TWI539876B - Etching method and etching device - Google Patents

Description

Etching method and etching device

The present invention relates to an etching method and an etching apparatus, and more particularly to an etching method and an etching apparatus for patterning a processed conductive layer on a substrate to form a wiring portion in a process of manufacturing a printed wiring board.

In the etching method of forming a wiring portion having a fine pattern on the surface of a printed wiring board (substrate) for mounting a component such as a semiconductor, a method of ejecting an etching liquid onto a substrate by a one-fluid nozzle is widely used. A resist film as a mask layer is formed in advance on the copper foil, and the etching liquid contacts the copper foil which is not protected by the resist film, whereby the copper foil is patterned.

However, in the method of using the one-fluid nozzle, in the processing of the fine-grained wiring pattern in which the etching droplets have a large particle diameter, for example, the interval between adjacent wiring portions is 50 μm or less, the etching droplets cannot be etched. Etching is performed in the pattern of the upper resist film, and it is difficult to increase the E/F (etch factor).

In order to solve the problem of the above-described unfavorable situation, a method of using a 2-fluid nozzle which sprays an etchant and a compressed air has been proposed. By using a two-fluid nozzle, it is possible to perform a smaller droplet of the etching liquid than the one-fluid nozzle, and the ejection speed is also increased. For example, even in the etching in which the pattern has been miniaturized to 50 μm or less, the fine droplets of the etching liquid are pushed into the pattern at a high speed to raise the E/F.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-256458

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-287881

However, in the method using the two-fluid nozzle, since a large amount of compressed air is consumed, the equipment is enlarged or the cost is increased.

Accordingly, an object of the present invention is to provide an etching method and an etching apparatus which can obtain an appropriate E/F while suppressing the consumption of compressed air to a minimum.

In order to achieve the above object, the etching method of the first aspect of the present invention includes the first etching of the etching target surface by ejecting the etching liquid from the one fluid nozzle and etching the etching target surface. An etching process is performed, and a second etching process in which an etching liquid is mixed with a gas and ejected by a two-fluid nozzle to etch the etching target surface to be etched in the first etching process to further etch the surface to be etched. In the second etching process, the etching liquid having a smaller droplet than the first etching process is blown onto the etching target surface with a stronger impact force than the first etching process.

An etching apparatus according to a first aspect of the present invention includes a conveying means, a one-fluid nozzle, and a two-fluid nozzle. The means of transport is passed along the order (1) The etching target portion and the predetermined transport path of the second etching processing unit transport the object to be etched. The first fluid processing unit is disposed in the first etching processing unit, and the etching liquid is ejected onto the etching target surface of the etching target object conveyed by the conveying means. The second fluid processing unit is disposed in the second etching processing unit, and the etching target surface of the etching target object conveyed by the first etching processing unit by the conveying means is mixed and sprayed with the etching liquid and the gas to be blown. The 2 fluid nozzle is an etchant that has a smaller droplet than the one fluid nozzle, and is blown onto the etching target surface with a stronger impact force than the one fluid nozzle.

In the above method and apparatus, on the surface side of the layer to be etched, first, a rough etching treatment by a large etching liquid from a nozzle of the first fluid nozzle is performed. Then, a fine etching treatment by the etching liquid from the small droplets of the two-fluid nozzle is performed, and even if the wiring pattern is miniaturized, the etching liquid can be pressed into the resist film on the layer to be etched. Inside the pattern. As described above, since the two-fluid nozzle is not used in all the etching processes, and the one-fluid nozzle and the two-fluid nozzle are effectively used in combination, it is possible to obtain an appropriate E/F while suppressing the consumption of compressed air to a minimum. Here, E/F means the ratio of the etching depth (thickness of the layer to be etched) to the amount of lateral etching (undercut) of the layer to be etched, and the larger the value, the more suitable.

An etching method according to a second aspect of the present invention is the etching method according to the first aspect, wherein the etching target surface is an upper surface of the etching target, and the first etching process includes: suctioning the surface of the etching target by the one fluid nozzle. The first attraction project for removing the etching liquid. Further, the second etching process includes: sucking an etching liquid that is blown onto the surface of the etching target by the two-fluid nozzle In addition to the second attraction project.

In the etching apparatus according to the second aspect of the present invention, the etching apparatus according to the first aspect includes the suction means disposed in both of the first etching processing unit and the second etching processing unit. In the conveyance means, the object to be etched is conveyed in a substantially horizontal direction while the etching target surface is facing upward. The suction means picks up the etching liquid which is blown on the etching target surface by the 1 fluid nozzle and the 2 fluid nozzle, respectively.

