JP2017160514A - Etching method and etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently suppress side etching in a tenting process.SOLUTION: An etching method is provided, in which an etching solution is sprayed to an etching target coated with an etching resist having a predetermined pattern so as to etch a part of the etching target exposed through an opening of the etching resist. The etching solution comprises a solution essentially comprising cupric chloride and/or ferric chloride with addition of an additive for forming an etching suppression coating film. Spraying of the etching solution is performed by mixing the etching solution with a gas and ejecting the mixture from a two-fluid nozzle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an etching method and an etching apparatus used for manufacturing a printed wiring board.

  In recent years, with the miniaturization of electronic devices and the high density mounting of components, the fine pitch of circuit patterns has progressed in printed wiring boards. One of the methods for forming such fine pitch pattern circuit layers is a tenn. Ting is known. Tenting is a circuit pattern in which an insulating layer or a conductive layer provided on an insulating substrate is covered with an etching resist that is open except for the pattern portion, and the conductive layer portion exposed from the opening of the etching resist is removed by etching. Is a method of forming a circuit layer having

  Patent Document 1 discloses an etching solution and a gas in order to suppress side etching in which a conductor layer is etched in a horizontal direction wider than the opening width of an etching resist when a circuit layer having a fine pitch pattern is formed by tenting. Are mixed and ejected from a two-fluid nozzle to form fine droplets, and the fine droplets are sprayed into the opening of the etching resist to prevent the etching liquid from staying on the conductor layer portion in front of the opening. An etching method is disclosed.

JP 2002-256458 A

  However, although the technique described in Patent Document 1 has the effect of suppressing side etching relatively by preventing the etching liquid from staying on the conductor layer portion in front of the opening of the etching resist, it does not reduce the side etching itself. However, side etching cannot be sufficiently suppressed.

  An object of this invention is to provide the etching method and etching apparatus which can fully suppress the side etching at the time of tenting.

The etching method of the present invention comprises:
In an etching method in which an etching solution is sprayed on an etching target covered with an etching resist having a predetermined pattern, and the portion of the etching target exposed from the opening of the etching resist is etched.
The etching solution comprises an additive for forming an etching suppression film in a solution mainly composed of cupric chloride and / or ferric chloride,
The etching solution is sprayed by mixing the etching solution and gas and ejecting the mixture from a two-fluid nozzle.

  In the etching method of the present invention, the additive for forming the etching suppression film is preferably a triazole compound.

  In the etching method of the present invention, the object to be etched is preferably a conductor layer, more preferably a copper layer.

  In the etching method of this invention, Preferably, the etching liquid after the said spraying is attracted | sucked from the upper surface of the said etching target object.

The etching apparatus of the present invention is
In an apparatus for spraying an etching solution to an etching target coated with an etching resist having a predetermined pattern and etching a portion of the etching target exposed from the opening of the etching resist,
The etching solution comprises an additive for forming an etching suppression film in a solution mainly composed of cupric chloride and / or ferric chloride,
A two-fluid nozzle that mixes the etching solution with a gas and blows the etching solution against the object to be etched is provided.

  In the etching apparatus of the present invention, the additive for forming the etching suppression film is preferably a triazole compound.

  In the etching apparatus of the present invention, the object to be etched is preferably a conductor layer, more preferably a copper layer.

  In the etching apparatus of this invention, Preferably, the suction apparatus which attracts | sucks the etching liquid after the said spraying from the upper surface of the said etching target object is included.

It is sectional drawing which shows one Embodiment of the etching apparatus of this invention used for implementation of one Embodiment of the etching method of this invention.

  FIG. 1 is a cross-sectional view showing an embodiment of an etching apparatus of the present invention used for carrying out an embodiment of an etching method of the present invention. The etching apparatus of this embodiment etches a substrate material M, for example. Thus, it can be used when manufacturing a printed wiring board. Here, for the substrate material M, for example, an insulating layer made of an epoxy resin or the like, or a conductive layer as an etching object made of a copper layer or the like is provided on one side or both sides of an insulating substrate, and the conductive layer is made of dry film resist (DFR). And the etching resist is opened by removing the pattern portion by photolithography or the like, and the etching apparatus of this embodiment etches the conductor portion of the conductor layer exposed from the opening of the etching resist. By removing, that is, by tenting, a circuit layer having a conductor circuit pattern is formed on one or both surfaces of the interlayer insulating layer or the insulating substrate. Then, in another process after the formation of this circuit layer, a desired printed wiring board is formed by removing the etching resist with a solvent or the like, or further covering the circuit layer with a solder resist having an open bump. .

