Agitated wet process machine
An agitated wet process machine comprises a delivery system and many jets. The delivery system comprises a delivery belt and many rollers, wherein the rollers on the upper side or the lower side of the delivery belt are used to deliver workpieces. Many blades are added on each of the rollers to agitate a chemical solution. The jets above and below the delivery belt are used to spray or supply the chemical solution to the workpieces.
The present application is based on, and claims priority from, Taiwan Application Serial Number 95109941, filed Mar. 22, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety.
BACKGROUND1. Field of Invention
The present invention relates to a machine for wet process. More particularly, the present invention relates to an agitated wet process machine.
2. Description of Related Art
Because of the rapid development in high technology and an increased demand for light and easy to use products, light, thin, small and portable electronic products are becoming the most popular products. Because electronic products are getting smaller, the internal volume of electronic products containing printed the circuit boards is also getting smaller. Therefore, there is a need to develop high-density printed circuit boards containing more circuits in a smaller area.
Line widths and line spaces on general printed circuit boards are about 4-6 mil. (1 mil.=0.025 nm). On high-density printed circuit boards, line widths and line spaces are about 1 mil. Because the line widths and the line spaces on high-density printed circuit boards are narrower than those on general printed circuit boards, the process quality requirement for high-density printed circuit boards is stricter than that for general printed circuit boards.
In the printed circuit wet processes, both the developing process and the etching process are important for the line widths and the line spaces of printed circuit boards. However, there is a serious water-retention problem, which limits recent manufacturing processes to manufacture high-density printed circuit boards which have narrower line widths and line spaces than general printed circuit boards.
SUMMARYIt is therefore an aspect of the present invention to provide an agitated wet process machine, which can eliminate the problem of water-retention in the wet process and thus increase the quality of wet processes, including the developing and etching processes.
In accordance with the foregoing and other aspects of the present invention, an agitated wet process machine is provided. The agitated wet process machine comprises a delivery system and many jets. The delivery system comprises a delivery belt, many rollers and many blades. The rollers are located on the upper side or the lower side of the delivery belt to deliver workpieces on the delivery belt. The blades are on each roller to agitate a chemical solution. The jets are located above and below the delivery belt and are used to spray or supply the chemical solution to the workpieces.
In accordance with the foregoing and other aspects of the present invention, an agitated wet process machine is provided. The agitated wet process machine comprises a delivery system and many jets. The delivery system comprises a delivery belt, many rollers and many blades. The rollers are located on the upper side or the lower side of the delivery belt to deliver workpieces on the delivery belt. The blades are on each roller to agitate a chemical solution. There is a distance between the blades and fringes of the rollers. The jets are located above and below the delivery belt and are used to spray or supply the chemical solution to the workpieces.
In accordance with the foregoing and other aspects of the present invention, a process employing the agitated wet process machine is provided. Firstly, many workpieces below many jets are delivered. Then, a chemical solution is sprayed to the workpieces to process them. Finally, the chemical solution is agitated to increase the processing efficiency.
In conclusion, the invention adds blades on the rollers in the traditional wet process machine. When the roller rotates, the blades on the rollers can bring a fresh chemical solution into the processing region and bring the processed chemical solution out of the processing region. The blades on the rollers thus can increase the mobility of the chemical solution. The chemical solution no longer accumulates around the rollers. Therefore, the invention not only solves the problem of water-retention but also increases the quality and the efficiency of the wet process. The number of the blades, the shape of the blades, the distance between the blades and fringes of the rollers and the position of the jets in the invention all can be adjusted to meet any special requirements for different processes. Moreover, the invention not only can be employed in the developing and etching processes of printed circuit boards to increase the manufacturing precision but can also be employed in other chemical processes which have requirements to increase the process precision.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
In the following, the manufacturing process of printed circuit boards is used as an example to illustrate the concept of the invention. However, the invention is not limited to the process of printed circuit boards. In reality, because of the development and progress of high technology, a wet process is employed from the traditional industry of printed circuit boards to fields of other industries. Now, wet processes are successfully employed in the industries of semiconductor, liquid crystal display panel and plasma display. Therefore, the invention can be employed in these industries to increase their process quality.
The manufacturing processes of printed circuit boards can be divided into three types, mechanical process, wet process and image transfer process. Among these processes, the wet process is the process that uses chemical solutions. Wet processes comprise electroplating, developing, etching, film stripping, washing, degreasing, cleaning with ultrasonic, de-smearing and chemical roughing etc. Among these processes, the developing and etching processes have critical influence on line widths and line spaces of printed circuit boards. The invention not only increases the quality of the developing and etching processes to manufacture high-density printed circuit boards but can also improve the quality of other wet process-related manufacturing processes.
In the processes of printed circuit boards, a layer of either positive or negative photoresist is initially formed on the copper films of the substrate. A predefined pattern is transferred to the photoresist by a light-exposing process. Then, the exposed region of the positive photoresist or the unexposed region of the negative photoresist is dissolved in a developing solution during a developing process. The copper uncovered by the photoresist is etched in an etching process to form circuits on the substrate. Finally, the photoresist is removed by a film stripping process.