In the above method and apparatus, the etching liquid to be blown by the one-fluid nozzle and the two-fluid nozzle is removed from the etching target surface at an early stage. Therefore, it is possible to prevent the occurrence of the etchant which can hinder the blowing of the etching liquid from occurring, and to perform etching with high in-plane uniformity.

Further, in the etching method or the etching apparatus according to the second aspect, the amount of the etching liquid applied to the etching target surface by the two-fluid nozzle is the total blowing amount of the etching liquid on the etching target surface by the one-fluid nozzle and the two-fluid nozzle. The ratio of the amount of 2% or more and 50% or less is suitable.

According to the present invention, an appropriate E/F can be obtained while suppressing the consumption of compressed air to a minimum.

Hereinafter, an embodiment of the present invention will be described based on the drawings.

First, an outline of a method of manufacturing a printed wiring board to which the etching method and the etching apparatus of the present embodiment are applied will be described with reference to the cross-sectional view of Fig. 2 .

As shown in Fig. 2 (a), for example, a copper foil is formed on both surfaces of an insulating substrate (etching target) 1 made of a thermosetting resin such as an epoxy resin or another resin or the like, in a film thickness of several tens of micrometers. The same conductive layer (etched layer) 2. The method of forming the conductive layer 2 may be any method such as adhesion, plating, vapor phase growth, or the like, and both surfaces of the substrate 1 serve as an etching target surface.

Next, as shown in FIG. 2(b), a resist film 3 is formed on the upper layer of the conductive layer 2 by photolithography (dry film resist or liquid resist, etc.), and pattern exposure and development processing are performed. This forms the resist film 3 in the upper layer of the conductive layer 2. The formation process of the resist film 3 is performed on both surfaces of the substrate 1.

Next, as shown in FIG. 2(c), the conductive layer 2 on both surfaces of the substrate 1 is subjected to an etching treatment using the resist film 3 as a mask. That is, the conductive layer 2 is etched in accordance with the pattern of the resist film 3, and the wiring portion 2a is patterned.

After the wiring portion 2a is patterned, the resist film 3 is peeled off by, for example, a strong alkali solution or an organic solvent treatment. Thereby, a desired printed wiring board is formed.

The etching treatment of the conductive layer 2 having the resist film 3 as a mask is performed by using the etching apparatus and method of the present embodiment. Fig. 1 is a schematic configuration view showing an etching apparatus of the embodiment.

In the etching processing chamber 11 of the etching apparatus 10, a transport path that extends horizontally linearly from the inlet 14 on one side (the left side in FIG. 1) toward the outlet 15 on the other side (the right side in FIG. 1) is set. A plurality of transport rollers (transport means) 16 are provided in the path. Transfer roller 16 will be patterned The substrate 1 on which the resist film 3 is formed is held in a substantially horizontal shape with one surface facing upward and the other surface facing downward, and is transported along the transport path.

The upper portion in the etching processing chamber 11 is roughly divided into a first etching processing unit 12 that performs a first etching process and a second etching processing unit 13 that performs a second etching process, and the transport path sequentially passes through the inlet 14 side. 1 etching processing unit 12 and second etching processing unit 13 on the outlet 15 side. A plurality of one-fluid nozzles 20 are disposed in the first etching processing unit 12, and a plurality of two-fluid nozzles 30 are disposed in the second etching processing unit 13. The first fluid nozzles 20 and the two fluid nozzles 30 are movable relative to each other. Fixed (still), or it can be oscillated.

An etching liquid 5 based on copper chloride, ferric chloride or an alkaline substance is stored in the bottom portion of the etching processing chamber 11 below the transport path. Each of the first fluid nozzles 20 is connected to a first etching liquid supply line 21 for supplying the etching liquid 5 stored in the etching processing chamber 11. The first pump 22, the filter 24, and the pressure gauge 23 are provided in the first etching liquid supply line 21, and the etching liquid 5 in the etching processing chamber 11 is filtered by the first pump 22 through the filter 24. It is supplied to each of the fluid nozzles 20 at a predetermined pressure. The supply pressure to the etching liquid of the one-fluid nozzle 20 is measured by the pressure gauge 23.