  In order to perform such etching, the etching apparatus of this embodiment indicated by reference numeral 1 in the drawing includes a substrate material provided in the etching chamber 2 by a plurality of transfer rollers 3 from an inlet 2a at one end to an outlet 2b at the other end. The transport path of M is set to be substantially horizontal, and the substrate material M held approximately horizontally by the transport roller 3 is transported along the transport path from the left to the right in the drawing as indicated by an arrow. The

  In the upper part of the etching chamber 2, a plurality of two-fluid nozzles 4 are arranged on the upper and lower sides of the transfer path so as to face the transfer path. It may be fixed to the substrate, or may be swung in a direction orthogonal to the conveying direction of the substrate material M.

  An etching solution 5 is stored in the lower part of the etching processing chamber 2. The etching solution 5 is sent to the etching solution supply line 9 through the filter 7 and the flow meter 8 by the pump 6 connected to the bottom of the etching process chamber 2, and each of the two fluids is supplied by the etching solution supply line 9. It is pumped to the nozzle 4. The pressure of the etchant 5 in the etchant supply line 9 is measured by a pressure gauge 10 and maintained at a predetermined pressure by manual or automatic operation of the valve 11 between the pump 6 and the filter 7.

  The etching solution 5 used here is an additive that forms a film having an etching-inhibiting effect in a solution mainly containing cupric chloride and / or ferric chloride, which has been used as an etching solution. For example, a triazole-based compound is added at a high concentration, and a surfactant is further added. As a specific composition of such an etching solution, for example, the applicant of the present application has proposed in WO2005 / 086551A1 International Publication Things are known.

  The etching apparatus 1 of this embodiment is also provided with a compressor 12, and compressed air generated by the compressor 12 is sent to a compressed air supply line 15 via an air filter 13 and a flow meter 14. The compressed fluid is supplied to each two-fluid nozzle 4 by a compressed air supply line 15. The pressure of the compressed air in the pipe line between the air filter 13 and the flow meter 14 is measured by the pressure gauge 16 and is determined by manual or automatic operation of the valve 17 between the air filter 13 and the flow meter 14. Maintained at pressure.

  And in the etching method of the said embodiment using the etching apparatus 1 of this embodiment, the board | substrate material M hold | maintained substantially horizontal with the conveyance roller 3 along the conveyance path | route set in the etching process chamber 2 is shown. When the substrate material M is conveyed on the both sides of the substrate material M during conveyance of the substrate material M, it is positioned above and below the conveyance path. When the conductor layer is provided only on the upper surface of the substrate material M from each of the two fluid nozzles 4, the etching solution 5 is sprayed toward the substrate material M from each of the two fluid nozzles 4 positioned on the transport path. Is done.

  At this time, since the compressed air is supplied to each of the two-fluid nozzles 4 together with the etching solution 5, the etching solution 5 is mixed with the compressed air in each of the two-fluid nozzles 4 so that the speed is higher than that of the normal one-fluid nozzle. Thus, the fine liquid droplets are ejected from each of the two fluid nozzles 4 and reach the substrate material M with a strong spray hitting force. Thereby, even when the opening of the etching resist is narrow in order to form a circuit layer having a fine pitch pattern, the etching solution 5 enters the opening vigorously, and cupric chloride and / or ferric chloride in the etching solution 5 is obtained. In the etching solution 5, the additive composed of, for example, a triazole compound is removed laterally from the front of the opening and hidden behind the etching resist. An etching-inhibiting film is formed on the wall surface of the conductor layer to suppress side etching, and the surfactant in the etching solution 5 promotes circulation of the etching solution 5 in the opening to efficiently expose the conductor layer portion exposed to the front of the opening. To etch.

