TW551016B - Circuit board manufacturing process of embedded resistor - Google Patents

Abstract

A circuit board manufacturing process of embedded resistor is disclosed. Firstly, etch the metal layer on the substrate to form a first circuitry trace, form plural resistive recess holes on the first circuitry trace, embed plural thin embedded resistors into the resistive recess holes, and electrically connect the first conductive trace to the side edge of the thin embedded resistor, electroplate a thin metal layer on the circuitry trace and the thin embedded resistor to form the second circuitry trace, then etch the second circuitry trace, so that the second circuitry trace can protrude out on top of the resistive recess hole, and is electrically with the top of the thin embedded resistor, so as to increase the electrical connection area of the first, second circuitry traces and the thin embedded resistor.

Description

551016 V. Description of the invention α) 1. Field of the invention: The present invention is a circuit board process of an embedded resistor, especially a circuitry directly on printed circuit boards (circuitry). Traces) circuit board process of implanting multiple embedded resistors (Resistors) 0 2. Background of the invention:

According to the advancement of technology and the miniaturization of electronic products, many electronic components and printed circuit boards are required to reduce the size or area. Therefore, the development trend of passive components in electronic components has gradually changed from traditional independent passive Components (Discrete Passives) are transformed into functional designs of Embedded Passives. The so-called embedded passive component refers to the structure of a passive component such as a resistor or a capacitor is pressed into a thin sheet, which is directly implanted in the printed circuit board during the manufacturing process of the printed circuit board to be integrated with the conductive lines above it. References are, for example, U.S. Patent Nos. 5, 07 9, 069, 5, 1 55, 655, 5, 161, 086, 5,261, 153, 5, 347, 258, and 5, 466, 892.

For embedded resistors, the resistance per unit thickness (Resistivity) is related to the characteristics of the material, and the resistance width is related to the conductor's ability to form a circuit (Patterning). Generally, the selected resistance material needs to have a high resistance (Electrical Resistivity) Low Temperature Coefficient of Resistivity (TCR) and capacitance

Page 4 551016 V. Description of the invention (2) Easy to process, there are currently two types of materials that can be used. The first is a metal composite film, such as NiP, NiWP, NiCr, and NiCrAlSi. The second is = thick film (Polymer Thick Film (PTF), such as Inductive Composite, and the traditional manufacturing method is to etch the metal wire layer of the printed circuit board, and then coat the passive material layer on the metal conductive layer. For the first material, methods such as electroplating, sputtering, electroless plating, or CVD can be used, while the second material is screen printing. the Lord. '' However, the disadvantage of the embedded resistor process is that the error variability is large. The error variability is mainly due to the mismatch between the resistance value of the component and the line impedance. This is caused by the error variability of the component itself, the series inductance of the component (Series (Inductance) and inductive resistance (inductive resistance) caused by the three, in which the series inductance and inductive reactance are relatively small, almost negligible. The error variability of the embedded resistance is a metal alloy thin film material. Although s' has a small error variability, it can only provide a low resistance value. The polymer thick film material is based on epoxy resin, so it can provide High resistance value, but large error variability, so how to solve high resistance value and low error variability has become an urgent problem to be overcome in the process. Taking carbon ink resistor 2 as an example, the top view on printed circuit board 1 is shown in Fig. 1. The printed circuit board is provided with a metal conductive circuit 3, and the carbon ink resistor 2 is electrically connected to the conductive circuit. 3 on 'Generally, in order to find low error variability, each carbon ink resistor 2 must be made into the same geometry to reduce the error variability to the maximum.