Among the above processes, the developing and etching processes are critical in the manufacturing printed circuit boards. Good developing and etching processes can correctly transfer each subtle feature of a predefined circuit pattern to copper films of a substrate to from circuits. Therefore, some printed circuit boards such as high-density printed circuit boards, which have higher and stricter demands for line widths and line spaces, often need good developing and etching technologies.
However, there is a serious water-retention problem in recent wet processes. This problem affects the quality of the etching and developing processes and limits the line widths and the line spaces from becoming narrower to satisfy the requirement of high-density printed circuit boards.
In the following, a diagram will be used to illustrate the water-retention problem.
In
In the traditional machine in
In the following, a mass transfer formula will be used to illustrate the influence of the rollers on the flow of the chemical solution. The chemical solution agitated by the blades of the rollers can be viewed as an open channel flow. The mass transfer formula of the chemical solution is expressed in the following:
In Eq. (1)-(4), kc is a mass transfer coefficient; De is an equal diameter; DAB is a diffusion coefficient; ub is an average flow rate; ρ is a liquid density; μ is a liquid viscous coefficient. When the rollers rotate, the blades on the rollers will agitate the chemical solution to increase the axial flow rate of the chemical solution. Based on Eq. (2) and Eq. (3), an increase of the average flow rate (ub) will result in an increase of the Reynolds number and Sherwood number. Therefore, the mass transfer coefficient (kc) increases.
NA=kc(CA∞−CA*) Eq. (5)
In Eq. (5), NA is a mass transfer value; CA∞ is the concentration of the liquid in the bulk phase; CA* is the concentration of the liquid at the processed surfaces of workpieces. Eq. (5) indicates that an increase in the mass transfer coefficient (kc) will result in an increase of the mass transfer value (NA). Therefore, the effective ingredients of the chemical solution can reach the processed surfaces of the workpieces easily and thus the processing efficiency of the chemical solution increases.
In conclusion, the agitated wet process machine of the invention adds blades on the rollers to increase the mass transfer of the chemical solution. Moreover, four design parameters can be adjusted to achieve an optimum wet process quality. Therefore, printed circuit boards processed by the agitated machine has narrower line widths and line spaces and the agitated machine can be used to process high-density printed circuit boards. The following are the four design parameters that can be adjusted.
(1) The agitated wet process machine of the invention can selectively install jets with large angles, low pressures and high flow volumes above the rollers.
(2) The number of the blades on each of the rollers can be changed.
(3) The shape of the blades on the rollers can be changed.
(4) The distance between the blades and fringes of the rollers can be changed.
Accordingly, the present invention has the following advantages.
(1) The agitated wet process machine of the invention can eliminate the wet process water-retention problem and thus increase the wet process quality, including the developing and etching processes. Therefore, the agitated machine can be used to process high-density printed circuit boards.
(2) The agitated wet process machine of the invention can increase the processing efficiency of the chemical solution.
The preferred embodiments of the present invention described above should not be regarded as limitations to the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. The scope of the present invention is as defined in the appended claims.
Claims
1. An agitated wet process machine, comprising:
- A delivery system, comprising: a delivery belt; and a plurality of rollers located on the upper side or the lower side of the delivery belt to deliver workpieces on the delivery belt; and a plurality of blades on each of the rollers to agitate a chemical solution; and
- a pluraility of jets located above and below the delivery belt and used to spray or supply the chemical solution to the workpieces.
2. The machine of claim 1, wherein the number of the blades on each of the roller is six.
3. The machine of claim 1, wherein the surface of the blades is flat.
4. The machine of claim 1, wherein the surface of the blades is curved.
5. The machine of claim 1, wherein there is a distance between the blades and fringes of the rollers.
6. The machine of claim 1, wherein the jets are located between the rollers.
7. The machine of claim 6, wherein the jets are located above the rollers.
8. An agitated wet process machine, comprising:
- A delivery system, comprising: a delivery belt; and a plurality of rollers located on the upper side or the lower side of the delivery belt to deliver workpieces on the delivery belt; and a plurality of blades on each of the rollers to agitate a chemical solution, wherein there is a distance between the blades and fringes of the rollers; and
- a pluraility of jets located above and below the delivery belt and used to spray or supply the chemical solution to the workpieces.
9. The machine of claim 8, wherein the jets are located between the rollers.
10. A process employing the machine of claim 1, comprising:
- delivering a plurality of workpieces below a plurality of jets;
- spaying a chemical solution on the workpieces to process the workpieces; and
- agitating the chemical solution to increase the processing efficiency.
Type: Application
Filed: Oct 20, 2006
Publication Date: Sep 27, 2007
Inventor: Shih-Chang Chang (Tao Yuan)
Application Number: 11/583,820
International Classification: C23F 1/00 (20060101);