, the conductive material may be a metal or an alloy with a low melting point, such as solder (s ο 1 d e r), as long as it is applicable to the plugging process, it belongs to the application scope of the present invention. One of the features of the present invention is that the conductive material has self-alignment characteristics during reflow. Even if some deviations in selective printing cause the conductive material to remain on the photoresist, it can be aligned during reflow. The position of the blind hole pad 30 completes the conductive blind hole 40. Therefore, one of the features of the present invention is to make conductive blind holes by using printing and resoldering conductive materials instead of general laser drilling and wet processes. In addition, due to the characteristics of the solder, the thermal conduction of the conductive blind via of the present invention is also better than that of the conventional blind via. In addition, due to the self-aligning nature of the conductive material, the area required for the blind hole pad is smaller than that required for the conventional laser drilling process, so the wiring density of the inner layers of the multilayer board can be increased. Next, as shown in the third E diagram, with the photoresist layer 32 and the conductive blind hole 40 as a mask, the copper foil plate 28 and the copper copper layer 4 are etched, and then the photoresist layer 3 2 is removed. Then, the insulating layer 3 4 and the conductive layer are sequentially formed on the multilayer board, and then an outer layer circuit 38 is formed on the conductive layer. In the present invention, in consideration of the flatness problem caused by the conductive blind hole 40, after the insulating layer 34 is formed, a flattening (ρ ο 1 i s h i n g) step is performed first, and then the conductive layer is formed. One of the features of the present invention is that the conductive blind hole 40 is formed by self-alignment of the conductive material, and has a shape of an upward protrusion, which reduces the conductive blind hole 40 and

Page 11 566069 V. Description of the invention (8) The contact area of the conductive layer forming the outer layer circuit 38. Therefore, the reduction of the area of the outermost conductive pad above the conductive blind hole 40 contributes to the increase in the layout density of the outer circuit 38 or the component. In summary, the method of the present invention uses a conductive material to plug holes to simplify the manufacturing process of conductive vias; a photoresist layer with a pattern of lines and blind hole pads is used to form a blind hole pad, without using an expensive laser drilling machine Table; the use of conductive materials with self-alignment characteristics during reflow, making conductive blind holes; conductive blind holes formed using conductive materials, has better thermal conductivity and smaller upper contact area, which can improve the inner layer of the circuit The wiring density can reduce the area of the outermost conductive pad above. The above-mentioned embodiments are only for explaining the technical ideas and characteristics of the present invention. The purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. When the scope of the patent of the present invention cannot be limited, That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered by the patent scope of the present invention. ❿

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Claims (1)

The map guide. One hole layer of the package is provided with a blind blind electrical tool hole, and the through conductive layer is blind to guide and block a light-containing material, which is: package the material, the layer material is small, and the mouth resistance material is packaged to open the photoelectricity. The layer method of the guide method is based on the one-sided multi-conductor material of the slab and the screed board. The blind layer is blindly guided at the blind layer of the hole electrical layer, and the multi-light is blocked. The lesser party increases the supply and formation and back-to-back on the layer one to one welding position; the shape of the road is to make clothes} up} line} in the} from the abed species {板 {一 C 口 彳 料 一层Less open material 1 More than case electricity 566069 6. Application for patent scope 2. The method for making a multi-layer multilayer board such as the first scope of patent application, further includes: removing part of the conductive layer to form the circuit, the transfer The removing step uses the photoresist layer and the blind via as a mask; and removes the photoresist layer. 3. The method for manufacturing a multi-layer multilayer board according to item 1 of the patent application scope, wherein the step (a) further comprises: removing a part of the multilayer board to form at least one through hole in the multilayer board; The material hole fills the through hole for electrical conduction; and a third conductive material is plated on the through hole and the conductive layer. 4. The method for making a multi-layer multilayer board according to item 3 of the patent application scope, which Page 15 566069 6. The position of the blind hole in the scope of patent application is above the through hole. The multi-layer layer addition system of the French side should. In the form of a cover, a hole is used, and the hole layer is dead, and the electrical conduction is conducted. Hai = mouth = mouth and the material layer resistance i electro-optical item 3 leads the third line. In addition to the application, you should include the 5 packages, please refer to the special line) # C 中 C As the 6th in the range, Fan Li uses the method of inclusion. The square material of the sheet and the electric layer is more conductive and the first layer is the form item of the formation system. R-*-The item of the plate multi-formation layer production system that prints its method. One, --I contains the first package. . The material of the material is a special guide for gold and electricity. Please apply at one point if the low 7 or the metal melting point of the material is low or the material is soldered to make the board brush.-For the application method ： The board contains a layer of multi-layered seeding system. One layer of multi-layer light-blocking light is two holes. The layers of electrical conductivity are two by one and the other are separate from the bifurcated layer. Into electric form) ^) ab C two c the bit layer dielectric 1 第 = mouth layer conductance two dew exposure is divided ΚΓ Jet mouth on the material •, the electric layer conducts one to the second one of the component shape部} C 出 C Exposure to the upper layer and the upper layer of the first layer of electricity should be two to make the first one. Any material should be blinded in the hole. The first piece of electricity should be straightened to a square welding position. d C material electricity Page 16 566069 6. Application for Patent Scope 9. The method for making a multilayer board according to item 8 of the patent application scope further includes: removing part of the two conductive layers and the first dielectric layer to form at least one through hole in the Two conductive layers and the first dielectric layer; filling the through hole with a second conductive material for the purpose of electrical conduction; and plating a third conductive material between the through hole and the two conductive layers on. 10. The method for manufacturing a multilayer board according to item 8 of the scope of patent application, further comprising: removing a part of the two conductive layers to form a circuit line, and the removing step is based on the photoresist layer and the conductive blind hole as A mask; and removing the photoresist layer. 1 1. The method for manufacturing a multilayer board according to item 10 of the scope of patent application, further comprising forming a second dielectric layer on the conductive blind hole and the circuit line. 1 2. The method for manufacturing a multilayer board according to item 8 of the patent application, wherein the two conductive layers include two copper foil layers. 1 3. The method for manufacturing a multilayer board according to item 8 of the scope of patent application, wherein the first conductive material comprises a solder material, or a low melting point alloy material, or a low melting point metal material. 1 4. The method for making a multilayer board as claimed in item 8 of the patent application, wherein (c Page 17 566069 6. Scope of Patent Application) The step includes forming the first conductive material by printing. 1 5. A blind via structure is located in a multilayer board, the multilayer board has a multilayer board core, and the blind via structure includes: a bottom surface, which is connected to a first one relatively close to the core of the multilayer board On the conductive layer; a top surface connected to a second conductive layer relatively far away from the core of the multilayer board; and a convex arc surface caused by the cohesion of a blind hole material in which the bottom surface and the first surface The area where the conductive layer contacts is larger than the area where the top surface contacts the second conductive layer. 16. The conductive blind hole structure according to item 15 of the scope of patent application, wherein the material of the blind hole includes a solder material. 17. The conductive blind via structure according to item 15 of the patent application scope, wherein the material of the blind via comprises a low melting point alloy material. 18. The conductive blind via structure according to item 15 of the patent application scope, wherein the material of the blind via comprises a low melting point metal material. Page 18