551016 V. Description of the invention (3) Small, but in the traditional manufacturing process, the carbon ink resistance 2 manufactured will have different geometries, as shown in Figure 2 A, B, C, D is the carbon ink resistance 2 The shape of the three-dimensional schematic diagram may even cause open contact with the conductive line, and the embedded resistor cannot be reworked at all, and a defective product is formed. The job of the inventor is to solve the above existing embedded resistor. The "missing in the manufacturing process" is an intensive research and cooperation with the application of science, and proposes another new type of embedded resistor circuit board manufacturing process, which can achieve nearly the same geometry, so that the error variation performance is minimized. Effectively address the aforementioned shortcomings. 3 · Summary of the invention: The main feature of the present invention is to provide a circuit board manufacturing process for embedded resistors. First, a metal layer is etched on the substrate above the insulating layer to form a first layer. A conductive circuit is formed with a plurality of resistance recesses in the first conductive circuit. Then embed the thin embedded resistor into the resistance recess, and ^ the first conductive line can be electrically connected to the side of the thin embedded resistor by honing the top of the thin embedded resistor so that The thin-type resistor can be close to the thickness of the first conductive circuit. = Later, electroplating one layer on the conductive line and the thin embedded resistor: coating-forming-the second conductive line 'on the second conductive line :::-anti-etching thin m, and reserve a less than The small hole of the concave hole of the resistor, so that the electrical circuit of Mi is engraved so that the first: the conductive circuit can protrude from the

Page 6551016 V. Description of the invention (4) Above the resistor recess, the second thin conductive line can be electrically connected to the thin embedded resistor to increase the first and second conductive lines and the thin layer. Electrical connection area for embedded resistors. Finally, the anti-etching film is peeled off from the second thin metal layer to form a circuit substrate with an embedded resistor. A second feature of the present invention is to provide a circuit board manufacturing process of the above-mentioned embedded resistor, and the circuit substrates obtained by the above steps are stacked together to form a multilayer printed circuit board. Another feature of the present invention is to provide a circuit board structure of an embedded resistor, which includes an insulating layer, a first conductive circuit layer, a plurality of thin embedded resistors, and a second conductive circuit layer, wherein the A first conductive circuit layer is disposed above the insulating layer and is provided with a plurality of resistance recesses. The plurality of thin embedded resistors are embedded in the resistance recesses and are electrically connected to the first conductive circuit layer. Two conductive circuit layers are arranged above the first conductive circuit layer and protrude from the resistance recess to the thin embedded resistor 坌 to electrically connect the upper portion of the thin embedded resistor so that the The first and second conductive circuit layers and the plurality of thin embedded resistors form an electronic circuit. In order to allow your reviewers to further understand the technology, means and functions adopted by the present invention to achieve the expectations, please refer to the following: (2) Detailed description and belief that the purpose, features and characteristics of the present invention, Π: : Introductory and knowledgeable, however, the drawings are provided for reference and explanation only and are not intended to limit the present invention.

551016 Jade and invention description (5) 4 · Detailed description of the preferred embodiment: The present invention mainly embeds embedded resistors in the manufacturing process of circuit boards, and minimizes the error variability of the embedded resistors. From the above background of the invention, it can be known that as long as all the embedded resistors are fixed in the same geometric shape, the minimum error variability can be obtained. Therefore, the present invention changes the process of the printed circuit board, and the present invention uses carbon The ink resistance is described as an example. The circuit board manufacturing process of the embedded resistor of the present invention is mainly used to form a circuit substrate 10 having conductive lines and integrating a plurality of thin resistors, and the structure of the circuit substrate 10 is three-dimensional. Please refer to FIG. 3 As shown, the circuit substrate 10 is a printed circuit board with a metal layer above it, the material of which can be a copper metal layer, and an insulating layer 1 丨 below, which can be an epoxy resin composite material. The metal layer is etched to form a first conductive circuit layer 12, which is disposed above the insulating layer 11. A plurality of resistance recessed holes 13 are opened therein, and a plurality of thin embedded resistors 14 are embedded in the resistance recessed holes 13. And is electrically connected to the first conductive circuit layer 12. A second conductive circuit layer 15 is arranged above the first conductive circuit layer 12, and the distribution pattern is the same as the first conductive circuit layer 12, and the second conductive circuit layer 15 also protrudes from the resistance recess 13, and To the top of the thin embedded resistor 14 to electrically connect the top of the thin embedded resistor 14, so that the first conductive line 12 and the second conductive line layer 15 and a plurality of thin embedded resistors can be electrically connected; The resistor 14 forms an integrated electronic circuit, and can fix the shape of all thin embedded resistors 14 to minimize error variability.