A second etching liquid supply line 31 for supplying the etching liquid 5 stored in the etching processing chamber 11 is connected to each of the two fluid nozzles 30. The second pump 32, the filter 34, and the pressure gauge 33 are provided in the second etching liquid supply line 31, and the etching liquid 5 in the etching processing chamber 11 is filtered by the second pump 32 through the filter 34. Is supplied to each of the two fluid nozzles 30 at a predetermined pressure . The supply pressure of the etching liquid to the two-fluid nozzle 30 is measured by the pressure gauge 33. However, the second pump 32 and the filter 34 may not be used for the supply of the two fluid nozzles 30, and the first pump 22 and the filter 24 may be shared.

Further, an air supply line 40 for supplying compressed air (pressurized air) generated by the gas supply source 41 is connected to each of the two fluid nozzles 30. An air filter 42, a flow meter 43, and a pressure gauge 44 are provided in the air supply line 40. The gas supply source 41 is a fan, a compressor, a blower, or the like. The air supply amount to the two-fluid nozzle 30 is measured by the flow meter 43, and the air supply pressure is measured by the pressure gauge 44.

The fluid nozzle 20 is sprayed to the substrate 1 by spraying an etchant. On the other hand, the two-fluid nozzle 30 mixes and etches an etching liquid supplied from a different path and air (pressurized air), and etches a liquid droplet smaller than the one fluid nozzle 20 by a ratio of 1 The fluid nozzle 20 is blown to the substrate 1 with a stronger impact force.

The fluid nozzle 20 and the two fluid nozzles 30 are disposed above and below the transport path, respectively. The upper and lower first fluid nozzles 20 eject the etching liquid onto the upper surface and the lower surface of the substrate 1 transported by the transfer drum 16 and are then blown. Further, the upper and lower two-fluid nozzles 30 are used to mix and spray the etching liquid and the air on the upper surface and the lower surface of the substrate 1 conveyed by the transfer drum 16, and to perform the blowing.

A plurality of suction units (suction means) 50 are disposed above the transport path of the first and second etching processing units 12 and 13, and the upper one fluid nozzle 20 and the two fluid nozzles 30 are respectively attached to the substrate. The upper etching liquid of 1 is attracted and removed. Each attraction unit 50 is: a suction pipe (not shown) that extends substantially horizontally in a direction substantially perpendicular to the conveyance path, and is formed on the outer circumferential surface of the suction pipe (in the present embodiment, the lower surface) A plurality of slit-like suction nozzles (not shown) that form an opening toward the transport path, and the suction nozzles are disposed between the blowing regions of the etching liquid jetted by the one-fluid nozzle 20 and the two fluid nozzles 30, respectively. In the field of configuration, the desired attraction is produced.

Each of the suction ducts is connected to the suction port 52a of the emitter 52 provided on the way of the circulation line 54 through the suction line 51. Both ends of the circulation line 54 communicate with the inside of the etching processing chamber 11, and a circulation pump 53 is provided in the middle to be a closed circuit. The circulation pump 53 picks up the etching liquid 5 in the etching processing chamber 11, and is formed in a state where the pressure is applied to the emitter 52, and is returned to the etching processing chamber 11 again. The etchant circulating in the circulation line 54 passes through the ejector 52, and the suction port 52a of the ejector 52 is formed into a negative pressure, so that the etchant liquid blown on the upper surface of the substrate 1 passes through the suction pipe through the suction nozzle. 51 is attracted.

When the etching process is performed by using the etching apparatus 10 described above, on the surface side of the substrate 1 (conductive layer 2), the etching liquid which is large by the droplets from the one-fluid nozzle 20 is performed in the first etching processing unit 12 A rough etching process. Next, in the second etching processing unit 13, a detailed etching process by the etching liquid of the fine droplets from the two-fluid nozzle 30 is performed. Therefore, even in the processing of the miniaturized wiring pattern, the etching droplets can be pressed into the pattern of the resist film 3 on the conductive layer 2.

As shown above, the 2-fluid nozzle 30 is not used in all etching processes, Since the one-fluid nozzle 20 and the two-fluid nozzle 30 are used effectively, it is possible to obtain an appropriate E/F while suppressing the consumption of compressed air to a minimum.

Further, the etching liquid to which the first fluid nozzle 20 and the two fluid nozzles 30 are blown is removed from the upper surface of the substrate 1 at an early stage, so that the etchant which can hinder the blowing of the etching liquid can be prevented from being stopped in advance, and It is possible to perform etching with high in-plane uniformity.

