JPH036888A - Method of cleaning board for printed wiring board - Google Patents

Abstract

PURPOSE:To remove the remnants of minute through-holes properly by jetting cleaning liquid to the cleaning surface of a board and forming a liquid film on this, and then jetting high pressure air intermittently from above the liquid film. CONSTITUTION:By carrying the board for printed wiring board after boring processing into a liquid film process part 1 through a transfer roller 13 and ejecting pressurized cleaning liquid from ejection nozzles 80 and 81, a liquid film of cleaning liquid is formed at the cleaning face of the board for printed wiring board. After that, the board is carried into a high pressure gas ejecting process part 2 through a transfer roller 14, and it passes under an ejection nozzle 30 while being guided by transfer rollers 22 and 23 and guide rollers 50 and 51. At this time, high pressure gas is ejected intermittently from the ejection port 35 of the ejection nozzle 30, and the high pressure gas is injected into each through hole from above the liquid film formed at the cleaning face, whereby the cleaning liquid passes each through-hole together with high pressure gas, and as a result, the remnants in each through-hole can be removed without being left.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of cleaning a substrate for a printed wiring board.

[Conventional technology]

Conventionally, due to the structure of a printed wiring board, conduction between both surfaces and multiple layers in a double-sided or multilayer printed wiring board is configured through through holes.

However, as the density of printed wiring circuits increases, the through holes are also miniaturized, for example, micro through holes of 0.2φ or less are formed, and these micro through holes are irregularly shaped according to the design of the printed wiring circuit. The holes are arranged in

Further, in the formation of such a printed wiring board, drilling of minute through-holes is carried out by a cleaning process using a cleaning liquid in order to remove the residue afterwards.

The cleaning process for the through-holes of the printed wiring board substrate is performed during the conveyance process of the printed wiring board substrate in conjunction with other processing steps required in the printed wiring board manufacturing process. This is carried out by draining a cleaning liquid from above the printed wiring board substrate being transferred in a cleaning process after the processing process.

[Problem to be solved by the invention]

However, the current state of the art is that the conventional cleaning process for through-holes in printed wiring board substrates cannot cope with the miniaturization of through-holes due to the increased density of printed wiring circuits, as described above. It is.

In other words, even if the cleaning solution flows out from the top of the printed wiring board substrate during the subsequent transportation process, the through holes may be mixed with large diameter through holes and small through holes, or many small through holes may be scattered. In this case, the cleaning liquid will flow out into the large-diameter through-hole, and a liquid film of cleaning liquid will form on the opening of the tiny through-hole due to the action of surface tension on the tiny through-hole. This results in the product passing through the first cleaning process without removing the residue, which poses a major problem in post-processing and the generation of defective products.

Therefore, the present invention was developed in view of the drawbacks in the method for cleaning through holes in printed wiring board substrates, and it is an object of the present invention to provide a cleaning method that can accurately remove the residue of minute through holes. This is the purpose.

[Means and effects for solving the problems] The present invention, when cleaning the through holes of a printed wiring board substrate, sprays a cleaning liquid onto the cleaning surface of the substrate to form a liquid film thereon, and then Intermittently (pulse-like) high-pressure gas is applied from above the liquid film.
It cleans by spraying on the water.

Therefore, by effectively utilizing the fact that a liquid film of the cleaning liquid is formed on the cleaning surface of the substrate due to surface tension, high-pressure gas is intermittently injected from above the liquid film that is uniformly formed over the entire cleaning surface. By doing so, the cleaning liquid can be passed through each through-hole, and the residue in the through-hole can be accurately removed regardless of the diameter of each through-hole.

〔Example〕

Examples of the method of the present invention will be described in detail below, together with the cleaning equipment used directly in carrying out the method.

FIG. 1 is a side sectional view of the cleaning device, FIG. 2 is a front view with a part of the high-pressure gas jetting process section omitted, and FIG. 3 is a side view of the same.

In the figure, 10 indicates a cleaning device, and this cleaning device 10
As shown in FIG. 1, a conveyance line for conveying a printed wiring board substrate (not shown) as a member to be cleaned is installed between the lengthwise direction of the frame 12 installed on the upper side of the base plate 11. side(
The structure is constructed by arranging a conveyance roller 13 and a pair of upper and lower conveyance rollers 14 between the monthly conveyance section side (indicated by the arrow on the left side of Fig. 1), and the liquid film process is carried out from the conveyance section side along the conveyance line. Part 1, high pressure gas jetting process part 2,
It is constructed by providing a washing process section 3 and a water absorption process section 4 for cleaning liquid and washing liquid.

The liquid film process section 1 has cleaning liquid jet nozzles 80 and 81 installed above the conveyance roller 13, and cleaning liquid supply tanks 82 and 83 connected to the re-spray nozzles 80 and 81 via control valves (not shown). It is constructed by connecting to.