  Therefore, according to the etching method of this embodiment using the etching apparatus 1 of this embodiment, side etching is sufficiently suppressed even when the opening of the etching resist is narrow to form a circuit layer having a fine pitch pattern. A circuit layer having a circuit pattern can be formed by efficiently etching the conductor layer.

  Further, in the etching apparatus 1 of this embodiment, the upper portion of the etching processing chamber 2 is adjacent to the downstream side in the transport direction of the substrate material M with respect to each of the two fluid nozzles 4 above the transport path. Suction heads 18 are provided so as to extend over the entire width, and each suction head 18 is connected to an ejector 20 by an etchant suction line 19, and the ejector 20 is connected to a lower part of the etching chamber 2 in a circulation path 21. Along with the pump 22 in the middle, the pump 22 sucks the etching solution 5 in the etching processing chamber 2 into the circulation path 21 and supplies it to the ejector 20 to form a jet of the etching solution in the ejector 20. The inside of each suction head 18 becomes a negative pressure through the suction pipe 19, and the etching liquid 5 remaining on the substrate material M is removed from each suction head 18. Feeding the ejector 20 to pull removed, it returns with jet from the pump 22 to the etching chamber 2.

  And in the etching method of this embodiment using the etching apparatus 1 of this embodiment, it is ejected from each of the two fluid nozzles 4 during the etching of the substrate material M and onto the surface of the etching resist of the substrate material M or in the opening. The remaining etching solution 5 is sucked and removed by the negative pressure from the ejector 20 by the suction head 18 adjacent to the downstream side of each of the two-fluid nozzles 4. Etching does not proceed excessively to the side, and side etching can be sufficiently suppressed in this respect.

  As described above, based on the illustrated example, the etching method and the etching apparatus of the present invention are not limited to this example, and can be appropriately changed within the scope of the claims. Further, the air may be supplied not from the compressor 12 provided in the etching apparatus 1 but from an air pipe or the like in the factory.

DESCRIPTION OF SYMBOLS 1 Etching apparatus 2 Etching process chamber 2a Inlet 2b Outlet 3 Conveying roller 4 2 Fluid nozzle 5 Etching liquid 6, 22 Pump 7 Filter 8, 14 Flow meter 9 Etching liquid supply line 10, 16 Pressure gauge 11, 17 Valve 12 Compressor 13 Air filter 15 Compressed air supply line 18 Suction head 19 Etching liquid suction line 20 Ejector 21 Circulation path M Substrate material

Claims (10)

In an etching method in which an etching solution is sprayed on an etching target covered with an etching resist having a predetermined pattern, and the portion of the etching target exposed from the opening of the etching resist is etched.
The etching solution comprises an additive for forming an etching suppression film in a solution mainly composed of cupric chloride and / or ferric chloride,
The etching solution is sprayed by mixing the etching solution and gas and ejecting the mixture from a two-fluid nozzle.   2. The etching method according to claim 1, wherein the additive forming the etching suppression film is a triazole compound.   3. The etching method according to claim 1, wherein the etching object is a conductor layer.   4. The etching method according to claim 3, wherein the conductor layer is a copper layer.   5. The etching method according to claim 1, comprising sucking the sprayed etchant from an upper surface of the object to be etched. 6. In an etching apparatus for spraying an etchant on an etching target covered with an etching resist having a predetermined pattern and etching a portion of the etching target exposed from the opening of the etching resist,
The etching solution comprises an additive for forming an etching suppression film in a solution mainly composed of cupric chloride and / or ferric chloride,
A two-fluid nozzle for spraying the etching liquid on the object to be etched by mixing the gas with the gas is provided.   7. The etching apparatus according to claim 6, wherein the additive for forming the etching suppression film is a triazole compound.   8. The etching apparatus according to claim 6, wherein the object to be etched is a conductor layer.   9. The etching apparatus according to claim 8, wherein the conductor layer is a copper layer.   10. The etching apparatus according to claim 6, further comprising a suction head that sucks the sprayed etchant from an upper surface of the object to be etched.

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