TW593778B - A method for applying copper on substrates - Google Patents

Abstract

An arrangement produced by a method for plating of thick copper films on ceramic substrates that makes it possible to combine thick copper conductors with printed resistors, crossovers and/or other printed components in order to produce circuits for high current applications. The arrangement consists of a circuit board that includes a ceramic substrate (1) on which is applied a seed-layer of silver (2), a number of printed components (3, 4, 5, 6), a layer of autocatalytic copper (7) and thick copper conductors (9). The method implies that a conductor pattern in the form of a seed layer of silver is printed on the ceramic substrate, followed by the layer of autocatalytic copper. Thereafter a plating resist is applied followed by a copper plating of the non-protected areas. The plating resist is removed and the entire surface is etched down in order to remove superfluous copper.

Description

593778 A7 B7 'V. Description of the invention (1) The technical invention The present invention relates to a method for electroplating a thick copper film on a ceramic substrate, which combines a thick copper conductor with a printed resistor, a crossover, and other components. Possibly, and these components are used in the manufacture of high current applications circuits. BACKGROUND OF THE INVENTION In order to be able to manufacture competing DC / DC modules and / or other efficient and space-saving components such as for remote communication, it is important to find a dense circuit board manufacturing technology with low resistance conductors. This is usually achieved by the so-called thick film technology on the Taoxian substrate. To further save space and reduce costs, it is often desirable and necessary to incorporate printed resistors into circuit board patterns. One requirement is that the materials in the printed components are compatible with the circuit manufacturing process. The known techniques of circuit manufacturing mentioned above are either conductors with high current capacity without printed resistors, or conductors combined with printed resistors but with low to medium current capacity. The most common technology with a high current capacity circuit, that is, a thick copper film on the ceramic, refers to: _ • Directly bonded copper (DBC) • Copper clothing • High temperature thick film copper • Copper plating on thick film ( PCTF) _ Most of the above-mentioned technologies (except for copper plating on thick film (PCTF)), in order to adhere copper to ceramic substrates, which includes heat treatment at high temperatures, has been used so far It is difficult or impossible to combine thick copper conductors with printed resistors and crossovers. The copper-plating (PCTF) process on the thick film mentioned above has attracted special attention. -4- This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm) 593778 A7 B7 V. Description of the invention (2 'Especially the variant described in the existing US patent 5298687. The process in the mentioned puppet patent does not include any heat treatment of ceramic materials, but does require additional steps to apply a short-circuited conductor, the so-called It is difficult to remove the connection. In order to use the electroplating of ceramic substrates, a short circuit of this circuit is needed. The short-circuit link requires space, which leads to the reduction of the packaging density on ceramic substrates. Circuit with fewer substrates. The additional problem is that after the link is removed, the silver contact is exposed, and when exposed to moisture and voltage, silver may begin to migrate 'and cause the ceramic substrate' to The circuit is short-circuited. Therefore, an additional electroplating step containing nickel and / or gold is required to cover the exposed silver contact. SUMMARY OF THE INVENTION The problem mentioned above, for high current applications, has a strong force to obtain an f Thoughtful circuit A method for manufacturing a plate, a method for allowing thick copper conductors to be combined with printed resistors and / or other printed elements. The present invention relates to a method for copper plating with a thick film on a ceramic substrate. Thick copper conductors are printed with resistors, crossovers, and other components that can be used for making high-current applications. In addition, the present invention means that the final copper pattern is not sintered as in copper coating technology to Obtain its good adhesion to the ceramic substrate, and the rabbit prints the circuit pattern by removing the silver seed layer on the substrate, and the autocatalytic copper on it has a good adhesion. Not as thick film as mentioned Copper plating (PCTF) technology is used to print short-term silver links, but the circuit pattern can be covered with a thin layer of autocatalyzed copper to cover the entire surface of the substrate. This paper is suitable for financial standards @ 家 标准 (CNS) A # Specifications (21 () > < 297) Binding-5- B7 B7