In addition, the supply tanks 82 and 83 are connected to a cleaning liquid filtration tank 89 provided below the high-pressure gas jetting process section 2, and the cleaning liquid recovered in the liquid film process section 1 is transferred to the filtration tank 89.
9 and supplied to the jet nozzles 80 and 81 via the supply tanks 82 and 83.

The high-pressure gas jetting process section 2 is constructed by arranging high-pressure gas jetting nozzles 90 and 91 between the conveyance rollers 14.

Therefore, the high pressure gas jetting nozzles 90 and 91 have the same configuration, and the details of the configuration will be explained in the second section below.
This will be explained with reference to FIG.

First, the jet nozzle 30 is secured to the lower side of both nozzle bodies 33 and 34 by clamping the nozzle bodies 33 and 34, which are divided into two in the length direction, with clamp fittings 39 at required intervals in the length direction. A slit-shaped high-pressure gas jet hole 35 (slit width, for example, 0.21 to 0.2 m + m) is provided that opens between the nozzle bodies 33 and 34 in the length direction, and the upper sides of both nozzle bodies 33 and 34 communicate with the slit-shaped high-pressure gas jet hole 35. At least, a plurality of slot coaters 36 are installed between the slot coaters 36 in the length direction.

Further, each slot coater 36 is configured to be able to supply high-pressure gas through a communication port 37 with a high-pressure gas supply source (not shown) while being controlled by a control valve (not shown).

For example, by electrically controlling a control valve by applying a pulse wave, high-pressure gas can be intermittently ejected from the ejection hole 35.

Further, by holding each slot coater 36 by a support frame 31, the jet nozzle 30 is installed above the conveyance line so as to be vertically adjustable, and the support frame 31 is attached to the frame body 11 in the longitudinal direction (Fig. 2). The support frame 31 is installed so that it can reciprocate in both left and right directions), and one of the left and right sides of the support frame 31 is connected to a connecting arm (not shown) with a reciprocating motion of 1ff (not shown). Support frame 3
By reciprocating the jet nozzle 1, the jet nozzle 30 can be reciprocated in the length direction.

Further, below the jet nozzle 30, a cleaning surface of a printed wiring board substrate as a member to be cleaned and a jet nozzle 30 are provided.
Guide rollers 50 and 51 are rotatably arranged in parallel so that the distance between the jet holes 35 can be maintained constant at all times (for example, maintaining a distance of about one garden between the cleaning surface and the jet holes 35). A connecting gear 56 is attached to each of the rotating shafts 54 of 51 and 51, and the connecting gear 55 attached to the drive shaft 53 is engaged with the connecting gear 56, whereby the guide rollers 50 and 51 are rotated through the drive of the drive shaft 53. Furthermore, O-rings 52 are stretched between both guide rollers 50 and 51 at required intervals in the length direction.

In the second and third times, 22 and 23 are conveyance rollers, 57 is a bearing of the rotating shaft 54 of the guide rollers 50 and 51, and 58 is a bearing of the drive shaft 53, respectively.

Next, the washing process section 3 is operated as shown in FIG.
It is constructed by installing jet nozzles 84 and 85 on both the upper and lower sides of 4, respectively, for spouting water for washing.

Further, each of the jet nozzles 84 and 85 is connected to a water supply tA (not shown) via a control valve (not shown).

Further, the water absorption process section 4 is configured by arranging water absorbent wrinkle rollers 86 and 87 between the conveyance rollers 14 in parallel.

Further, each of the wrinkle rollers 86 and 87 is configured to be rotatable via a drive section 88.

The configuration of the cleaning device 10 described above is not limited to the above-mentioned configurations, but can be implemented with other configurations that are sufficient to achieve the object of the present invention. Although the case has been described in which the ejection nozzles 90 and 91 having the configuration shown in the figure are provided in parallel, it is possible to obtain the desired effect with only one ejection nozzle 9°.

Now, a method for cleaning printed wiring board substrates using the cleaning apparatus 10 having the above configuration will be described below.

First, the printed wiring board substrate after drilling is carried into the liquid film process section l via the conveyance roller 13, and pressure (for example, 15 kg/cm2 to 150 kg/ct) is applied.
The sprayed cleaning liquid is ejected from jet nozzles 8o and 81 to form a liquid film of the cleaning liquid on the cleaning surface of the printed wiring board substrate.

Incidentally, the cleaning liquid is carried out using a cleaning liquid having an appropriate composition containing water as a main component.

Therefore, when a film is formed on the cleaning surface in the liquid film process section 1, the presence of a large number of minute through-holes causes surface tension to work even more, making it easier to form a liquid film on the cleaning surface.