Next, an etching test performed using the etching apparatus 1 described above will be described.

In the etching test, the ratio of the amount of the etching liquid to the etching target surface by the two-fluid nozzle 30 to the total amount of the etching liquid of the etching liquid on the etching target surface by the one fluid nozzle 20 and the two fluid nozzles 30 is measured. The amount of pressurized air used (L/min) and E/F (etching factor) when changed to 0%, 2%, 5%, 11%, 23%, 43%, and 100%. E/F refers to the ratio of the etching depth (thickness of the layer to be etched) to the amount of lateral etching (undercut amount) of the layer to be etched, and the larger the value, the more suitable.

The following two types of pattern formation are performed on the etching target surface. In the sample 1, a printed wiring board of 18 μm copper foil was patterned in L/S=20/20 μm, and in the sample 2, a printed wiring board of 35 μm copper foil was patterned in L/S=50/50 μm. form. As shown in Fig. 2(c), L is a wide pattern of the wiring pattern (wiring portion 2a) under the resist film 3, and S is a wiring pattern of the lower layer of each of the adjacent resist films 3 (adjacent wiring) The distance between the patterns). In the case of a pattern of L/S=20/20 μm, the distance between the width of the wiring pattern and the adjacent wiring pattern is 20 μm.

The etching conditions of the sample 1 and the sample 2 were such that the etching liquid pressure in the one-fluid nozzle 20 was set to 0.2 MPa, and the etching liquid pressure and the air pressure in the two-fluid nozzle 30 were both set to 0.3 MPa.

The results of the experiment were carried out by changing the ratio of the number of one-fluid nozzles to the number of two-fluid nozzles, and the E/F system is shown in FIGS. 3 and 4. It is understood that the E/F is increased when the amount of the liquid to be used in the two-fluid nozzle 30 is increased with respect to the total amount of liquid that is ejected to the printed wiring board until the pattern is formed (see FIGS. 3 and 4). However, when the amount of the liquid to be ejected from the two-fluid nozzle 30 is equal to or greater than a certain amount, a large change in E/F is lost. When the amount of pressurized air is used, the amount of blowing from the two-fluid nozzle 30 is relatively derived. The ratio of the total amount of blowing of the fluid nozzles 20 and the two fluid nozzles 30 (the ratio of the amount of etching liquid using the two-fluid nozzle 30) is preferably 50% or less. If the ratio of the amount of etching liquid from the two-fluid nozzle 30 exceeds 50%, the pressurized air must be 15,000 L/min or more. When using a generally used oil-free screw compressor (Oil-Free Screw Compressor) to supply 0.3 MPa of pressurized air at 15,000 L/min or more, the compressor must have a plurality of stages, so it is more appropriate to use the amount below this amount. . Further, considering the increase in E/F, it is understood that the ratio of the amount of etching liquid used in the two-fluid nozzle 30 is preferably 2% or more. As described above, the ratio of the amount of blowing from the two-fluid nozzle 30 to the total amount of blowing from the one-fluid nozzle 20 and the two-fluid nozzle 30 is preferably 2% or more and 50% or less.

The present invention has been described above with reference to the embodiments, and the present invention is not limited thereto, and may be appropriately modified without departing from the scope of the invention.

For example, in the above embodiment, an example in which etching treatment is performed in one etching processing chamber 11 is shown. However, etching processing may be performed by a plurality of etching processing chambers in succession. In this case, there may be an etching processing chamber in which only the upstream side of the first etching processing portion is provided or an etching processing chamber in which only the downstream side of the second etching processing portion is provided.

1‧‧‧Substrate (etching object)

2‧‧‧ Conductive layer (etched layer)

2a‧‧‧Wiring Department

3‧‧‧Resistive film

5‧‧‧etching solution

10‧‧‧ etching device

11‧‧‧etching chamber

12‧‧‧1st etching processing unit

13‧‧‧2nd etching processing unit

14‧‧‧ Entrance

15‧‧‧Export

16‧‧‧Transport roller (transport means)

20‧‧1 fluid nozzle

21‧‧‧1st etching liquid supply line

22‧‧‧First pump

23‧‧‧ Pressure gauge

24‧‧‧Filter

30‧‧‧2 fluid nozzle

31‧‧‧Second etchant supply line

32‧‧‧2nd pump

33‧‧‧ pressure gauge

34‧‧‧Filter

40‧‧‧Air supply line

41‧‧‧ gas supply source

42‧‧‧Air filter

43‧‧‧ Flowmeter

44‧‧‧ pressure gauge

50‧‧‧Attraction unit (attraction means)

51‧‧‧Attraction line

52‧‧‧Injector

52a‧‧‧ attracting mouth

53‧‧‧Circulating pump

54‧‧‧Circulation line

Fig. 1 is a schematic block diagram showing an etching apparatus according to an embodiment of the present invention.

