WO2021248586A1

WO2021248586A1 - Manufacturing method for lcp substrate

Info

Publication number: WO2021248586A1
Application number: PCT/CN2020/099310
Authority: WO
Inventors: 陈康; 陈勇利; 韩佳明
Original assignee: 瑞声声学科技(深圳)有限公司; 瑞声精密制造科技(常州)有限公司
Priority date: 2020-06-09
Filing date: 2020-06-30
Publication date: 2021-12-16
Also published as: CN111629526B; CN111629526A

Abstract

Disclosed is a manufacturing method for an LCP substrate. The manufacturing method for the LCP substrate comprises: providing an inner-layer circuit board and an outer-layer circuit board; etching the inner-layer circuit board, and releasing a copper-layer circuit; sputtering the inner-layer circuit board by means of plasma; performing micro-etching treatment on the sputtered inner-layer circuit board; and laminating the inner-layer circuit board and the outer-layer circuit board which are subjected to the micro-etching treatment to form the LCP substrate.

Description

Manufacturing method of LCP substrate

Technical field

The present invention relates to the technical field of circuit boards, in particular to a manufacturing method of an LCP substrate.

Background technique

With the rapid development of 5G communications and millimeter waves, the demand for high-frequency and high-speed FPCs continues to increase. At present, the main high-frequency substrates used in the industry are mainly LCP (Liquid Crystal Polymer (liquid crystal polymer) substrate, and the production of LCP multilayer board requires a lamination process, in order to improve the interlayer bonding force, the copper foil needs to be roughened.

At present, the pre-treatment of LCP non-adhesive pressing is mainly blackening or browning, and a dense passivation layer is formed on the copper surface to enhance the bonding force of the inner layer of the multilayer board. However, browning or blackening will generate copper oxides while increasing the roughness of the copper surface, which will cause the conductivity of copper to deteriorate.

Therefore, it is necessary to provide a method for manufacturing an LCP substrate to solve the above-mentioned problems.

technical problem

The purpose of the present invention is to disclose a manufacturing method of an LCP substrate.

Technical solutions

The object of the present invention is achieved by adopting the following technical solutions: a manufacturing method of an LCP substrate, the manufacturing method of the LCP substrate includes: providing an inner layer circuit board and an outer layer circuit board; etching the inner layer circuit board to release the copper layer Circuit; Sputtering the copper layer circuit of the inner layer circuit board by plasma; microetching the copper layer circuit of the inner layer circuit board after sputtering; the inner layer circuit board and the outer layer circuit after the microetching treatment The outer circuit board of the board is laminated to form an LCP substrate.

Preferably, the step of plasma sputtering the copper layer circuit of the inner layer circuit board includes: plasma sputtering the surface of the copper layer circuit to roughen the surface of the copper layer circuit.

Preferably, the step of the micro-etching treatment includes: performing micro-etching on the surface of the roughened copper layer circuit to form a microscopic roughening.

Preferably, the micro-etching is to place the inner circuit board in a micro-etcher, and use a micro-etching solution for etching treatment, the micro-etching solution includes sulfuric acid, sodium persulfate and copper ions; the concentration of the sulfuric acid is 3 %-5%, the content of sodium persulfate is controlled within 50g/L-70g/L, and the content of copper ions is less than 25g/L.

Preferably, the step of the microetching treatment further includes: washing the copper layer of the inner layer circuit board after the microetching with water; and acid washing the copper layer of the inner layer circuit board after the water washing to remove the copper. Layer of oxide on the surface of the circuit.

Preferably, in the pickling step, a sulfuric acid solution with a concentration of 3% to 5% is used for pickling at a temperature of 25°C to 35°C.

Preferably, the step of the microetching treatment further includes: washing the copper layer lines of the inner layer circuit board after the acid washing with water; and performing anti-oxidation treatment on the copper layer circuits of the inner layer circuit board after the water washing to remove the inner layer. Pickling liquid on the surface of the circuit board.

Preferably, the anti-oxidation treatment is an anti-oxidation treatment of the inner layer circuit board in a room temperature environment by using an anti-oxidant.

Preferably, the step of the micro-etching treatment further includes: washing the inner layer circuit board after the anti-oxidation treatment; drying the inner layer circuit board after the water washing, and the temperature of the drying treatment is 75 ℃ to 85℃.