Thereafter, the substrate after the liquid film process is carried into the high-pressure gas jetting process section 2 via the conveyance roller 14, and is conveyed by conveyance rollers 22 and 23 and guide rollers 50 and 51 as shown in the second and third figures. It passes under the jet nozzle 30 while being guided, but at this time, the jet nozzle 3
High-pressure gas is ejected intermittently (pulse-like) from the ejection hole 35 of No. 0, and the high-pressure gas is injected into each through-hole over a liquid film formed on the cleaning surface, so that the cleaning liquid along with the high-pressure gas is sprayed into each through hole. As a result of penetrating through the through hole,
It can be removed without leaving any residue in each through hole.

Further, the jetting nozzle 90 is reciprocated in a direction perpendicular to the direction of conveyance of the substrate, and can uniformly jet high-pressure gas corresponding to differences in the arrangement state of each through hole and the diameter of the through hole. It is.

Therefore, depending on the diameter of each through-hole formed in the board, cleaning can be done using the conventional method by high-pressure spraying of cleaning liquid in the previous process, but in the case of minute through-holes, due to the effect of surface tension, A liquid film of the cleaning liquid will be formed.

Therefore, by intermittently spraying high-pressure gas through the jet nozzle 30 onto the cleaning surface on which such a liquid film is formed, cleaning of minute through holes can be accurately performed. It is.

Although the case has been described in which the cleaning is carried out with a gap of about 1 mm between the jet nozzle 30 and the cleaning surface, it is possible to carry out the cleaning while adjusting this gap as necessary.

That is, the support frame 31 is attached to the frame body 11 by a method such as adjusting the height position via an adjusting means (not shown).

After the cleaning surface of the substrate is processed in the high-pressure gas jetting process section 2, the substrate is further carried into the water washing process section 4 via the conveyance roller 14, and both the front and back surfaces of the substrate are passed through the jetting nozzle 84.
The substrate is then washed with water sprayed from 85 to remove any residue adhering to the front and back surfaces of the substrate.

After that, the substrate is further carried into the water absorption process section 4 via the conveyance roller 14, and the water adhering to the substrate is absorbed and removed by the wrinkle rollers 86 and 87, and then the substrate is conveyed to the carry-out section and subjected to the required cleaning. Processing is completed.

[Effects of the Invention] As is clear from the above description, according to the method of the present invention, through-holes in printed wiring board substrates can be cleaned without being affected by the size of the through-hole diameter or the arrangement state of the through-holes. , can be carried out appropriately.

Further, the method of the present invention can be applied to cleaning holes in other porous members with the same effects as those for through holes in printed wiring board substrates.

[Brief explanation of drawings]

The drawings show a cleaning device that is used directly to carry out the method of the present invention, and FIG. 1 is a side sectional view of the cleaning device, FIG. 2 is a front view with a part of the high-pressure gas jetting process section omitted, and FIG. 3 is the same. FIG. 1...Liquid film process section 2...High pressure gas ejection process section 3...Water washing process section 4...Water absorption process section 10...Cleaning device 11...Base plate 12...Frame body 13 .14,22.23...Conveyance roller 30...
Spout nozzle 31...Support frame 33.34...Nozzle body 35...Blowout hole 36...Thront coater 7...Connection port 9...Clamp fitting 0.51...Guide roller 2 ... O-ring 3.54 ... Rotating shaft 5.56 ... Gear 7.58 ... Bearing 0.81 ... Spray nozzle 2.83 ... Supply tank 4.85 ... Spray Nozzle 6.87...Shibori roller 8...Drive motor 9...Filtration tank 0.91...Ejection nozzle Patent applicant Furnace Co., Ltd. 482-

Claims (6)

[Claims] (1) A method for cleaning a printed wiring board substrate having a large number of through holes, which includes a liquid film forming step of forming a liquid film of a cleaning liquid on the surface to be cleaned of the substrate, and a liquid film forming step on the surface to be cleaned after the liquid film is formed. A method for cleaning a printed wiring board substrate, characterized in that the through-hole is cleaned in a high-pressure gas injection step of injecting high-pressure gas. (2) The method for cleaning a printed wiring board substrate according to claim 1, wherein the high-pressure gas injection step includes intermittently injecting the high-pressure gas. (3) The printed wiring board according to claim 1, wherein the high-pressure gas jetting step comprises jetting the high-pressure gas through a jetting nozzle that reciprocates back and forth in a direction perpendicular to the direction in which the surface to be cleaned is transported. How to clean the board. (4) In the injection process of the high pressure gas, the atmospheric pressure is 15 kg/c.
2. The method for cleaning a printed wiring board substrate according to claim 1, wherein the gas is ejected in a range of m^2 to 150 kg/cm^2. (5) The method for cleaning a printed wiring board substrate according to claim 1, wherein the liquid film forming step involves flowing or spraying a cleaning liquid containing water as a main component. (6) In the liquid film process, the cleaning liquid is applied to the surface to be cleaned at a liquid pressure of 15%.
2. The method of cleaning a printed wiring board substrate according to claim 1, wherein the cleaning liquid is sprayed at a pressure in the range of kg/cm^2 to 150 kg/cm^2.