Page 8551016, description of the invention (6) As shown in FIG. 4 is a schematic side view of the circuit substrate of this embodiment, the process of the present invention first etches a metal layer above the circuit substrate 10 to form a first conductive circuit layer 12, and A plurality of resistance recesses 13 are buried in the first conductive circuit layer 12 to be buried in the resistors 4 and 4. Next, a plurality of thin embedded resistors 14 are embedded in the resistance recess. In this embodiment, the thin embedded resistors 14 are carbon ink resistors 2, as shown in Fig. 5 is the side of the embedded carbon ink resistors. As shown in the schematic diagram, this embodiment uses the screen printing method to embed the carbon ink resistor 2 into the resistance recessed hole 13, because the screen printing method may cause bubbles in the carbon ink or the carbon ink is insufficient, the present invention Print twice in the forward direction and in the direction to eliminate the bubbles in the carbon ink or make up the carbon ink, and then rub the ceramic ink resistor 2 above with a ceramic brush so that the carbon ink resistor 2 can communicate with the first conductive circuit layer 12 The thickness is similar, and because the shape of the resistance recess 13 is fixed, the shape of the carbon ink resistor 2 in the resistance recess 13 will also be fixed, and the first conductive circuit layer 12 can be electrically connected to the carbon. Side of Ink Resistor 2. Figure 6 is a schematic side view of the copper foil plated in Figure 5. Next, the circuit board 10 is further electrically bonded with a thin copper metal layer. The first conductive circuit layer 12 and the carbon ink resistor 2 Above, a second conductive circuit layer 15 is formed, and the distribution pattern of the second conductive circuit layer 15 is the same as that of the first conductive circuit layer 12 and covered with the carbon ink resistor 2. Next, an anti-etching film 16 is coated on the second conductive circuit layer 15, and a hole smaller than the area of the resistance concave hole 13 is reserved on the carbon ink resistor 2, and the last name is engraved on the carbon ink resistor 2. The second conductive circuit layer 15 is a schematic side view of the second conductive circuit as shown in FIG. This makes the second conductive line

Page 9551016 V. Description of the invention (7) " The road layer 15 can protrude above the carbon ink resistor 2 so that the second conductive circuit layer 15 can be electrically connected to the carbon ink resistor 2 to increase the The electrical connection area between the first electrical circuit layer 12 and the second conductive circuit layer Η and the thin embedded resistor η. Finally, the anti-etching film 16 is peeled from above the second conductive circuit layer 15 to complete the process of the present invention, as shown in Figure 8 is a schematic side view of the process after the process of the present invention is completed. In the present invention, the circuit substrates obtained in the above steps can be stacked and stacked to form a multilayer printed circuit board. The job is that the circuit board manufacturing process of the embedded resistor of the present invention can indeed provide a design that is quite different from the known one by the technology disclosed above, which can improve the overall use value, and it has not been seen in the publication or before the application. Public use, since it has met the requirements for invention patents, and filed an invention patent application according to law. However, the drawings and descriptions disclosed above are only examples of the present invention. Those skilled in the art can make other improvements based on the above description, and these changes still belong to the spirit of the invention and Within the scope of patents defined below.

