JPS58218192A - Device for etching printed circuit board and method of etching same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed wiring board etching apparatus and an etching method.

The etching of a conventional printed wiring board will be explained using a double-sided printed wiring board. After performing electroless plating and electroplating on both sides of the printed wiring board (hereinafter referred to as the board) that has copper layers on both sides, in order to provide through holes at desired positions and connect the front and back sides conductively. After a desired printed wiring pattern is formed using a photosensitive resist, that is, an etching resist, through an exposure and development process, an etching chamber with an etching solution stored in the inner bottom and a transport mechanism for transporting the substrate are formed. Then, a desired printed wiring pattern was formed using an etching device having a spray mechanism capable of spraying an etching solution upward and downward in parallel to a transport mechanism that transports the etching chamber.

For this reason, the thickness of the electroplating layer used for conductive connection between the front and back surfaces of the board varies from board to board, and the thickness distribution of the plating layer within a single board varies, making it difficult to form a desired circuit pattern. To do this, several substrates are extracted from each work unit number (hereinafter referred to as a lot), and □ etching is performed on a trial basis using the conveyance speed and spray pressure determined empirically. Next, depending on the circuit finish, circuit width accuracy, and presence or absence of etching on the front and back sides of this board,
i Experimentally, the conveyance speed and spray 1 of the etching device,
:.

Printed wiring board patterns were formed by finely adjusting the pressure to find the optimal etching conditions for each board lot.

Such conventional etching of printed wiring boards has the following drawbacks.

(In response to variations in plating thickness between lots of printed wiring boards, it is necessary to perform punching and trial etching for each lot and repeat until the optimum etching conditions are found. This requires an enormous amount of adjustment man-hours to find the optimum etching conditions.) was needed.

(b) Furthermore, when adjusting the optimal etching conditions, if the plating thickness distribution on the front and back surfaces of the printed wiring board differs,
The circuit finish state, circuit width precision, and etching remaining state on the front and back sides varied greatly, which adversely affected the desired quality and yield.

An object of the present invention is to eliminate such conventional drawbacks and provide an etching apparatus and an etching method thereof.

There it is. i' 11□ According to the present invention, after forming a desired circuit pattern using etching resist or the like, the film thickness and distribution state of the metal layer of the printed wiring board are measured immediately before etching, and the measured electrical signals are used to measure the thickness and distribution of the metal layer on the printed wiring board. Since it has a mechanism to control etching time and spray pressure, it is possible to perform highly accurate and continuous etching.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 41 is a side sectional view of an etching apparatus showing an embodiment of the present invention.

First, the etching mechanism will be explained.

A predetermined amount of etching liquid 2 such as chlorinated steel is placed on the bottom of two etching chambers 1a and 1b arranged on the left and right, and a vibrator 3 is drawn out from the bottom of etching chambers 1a and 1b. Brake pump 4a+4F)+4C+4
A pair of upper and lower spray nozzles 5a+5b are connected parallel to the conveyor 5 in the etching chamber 1a+lb via d.
and 6c+6d, and the etching solution 2 is sprayed. The etching liquid 2 is made to flow through both etching chambers through a joint nozzle 7 which is open and connected to the side wall of the bottom surface on the side where the etching chambers 1a+lb are adjacent, and the etching liquid 2 is balanced.

Next, the conveyance mechanism will be explained.

The conveyor 5, which is connected to the etching chamber 1a+lb and extends left and right, transfers the substrate 8 to the etching chamber 1a+.
, lb, and openings 9a+9b+9G+9d are provided in the shape of windows and pass through in the feeding direction. Further, a metal detector 11 for detecting the conductive layer of the pair of upper and lower substrates 8 is provided in the gap between the rollers at the left end of the conveyor 5, that is, at a position proceeding to the right from the substrate supply section 10. A pair of upper and lower probes 12 for measuring the copper thickness are installed between the rollers at an intermediate position with the opening 9a of the chamber la. This probe 12 is connected to the conveyor 5
The top, bottom, front and back surfaces of the substrate 8 transported by the probe 12
Install it so that it can be adjusted at any height so that it makes contact when passing through.

Next, the control mechanism of the etching sit will be explained.

A control unit 13 that starts upon receiving an electric signal from the metal detector 11
is installed in the upper part outside the etching chamber 1a, and this control unit 1
A copper thickness measuring device 14 connected to the etching chamber 1 and measuring the copper thickness via the probe 12 in response to a signal from the control section 13 is installed in the upper part of the etching chamber 1, a, in the same way as the control section 13. Also,
The fljlJ control section 13 has a circuit that performs arithmetic processing according to the copper thickness sent as an electric signal from the copper thickness measuring device 14, and links the drive motor 15 of the conveyor 5 and the spray bottle 7''4a+4b+4c+4d. A magnetic circuit for operation is provided to form a control mechanism, and a printed wiring board etching apparatus according to the present invention having the control mechanism and the etching mechanism and transport mechanism described above.

