TWI683041B - Annealing - Google Patents

Abstract

The present invention is an annealing process including the following steps: plating a substrate with a plating solution to form a metal conductive layer on the surface of the substrate, wherein the substrate has a predetermined annealing temperature, and the plating solution contains a solvent, a Metal ions and an additive; and contacting the metal conductive layer with a hot liquid, wherein the temperature of the hot liquid before the hot liquid contacts is substantially the predetermined annealing temperature. Due to the more uniform heating characteristics of the hot liquid, the annealing effect can be greatly improved and the generation of lattice defects can be avoided, so that when the metal conductive layer is subsequently etched to form a circuit layer, cracks or fractures will not occur due to excessive biting at the lattice defects And affect the electrical function, in order to improve the electrical quality and yield of the circuit layer.

Description

Annealing

The present invention relates to an annealing process, in particular, using a hot liquid to anneal a metal conductive layer to remove impurities in the metal conductive layer, reduce lattice defects of the metal conductive layer, and prevent subsequent formation of the metal conductive layer by etching Has cracks or breaks in the circuit layer.

The circuit board has circuit patterns for configuring various electronic components. It is a very important device for electronic related products, including hard circuit boards and soft circuit boards. With the increasingly powerful functions of electronic products, especially portable products, such as mobile phones, the requirements for light, thin, short and small are getting more and more strict, so hard circuit boards or soft circuit boards also need to be reduced in size, so The specific circuit pattern in the circuit layer must also reduce the line width/line spacing as much as possible, for example, less than 10um.

Traditionally, when manufacturing a circuit board, an electroplating copper layer is usually formed on the substrate by electroplating, and then a circuit layer with a specific circuit pattern is formed by an etching process. Since the plating solution used in the plating method will generate impurities during the plating process, it will be attached to the copper plating layer at the time of electroplating, that is, the grain boundary of the copper plating layer, so that lattice defects are generated, and the etching process During the process, pinhole-like voids are left in the grain boundaries. Therefore, the circuit layer of the electroplated copper layer generates pinholes due to pinhole-shaped voids, which affects the electrical characteristics. Even when a plurality of pinholes are arranged in a row, the circuit layer may break or crack.

Therefore, the conventional technology must use annealing and heat treatment to make the grain boundary smaller and exclude impurities, thereby preventing the problem of cracking and cracking of the circuit layer. Generally, a high-temperature furnace is used, which is maintained at 180°C for at least 1 hour, but the uniform heating of the high-temperature furnace is not good, which affects the effect of reducing the grain boundary, and the heating temperature is too high, especially the heating time is quite long, and the yield cannot be greatly improved .

Therefore, there is a great need for a new type of annealing treatment, which uses thermal fluid to anneal the metal conductive layer to remove impurities in the metal conductive layer, and to make the grain boundary of the metal conductive layer smaller, which can prevent subsequent formation of the metal conductive layer by etching Cracks or breaks in the circuit layer of Solve all the problems of the above conventional techniques.

The main object of the present invention is to provide an annealing process for improving electrical quality and yield, and preventing cracks or fractures in the circuit layer formed by the subsequent etching process. Specifically, the annealing treatment of the present invention mainly prepares a plating solution first, and the plating solution contains at least a solvent, metal ions, and additives. Next, the substrate is electroplated with an electroplating solution, so that a metal conductive layer is formed on the substrate, and impurities generated by the cracking reaction of additives in the electroplating solution are left in the grain boundaries of the metal conductive layer. Then, a hot liquid with a heating temperature is prepared, and the hot liquid may include an inorganic solvent and/or an organic solvent.

Then, the substrate with the metal conductive layer is contacted with hot liquid for annealing, and the impurities in the metal conductive layer are removed, so that the grain boundary of the metal conductive layer becomes smaller. Finally, the substrate with the metal conductive layer is dried.

The above-mentioned metal conductive layer can be used for subsequent etching to form a circuit layer with a specific circuit pattern, especially a circuit with fine line width/line spacing. Since the hot liquid itself is liquid, it has more uniform heating characteristics, which can greatly The annealing effect on the metal conductive layer is improved to make the grain boundary smaller, so no pinhole-like voids are left after impurities are removed. Therefore, the circuit layer does not cause cracks or fractures due to pinhole-shaped voids to affect the electrical function, thereby improving the electrical quality and yield of the circuit layer.

S10~S50‧‧‧Step

The first figure shows a schematic diagram of an annealing process according to an embodiment of the invention.

The embodiments of the present invention will be described in more detail below with reference to icons and component symbols, so that those skilled in the art can implement them after studying this specification.

Referring to the first figure, a schematic diagram of annealing treatment in an embodiment of the present invention. As shown in the first figure, the annealing process of the embodiment of the present invention mainly includes steps S10, S20, S30, S40, and S50 that are performed in sequence to improve electrical quality and yield.

Specifically, the annealing process of the present invention starts from step S10 to prepare a plating solution, wherein the plating solution may contain at least a solvent, metal ions, and additives. Preferably, the metal ion may be copper ion, and the additive may be a copper plating additive.

Next, step S20 is performed, and the substrate is electroplated using an electroplating solution, so that metal ions are reduced to a metal or alloy, such as a metal copper layer or a copper-containing alloy layer, and then a metal conductive layer is formed on the substrate. It should be noted that the metal conductive layer is composed of multiple metal crystals, and gradually grows during the formation, so that a grain boundary will be formed between adjacent metal crystals. Since the additive undergoes a cracking reaction during the plating process to generate impurities, the impurities are left in the grain boundaries of the metal conductive layer.