Preferably, in the step of pressing the microetched inner layer circuit board and the outer layer circuit board to form the LCP substrate, the inner layer circuit board is pressed against the outer layer circuit board within 24 hours after plasma sputtering. combine.

Beneficial effect

Compared with the prior art, in the present invention, plasma sputtering and micro-etching treatment cooperate with each other to improve the roughness of the copper layer circuit. The advantage of this method is that while increasing the roughness of the copper layer line, it does not introduce oxides to the copper layer line.

Description of the drawings

FIG. 1 is a schematic flow chart of the manufacturing method of the LCP substrate provided by the present invention.

Fig. 2 is a schematic diagram of the structure of the inner layer circuit board provided by the present invention.

FIG. 3 is a schematic diagram of the structure of the inner layer circuit board provided by the present invention after ionomer sputtering.

4 is a schematic diagram of the structure of the inner layer circuit board provided by the present invention after microetching.

FIG. 5 is a schematic diagram of the structure of the inner layer circuit board pressed and bonded with the outer layer circuit board after micro-etching provided by the present invention.

Embodiments of the present invention

The present invention will be further described below in conjunction with the drawings and embodiments.

It should be noted that all directional indicators (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relationship between components in a specific posture (as shown in the accompanying drawings). If the relative position relationship, movement situation, etc. change, the directional indication will change accordingly.

It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be a centering element at the same time. When an element is said to be "connected" to another element, it can be directly connected to the other element or an intermediate element may be present at the same time.

In addition, the descriptions related to "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on what can be achieved by a person of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist. , Is not within the protection scope of the present invention.

Please refer to FIGS. 1 to 5. FIG. 1 is a schematic flow chart of the manufacturing method of the LCP substrate 100 provided by the present invention, FIG. 2 is a schematic structural view of the inner layer circuit board 10 provided by the present invention, and FIG. 3 is the inner layer provided by the present invention. The schematic diagram of the structure of the circuit board 10 after ion sputtering. FIG. 4 is a schematic diagram of the structure of the inner layer circuit board 10 provided by the present invention after microetching, and FIG. 5 is a schematic view of the structure of the inner layer wiring board 10 provided by the present invention after microetching.

The present invention provides a manufacturing method of the LCP substrate 100. The manufacturing method of the LCP substrate 100 includes at least the following five steps.

S101: Provide an inner layer circuit board 10 and an outer layer circuit board 20.

The LCP substrate 100 of the present application is a multilayer circuit board. The LCP substrate 100 includes an inner layer circuit board 10 and an outer layer circuit board 20. The inner layer circuit board 10 and the outer layer circuit board 20 are manufactured separately and then pressed together.

S102: Etching the inner layer circuit board 10 to release the copper layer circuit 14.

The inner layer circuit board 10 is etched to release the copper layer circuit 14. The specific steps can be to first coat the copper layer with insulating material according to the pattern of the copper layer circuit 14, and then etch the circuit layer without insulating material, and the circuit layer coated with insulating material is retained and the insulating material is removed to obtain铜层线14。 Copper layer line 14.

S103: Sputtering the inner layer circuit board 10 by plasma.

The copper layer circuit 14 of the inner layer circuit board 10 is sputtered by plasma to roughen the copper layer circuit 14 and increase the contact area of the copper layer circuit 14. The purpose of the roughening treatment of the plasma sputtering copper layer circuit 14 is to increase the roughness of the copper layer circuit 14 to increase the bonding force of the bonding, printing, welding and other processes. The copper after the plasma sputtering copper layer circuit 14 treatment The surface tension of the layer circuit 14 will increase, and the plasma generated by the reactive gas can also increase the surface roughness.

The working principle of plasma sputtering: The electric energy generated by the radio frequency voltage generator forms an electric field between the electrodes. The mixed gas entering the cavity is acted by the electric field and is excited to the plasma to generate free radicals and charged ions. These free radicals and charged ions The ions are mixed with the original gas, and the charged ions and molecules can do physical work through sputtering, and through physical bombardment, the plasma process can complete the surface roughening effect.

Specifically, plasma sputtering the surface of the copper layer circuit 14 to roughen the surface of the copper layer circuit 14.