Page 10551016 Brief description of enclosing type (1) Brief description of the drawing Figure 1 is a schematic view of the carbon ink resistor on the printed circuit one ® A, B, C, D 俜; circle one is the carbon ink The three-dimensional schematic diagram of the possible shape of the resistor. Figure two is a schematic perspective view of the circuit substrate structure of the present invention; Figure four is a schematic side view of the circuit substrate; Figure five is a schematic side view of the carbon embedded resistors in Figure four; Figure 5 is a schematic side view of copper plating; Figure 7 is a schematic side view of the etched copper foil of Figure 6; and Figure 8 is a schematic view of the side view after the process of the present invention is completed. (2) Description of invention drawing number: 1 printed circuit board 2 carbon ink resistor 3 conductive circuit 10 circuit board 11 insulation layer

12 First conductive circuit layer 1 3 Resistive recessed hole 14 Thin embedded resistor 15 Second conductive circuit layer 1 6 Anti-etching film

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Claims (1)

551016 6. Scope of patent application ^ A type of embedded circuit board manufacturing process is used to form a circuit board with conductive lines and integrated thin-type embedded resistors. The steps include: a. Provide a substrate with a metal layer above and an insulating layer below. The metal layer is etched to form a first conductive circuit, and a plurality of resistive recesses are formed in the first conductive circuit; b. Embedded in the thin type Embedded resistor into the resistance recess to fix the shape of the thin embedded resistor and enable the first conductive line to be electrically connected to the side of the thin embedded resistor; c · record A thin metal layer over the conductive line and the thin embedded resistor to form a second conductive line; and d. Etching the second conductive line over the thin embedded resistor to make the second conductive line Can protrude above the resistance concave hole, so that the second thin conductive line can be electrically connected to the thin embedded resistor, so as to increase the electrical conductivity of the first and second conductive lines and the thin embedded resistor Connection area. 2. The process of the embedded passive component circuit board manufacturing process described in item 1 of the scope of patent application, wherein the thin embedded resistor in step b is embedded in the resistive recess by screen printing. 3. The printed circuit board manufacturing process of the embedded passive component as described in item 2 of the scope of patent application, wherein the screen printing method is printed twice in the forward direction and the direction to eliminate the thin embedded resistor material. Of bubbles. 4. The circuit board manufacturing process for embedded passive components as described in item 1 of the scope of patent application, after step b, it further includes: & 1016 6. Scope of patent application The top of the thin embedded resistor is polished by ceramics so that the thickness of the thin embedded resistor can be close to the thickness of the first conductive line. The process of the embedded passive component circuit board process as described in item 1 of the patent application, after step C, further includes: coating an anti-etching film on the second conductive line, and applying the thin embedded type A small hole smaller than the concave hole of the resistor is reserved above the resistor. 6. The process of the embedded passive component circuit board manufacturing process described in item 1 or item 5 of the patent application, after step d, the method further includes: peeling off the anti-etching film from above the second thin metal layer . 7. The manufacturing process of the embedded passive component circuit board according to item 1 of the scope of the patent application, after step d, the method further includes using the circuit boards obtained in the above steps to be stacked together to form a multilayer printed circuit board. 8. The manufacturing process of the embedded passive component circuit board according to item 1 of the scope of the patent application, wherein the material of the metal layer and the thin metal layer is a copper metal layer. 9. The manufacturing process of the embedded passive component circuit board according to item 1 of the scope of the patent application, wherein the material of the insulating layer is an epoxy resin composite material. 10 · —A kind of circuit board structure of embedded passive components, including: an insulating layer; a second conductive circuit layer is arranged above the insulating layer, and a plurality of resistance recesses are formed therein; a plurality of thin embedded resistors are embedded Placed in the resistance recess and gas-connected to the first conductive circuit layer; and a second conductive circuit layer disposed above the first conductive circuit layer in the same distribution scheme as the first conductive circuit layer, And protruding the electricity Page 13 551016 6. The scope of the patent application is to block the recessed hole to the top of the thin embedded resistor to electrically connect the top of the thin embedded resistor, so that the first and second conductive circuit layers and a plurality of thin types Embedded resistors form an integrated electronic circuit. 11. The circuit board structure of the embedded passive component as described in item 10 of the scope of patent application, wherein the material of the insulating layer is an epoxy resin composite material. 12. The circuit board structure of the embedded passive component according to item 10 of the scope of patent application, wherein the material of the first conductive circuit layer and the second conductive circuit layer is a copper metal layer. Page 14