The substrate may include epoxy resin, polyphenylene oxide resin (PPO), polyimide (PI), or polypropylene (PP).

In step S30, a hot liquid is prepared, wherein the heating temperature of the hot liquid may be between 40 and 250°C, and the hot liquid may include an inorganic solvent and/or an organic solvent. In addition, the hydrothermal fluid may further contain inorganic salts.

Then, proceed to step S40, contact the substrate with the metal conductive layer to the hot liquid prepared in step S30 for annealing, and at this time, the metal crystals of the metal conductive layer gain energy and rearrange due to the heating effect of the hot liquid. In order to achieve a thermally stable state, when rearranging, the adjacent metal crystals will gradually move closer together, so that the impurities in the grain boundary of the metal conductive layer are pushed out and removed, and the grain boundary of the metal conductive layer Will become smaller. More specifically, the hot liquid can contact the metal conductive layer of the substrate by immersion, for example, the tank is filled with the hot liquid, and the substrate is directly bubbled into the hot liquid. Alternatively, a spraying method can also be used, for example, a spray head is used to spray the hot liquid evenly onto the metal conductive layer of the substrate. Also. The contact time of the circuit board with hot liquid is between 10 seconds and 30 minutes.

Finally, proceeding to step S50, the substrate with the metal conductive layer is dried to remove any liquid on the metal conductive layer, and then the annealing process of the present invention is completed. In addition, the temperature of the drying process may be between 80 and 150°C.

Since the hot liquid itself is liquid and has the characteristics of relatively uniform heating, it can greatly improve the annealing effect on the metal conductive layer. Therefore, the metal conductive layer after the annealing treatment of the present invention has a smaller grain boundary, especially the removed grain boundary Impurities are very suitable for subsequent etching processes to form high-quality circuit layers, especially lines with fine line width/line spacing, such as line width/line spacing less than 10um. Furthermore, since the grain boundary of the metal conductive layer in the present invention is small, and the grain boundary does not contain impurities, in the subsequent etching process, pinhole-shaped voids will not occur in the grain boundary, and thus the etching The circuit layer formed by the engraving process will not be cracked or broken due to the pinhole-shaped voids, which affects the electrical function, thereby improving the overall electrical quality and yield of the circuit layer.

In summary, the main feature of the present invention is that it can meet the requirements of the market for the line width/line spacing to be increasingly reduced. Furthermore, the annealing process of the present invention can provide a metal conductive layer with reduced grain boundaries. Moreover, the pinhole-shaped gaps without conventional technology can prevent the gaps from being connected together to cause the circuit pattern of subsequent circuit layers to break, which is quite conducive to market competition.

Since the technology of the present invention is not found in published journals, periodicals, magazines, media, and exhibition venues, it is novel and can be broken through the current technical bottlenecks for specific implementation, which is indeed progressive. In addition, the present invention can solve the problems of conventional technology, improve the overall use efficiency, and can achieve industrially useful value.

The above are only for explaining the preferred embodiments of the present invention, and are not intended to limit the present invention in any form, so that any modifications or changes made to the present invention under the same spirit of the invention , Should still be included in the scope of protection of the present invention.

S10~S50‧‧‧Step

Claims (10)

An annealing process includes the steps of: plating a substrate with a plating solution to form a metal conductive layer on the surface of the substrate, wherein the substrate has a predetermined annealing temperature and the plating solution contains a solvent, a metal ion and An additive; and contacting the metal conductive layer with a hot liquid, wherein the temperature of the hot liquid before the hot liquid contact is substantially the predetermined annealing temperature. According to the annealing process of claim 1 of the patent application scope, after the step of the hot liquid contacting the metal conductive layer, the step of drying the metal conductive layer is further included. According to the annealing process of claim 1, the step of heating the temperature of the hot liquid to the predetermined annealing temperature is further included before the step of contacting the metal conductive layer with the hot liquid. According to the annealing process of claim 1 of the patent application scope, in the step of plating the substrate with the plating solution to form a metal conductive layer on the surface of the substrate, the metal ions of the plating solution further include copper ions, and the additive It also contains a copper plating additive. According to the annealing process of claim 1 of the patent application scope, before the step of plating the substrate with the plating solution to form a conductive metal layer on the surface of the substrate, the substrate further includes epoxy resin and polyphenylene oxide resin (PPO) , Polyimide (PI) or polypropylene (PP). According to the annealing process of claim 1 of the patent application scope, in the step of the hot liquid contacting the metal conductive layer, the substrate and the metal conductive layer are immersed in the hot liquid. According to the annealing process of claim 1 of the patent application scope, in the step of the hot liquid contacting the metal conductive layer, the hot liquid is sprayed on the surface of the metal conductive layer. According to the annealing treatment in claim 1 of the patent application scope, wherein the predetermined annealing temperature is between 40 and 250°C. According to the annealing process of claim 1 of the patent application range, in the step of the hot liquid contacting the metal conductive layer, the contact time of the hot liquid contacting the metal conductive layer is further between 10 seconds and 30 minutes. According to the annealing process of claim 1 of the patent application scope, after the step of the hot liquid contacting the metal conductive layer, the step of drying the metal conductive layer is further included, wherein the drying temperature in the step of drying the metal conductive layer It is between 80 and 150°C.

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