2 is an enlarged cross-sectional view showing a printed wiring board for etching treatment, wherein (a) shows a state before the etching process, and (b) shows an ideal state after the etching process.

Figure 3 is a table showing the results of the etching test.

Figure 4 is a graph showing the results of an etching test.

1‧‧‧Substrate (etching object)

5‧‧‧etching solution

10‧‧‧ etching device

11‧‧‧etching chamber

12‧‧‧1st etching processing unit

13‧‧‧2nd etching processing unit

14‧‧‧ Entrance

15‧‧‧Export

16‧‧‧Transport roller (transport means)

20‧‧1 fluid nozzle

21‧‧‧1st etching liquid supply line

22‧‧‧First pump

23‧‧‧ Pressure gauge

24‧‧‧Filter

30‧‧‧2 fluid nozzle

31‧‧‧Second etchant supply line

32‧‧‧2nd pump

33‧‧‧ pressure gauge

34‧‧‧Filter

40‧‧‧Air supply line

41‧‧‧ gas supply source

42‧‧‧Air filter

43‧‧‧ Flowmeter

44‧‧‧ pressure gauge

50‧‧‧Attraction unit (attraction means)

51‧‧‧Attraction line

52‧‧‧Injector

52a‧‧‧ attracting mouth

53‧‧‧Circulating pump

54‧‧‧Circulation line

Claims (4)

An etching method comprising: a first etching process for etching an etching target surface by ejecting an etching liquid by a one-fluid nozzle, and etching the etching target surface; and etching the liquid The second etching process in which the gas is mixed and ejected by the two-fluid nozzle, and the etching liquid is etched on the etching target surface etched in the first etching process, and the etching target surface is further etched in the first etching In the second etching process, the etching liquid having substantially the same etching rate is sprayed onto the etching target surface by the one-fluid nozzle and the two-fluid nozzle, and the second etching process is higher than the foregoing In the first etching process, the etching liquid of the fine droplets is blown onto the etching target surface with a stronger impact force than the first etching process, and the amount of the etching liquid applied to the etching target surface by the two fluid nozzles is The ratio of the total amount of the etching liquid to the etching target surface of the first fluid nozzle and the two fluid nozzles is 2% or more and 50% or less, and the etching target surface is the aforementioned Engraved object, the first etching engineering comprising: a suction removal to a first fluid suction nozzle 1 by the aforementioned construction is blown onto the etch target surface etchant. In the etching method of the first aspect of the invention, the second etching process includes: a second suction project that sucks and removes an etching liquid that is blown onto the etching target surface by the two fluid nozzles. An etch apparatus that transports an object to be etched through a predetermined transport path of the first etch processing unit and the second etch processing unit in sequence, and is disposed in the first etching processing unit, and a first fluid nozzle that ejects an etching liquid onto an etching target surface of an object to be etched by the transporting means, and is disposed in the second etching processing unit, and is provided by the transporting means by the first a second fluid nozzle in which the etching target surface of the etching target to be transported by the etching processing unit is mixed, and the first etching means disposed in the first etching processing unit is in the first In the etching processing unit and the second etching processing unit, an etching liquid having substantially the same etching rate is attached to the etching target surface by the one-fluid nozzle and the two-fluid nozzle, and the two-fluid nozzle system is to be compared. The etchant for the fine droplets of the first fluid nozzle is blown onto the etching target surface by a stronger impact force than the first fluid nozzle, and the two fluid nozzles are used to The ratio of the amount of the etchant to be etched on the target surface is 2% or more and 50% or less with respect to the total amount of the etchant of the etchant surface of the first fluid nozzle and the two fluid nozzles, and the transfer means is The etching target is conveyed in a substantially horizontal direction while the etching target is facing upward, and the first suction means sucks and removes the etching liquid which is blown onto the etching target surface by the one fluid nozzle. Such as the etching device of claim 3, wherein The second suction means is disposed in the second etching processing unit, and the second suction means sucks and removes the etching liquid which is blown onto the etching target surface by the two fluid nozzles.