S104: Perform micro-etching treatment on the inner layer circuit board 10 after sputtering.

The inner layer circuit board 10 after sputtering is subjected to micro-etching treatment. The purpose of the micro-etching is to remove the oxide layer on the surface of the copper layer circuit 14 to clean the surface of the board and form a microscopic roughening to enhance the bonding force of the surface of the board.

Specifically, the surface of the roughened copper layer circuit 14 is micro-etched to form a microscopic roughening.

The further steps of the micro-etching treatment include: A) Put the inner layer circuit board 10 into a micro-etching device and use a micro-etching solution to perform etching. The micro-etching solution includes sulfuric acid, sodium persulfate and copper ions. The concentration of sulfuric acid is controlled between 3%-5%, the content of sodium persulfate is controlled between 50g/L-70g/L, the content of copper ions is controlled less than 25g/L, the reaction temperature is between 28°C and 32°C, and the upper spray The pressure is controlled at 1.3Kg/cm ² -1.7Kg/cm ² , and the downward spray pressure is controlled at 1.1Kg/cm ² -1.5Kg/cm ² .

It is worth noting that the flow rate of the inner layer circuit board 10 in the microetcher will affect the etching rate of the inner layer circuit board 10. In this embodiment, the microetch rate of the inner layer circuit board 10 is 1.5 µm/min to 2.5µm/min.

B) Wash the micro-etched inner circuit board 10 with water.

The inner layer circuit board 10 after microetching is washed with water. In order to ensure the washing effect, it is divided into three steps. The inner layer circuit board 10 is washed with water for the first time, the second time, and the third time.

C) Pickling the inner layer circuit board 10 after washing with water to remove the oxide on the surface of the copper layer circuit 14.

The inner layer circuit board 10 after the step B is put into an acidic solution for pickling to remove oxides and dirt on the surface of the copper layer circuit 14 and improve the conductivity of the copper layer circuit 14.

Sulfuric acid solution can be used for pickling. The concentration of sulfuric acid is controlled between 3% and 5%, the reaction temperature is between 25°C and 35°C, the upper spray pressure is controlled at 1.3 Kg/cm ² -1.7 Kg/cm ² , and the lower spray pressure is controlled at 1.1 Kg/cm ^2- 1.5 Kg/cm ² .

D) Wash the inner circuit board 10 after pickling with water.

Wash the inner layer circuit board 10 after acid washing to remove the residual acid solution. In order to ensure the washing effect, it is divided into three steps. Time washing.

E) Perform anti-oxidation treatment on the inner layer circuit board 10 after washing to remove the pickling liquid on the surface of the inner layer circuit board 10.

The inner layer circuit board 10 after washing with water is subjected to an anti-oxidation treatment to completely remove the acid lotion remaining on the surface of the inner layer circuit board 10 to achieve an anti-oxidation effect.

Use antioxidants for anti-oxidation treatment at room temperature. The concentration of antioxidant is controlled between 0.5%-1.5%, the upper spray pressure is controlled at 1.3 Kg/cm ² -1.7 Kg/cm ² , and the lower spray pressure is controlled at 1.1 Kg/cm ² -1.5 Kg/cm ² .

F) The inner layer circuit board 10 after the anti-oxidation treatment is washed with water.

The inner layer circuit board 10 after the anti-oxidation treatment is washed with water to remove the residual antioxidant solution used in the anti-oxidation treatment process. In order to ensure the washing effect, the inner layer circuit board 10 is washed with water for the first time. , The second washing, the third washing.

G) Drying the inner layer circuit board 10 after washing.

The inner layer circuit board 10 after washing is dried. The function of the drying treatment is to dry the moisture on the inner layer circuit board 10 so that the copper layer circuit 14 will not be oxidized in the air due to water as a medium.

The drying method can be to stand the inner layer circuit board 10 in a dry environment, and the drying method can also use a fan to blow air on the inner layer circuit board 10, and the temperature is controlled at 75°C to 85°C.

S105: pressing the inner layer circuit board 10 after the microetching treatment and the outer layer circuit board to form the LCP substrate 100.

The inner layer circuit board 10 includes a first base layer 12 and copper layer circuits 14 arranged on opposite sides of the first base layer 12. The material of the first base layer 12 may be LCP.