Next, a method of etching the substrate of the present invention will be explained.

The front and back surfaces of a copper-clad substrate having through holes at predetermined positions are subjected to non-removal plating and 1C plating to make a conductive connection, and then an exposure and development process is performed using a photosensitive resist, that is, an etching resist. After forming the desired stamp wiring pattern, the substrate 8 is conveyed onto the rollers of the substrate supply section 10 of the conveyor 5 of the etching apparatus according to the present invention. When the substrate 8 passes between the metal thinners 11, an electric signal is sent to the control section 13, which starts the control section 13 and operates the copper thickness measuring instrument 14. Next, the substrate 8 transported to the probe 12 is continuously measured by the probe 12 for the distribution state of copper thickness. The measurement signal is input to the copper thickness measuring device 14 and is processed by the control unit 13 according to the copper thickness sent from the copper thickness measuring device 14 as an electrical signal.

The control unit 13 calculates the average value l of the copper thickness based on the distribution state of the copper thickness of the board 8 sent from the copper thickness measurement 514. For double-sided boards, the average copper thickness on each side is 11.1. are calculated individually, and further averaged to obtain (il, +12 /
:? ) is calculated, and this value is taken as the average value l of the copper thickness distribution of the double-sided board.

For single-sided plates, the average value of the copper thickness of the single-sided plate l! is used as the average value l of the copper thickness distribution. In this way, in order to average the copper thickness distribution, the control section 13 is provided with a circuit that stores the optimum spray pressure and etching time for various copper thicknesses assumed in advance. board 8
The etching time (T
> and spray pressure (the target setting program obtained the results shown in the graph of Figure 2).

Furthermore, the conveyor speed (V) is the etching time ('l'p), the number of etching chambers in operation (in), (
(2 chambers in this example) and the length of the etching chamber [existence]
), it can be calculated from the formula v-n L / 'l'p, so multiplying this implementation sequence by n = 11
If ft is 2tL=180crIL+, then FIG. 2 can be developed into a program as shown in FIG. 3.

Depending on the distribution of copper thickness, spray pumps 4a+4b+4c l 4d are added to the etching chamber 1a+lb.
are operated individually, and the number n of etching chambers is automatically selected as 1 or 2. Also, along with this, the upper and lower spray pressures are Pl, p2. P3 and conveyor speed V are arbitrarily determined.

As described above, the following effects can be obtained by the present invention.

(1) There is no need to automatically detect the copper thickness distribution state of the printed wiring board and perform sampling and trial etching for each lot to accommodate variations in plating thickness between lots of printed wiring boards to find the optimal etching conditions. There is no need for any adjustment man-hours to find etching conditions.

(11) Furthermore, since the optimal etching conditions are constantly monitored, the circuit finish V-shape, circuit width accuracy, and remaining etching condition on the front and back surfaces of the printed wiring board are maintained uniformly, significantly improving quality and yield. It can be improved.

[Brief explanation of drawings]

The following shows the setting program for the spray pressure, number of etching chambers, and conveyor speed. la+lb...Etching room, 2...
Etching liquid, 3...Pipe, 4a+4b+4
C+4d・・・Spray pump, 5・・・・・・
Conveyor, 6a+6b. 6C+6d...Spray nozzle, 7...
・Joint pipe, 8...Printed arrangement, [board (
board), 9aI9bI9c+9d...opening,
10... Substrate supply unit, 11... Gold aphrodisiac, 12... Probe (for measuring copper thickness),
13... Control unit, 14... Copper thickness measuring device, l5... Drive motor. Leopard 2 Illustration 3 Eyebrow (M/ka)

Claims (2)

[Claims] (1) Store the etching at the inner bottom, ()II
+ One or more etching chambers with openings on the left and right sides of the wall, a processing plate conveyance mechanism extending through the etching chamber, and one or more etching chambers above and below the conveyance mechanism in the etching chamber in parallel with the conveyance mechanism. A spray mechanism for etching liquid is provided, and a pair of upper and lower metal fittings and a metal film thickness are provided sequentially at a predetermined interval in the direction of movement from the supply position of the plate to be processed outside the etching chamber. What is claimed is: 1. An etching apparatus for a printed wiring board, comprising: a measurement section; and a control section that controls the conveyance mechanism and the spray mechanism in conjunction with each other based on a drowsiness signal issued from the metal detection section and the metal film thickness measurement section. (2) a step of continuously measuring the film thickness distribution state of the metal layer after forming an etching resist film having a desired circuit pattern on at least one surface of the printed wiring board having the metal layer; The method includes a step of etching the metal layer by controlling the etching time and spray pressure according to variations in the thickness of the metal layer using a transport mechanism and a spray mechanism that are controlled in conjunction with electrical signals obtained by continuous measurement. A distinctive method of etching printed wiring boards.