5. Description of the invention (3), the area on the ceramic substrate where no further copper plating is performed, and then covered with a so-called plating protection layer. Subsequent plating forms the thickness of copper in the remaining areas. Since the circuit is connected before the final copper plating, there is no need for a temporary short-circuit connection or a so-called bus bar on the substrate. An advantage 3 of the present invention is that it saves space. & Another advantage is that since it is not necessary to consider the current into the link system, the present invention allows a large number of circuits on each ceramic substrate, thus making it possible to manufacture denser circuit boards. A further advantage is that, since there are no two conductors connected to the edge of the electro-mirror protective layer, it eliminates the risk of short circuit caused by unnecessary copper insulation failure. Finally, since the autocatalytic copper conductance is at least ten times better than that of a linked system such as copper plating on thick films (PCTF), a more uniform copper plating is achieved. With the present invention, the conductor achieves a conductor quality similar to that of copper-coated technology, while still maintaining the possibility of including standard thick film resistors and crossovers. Hereinafter, the present invention will be described in more detail with reference to the extended drawings. -Brief description of the drawings: Figure 1 illustrates a cross-sectional view of a substrate having a printed silver conductor and a number of printing elements. Fig. 2 illustrates a cross-sectional view of the same substrate as Fig. 1 with an autocatalytic copper application layer. Fig. 3 illustrates a cross-sectional view of the same substrate as in Fig. 2 with the application of a so-called plating protection layer and subsequent copper plating of an unprotected area. Fig. 4 illustrates a cross-sectional view of the substrate after removing the plating protection layer, as in Fig. 3. -6- This paper size applies to China National Standard (CNS) A4 (210X297 mm) 593778 A7 B7

V. Description of the invention (FIG. 5 illustrates the same substrate as that in FIG. 4. After the auto-catalytic copper is removed, the circuit board is manufactured according to the present invention. The description of the preferred embodiment of the present invention is based on the following. The described method 'Figure ^ outlines the process steps for manufacturing a circuit board on a ceramic substrate according to the present invention, where the circuit board has a thick conductor.% This method is performed on a ceramic substrate, The circuit pattern of the so-called silver seed sound 2 is printed to be introduced. Part of it is to obtain the good adhesion of the ceramic surface during the later period of ceramic-free electron microscopy, and part of it is to form the actual conductor pattern. This process is not limited to only containing silver. The seed layer, instead, can include any other material that has a good adhesion to the ceramic substrate, and at the same time, copper can be adhered to the surface of the substrate. As also illustrated in Figure 1, in this first step, For ceramic substrates, other printed elements 3, 4, 5, and 6 can be applied, such as resistors. After applying the silver seed layer 2 to the ceramic substrate, in order to leave the conductor pattern and the free surface of the substrate In order to cover the cathode, a micron-thick autocatalytic copper layer 7 is lowered, and the substrate is lowered into the chemical bath for a predetermined time. This is implemented to promote the short circuit of the subsequent circuit pattern, so it is further formed for subsequent electrolytic plating The thickness of the copper conductor is used to prepare a ceramic substrate. In the next over-private step, the thin plated protective layer 8 is applied to the area of the substrate 1 which is automatically catalyzed by copper, which does not provide a thick copper conductor, that is, It is the free surface of the substrate. This electroplated protective layer can be composed of a polymer material, such as epoxy resin or some other materials, which are used to make copper electric-7-This paper size applies to Chinese National Standard (CNS) A4 Specifications (210X297 mm) ---

Claims (1)

593778 A8 B8 C8 ----— D8-VI. Scope of Patent Application " ~ '---- *】 · -A method of electroplating copper conductor on M material, its features include _ steps:-silver conductor Pattern on ceramic substrate,-apply a layer of autocatalytic copper on the conductor pattern and the free surface of the remaining substrate,-apply an electroplated protective layer on the free surface of the substrate, a layer of autocatalytic copper. Copper-conductor auto-catalyzed copper layer,-removes the electroplated protective layer from the auto-catalyzed copper layer on the free surface of the substrate, and-removes the auto-catalyzed copper layer on the free surface of the substrate, and removes the conductive pattern from the conductor pattern. Remove a layer of copper. 2 · According to the scope of patent application! This method is characterized in that the autocatalytic copper layer on the free surface of the substrate and a layer of copper on the conductor pattern are removed by etching. 3. A configuration comprising a copper conductor plated on a ceramic substrate, characterized in that the copper conductor is produced by applying a conductor pattern of silver on the ceramic substrate, and applying a layer of autocatalytic copper on the conductor pattern and the substrate The rest of the free surface, an autocatalytic copper layer with a plating protection layer on the free surface of the substrate, an autocatalytic copper layer with a predetermined thickness of copper plated on a conductor, and a free surface from the substrate The autocatalytic copper layer removes the electroplated thin layer, and finally the autocatalytic copper layer is removed from the surface of the substrate, and the k-conductor pattern is used to remove the copper conductor of a specific thickness, so a ceramic substrate (1 ) Conductor pattern with silver applied on it (2), several printing elements-9- This paper size applies Chinese National Standard (CNS) A4 specification (210 × 297 mm) 593778 8 8 8 8 AB c D, scope of patent application (3, 4, 5, 6), a layer of autocatalytic copper (7) and a thick copper conductor (9). 4. > The configuration according to item 3 of the scope of patent application, characterized in that the autocatalytic copper layer on the free surface of the substrate and a layer of copper on the conductor pattern are removed by etching. -10- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)