The number of the outer layer circuit boards 20 may be two, and the two outer layer circuit boards 20 are press-fitted and connected to the copper layer circuit 14 respectively. The outer circuit board 20 includes a second base layer 22 and an outer circuit 24, and a side of the second base layer 22 away from the outer circuit 24 is press-fitted and connected to the copper layer circuit 14. The material of the second base layer 22 may be LCP. The pressure bonding of the inner layer circuit board 10 and the outer layer circuit board should be controlled within 24 hours of plasma sputtering to solve the problem of timeliness of plasma sputtering. Because the physical function of plasma sputtering is to reshape and roughen the surface of the material, the protrusions on the surface increase after etching, which increases the surface area. If exposed to contaminated air for too long, mixing of dust, oil, and impurities will cause the surface adhesion after plasma sputtering to gradually decrease. In addition, the chemical action of plasma sputtering introduces oxygen-containing polar groups such as carboxyl and hydroxyl groups. These active molecules are time-sensitive and are prone to chemical changes with other substances.

In the present application, plasma sputtering and micro-etching treatment cooperate with each other to increase the roughness of the copper layer circuit 14. The advantage of this method is that while increasing the roughness of the copper layer circuit 14, no oxide is introduced onto the copper layer circuit 14.

The above are only the embodiments of the present invention. It should be pointed out here that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present invention, but these all belong to the present invention. The scope of protection.

Claims

A manufacturing method of an LCP substrate, characterized in that the manufacturing method of the LCP substrate includes:

Provide inner circuit boards and outer circuit boards;

Etching the inner layer circuit board to release the copper layer circuit;

Sputtering the inner layer circuit board by plasma;

Microetching the inner layer circuit board after sputtering;

The inner layer circuit board after the microetching treatment and the outer layer circuit board are pressed together to form an LCP substrate.
4. The manufacturing method of the LCP substrate according to claim 1, wherein the step of plasma sputtering the inner layer circuit board comprises:

Plasma sputters the surface of the copper layer circuit to roughen the surface of the copper layer circuit.
4. The method of manufacturing an LCP substrate according to claim 1, wherein the step of micro-etching treatment comprises:

Microetching is performed on the surface of the roughened copper layer circuit to form a microscopic roughening.
The manufacturing method of the LCP substrate according to claim 3, wherein the micro-etching is to place the inner circuit board in a micro-etcher, and use a micro-etching solution for etching treatment, and the micro-etching solution includes sulfuric acid, Sodium persulfate and copper ions; the concentration of the sulfuric acid is 3%-5%, the content of sodium persulfate is controlled within 50g/L-70g/L, and the content of copper ions is less than 25g/L.
4. The manufacturing method of the LCP substrate according to claim 3, wherein the step of micro-etching treatment further comprises:

Washing the inner layer circuit board after the microetching;

The inner layer circuit board after washing with water is pickled to remove the oxide on the surface of the copper layer circuit.
5. The LCP substrate manufacturing method according to claim 5, wherein in the pickling step, a sulfuric acid solution with a concentration of 3% to 5% is used for pickling at a temperature of 25°C to 35°C.
5. The manufacturing method of the LCP substrate according to claim 5, wherein the step of micro-etching treatment further comprises:

Water washing the inner layer circuit board after the acid washing;

Anti-oxidation treatment is performed on the inner layer circuit board after water washing to remove the pickling liquid on the surface of the inner layer circuit board.
8. The manufacturing method of the LCP substrate according to claim 7, wherein the anti-oxidation treatment is an anti-oxidation treatment of the inner layer circuit board at room temperature by using an anti-oxidant.
8. The manufacturing method of the LCP substrate according to claim 7, wherein the step of micro-etching treatment further comprises:

Water washing the inner circuit board after the anti-oxidation treatment;

The inner layer circuit board after washing is dried, and the temperature of the drying treatment is 75°C to 85°C.
The manufacturing method of the LCP substrate according to claim 1, wherein in the step of pressing the microetched inner layer circuit board and the outer layer circuit board to form the LCP substrate, the inner layer circuit board is exposed to plasma After the body is sputtered, it is pressed and bonded with the outer layer circuit board within 24 hours.