JP2010147263A - Method of manufacturing microstructure and method of manufacturing circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique for stably manufacturing a microstructure using a mold. <P>SOLUTION: The microstructure is manufactured by preparing an organic resin layer of the mold having a three-dimensional microstructure on a surface, forming a metal layer which completely buries the three-dimensional microstructure and forms a common support portion on a surface of the organic resin layer and forming a bond via metal oxide on an interface between the organic resin layer and metal layer, exposing the organic resin layer to a formic acid gas and reducing the metal oxide on the interface with the metal layer with formic acid penetrating the organic resin layer to cut the bond between the metal layer and organic resin layer, peeling the metal layer having the bond cut from the organic resin layer, pressing the metal layer peeled from the organic resin layer into the organic resin layer which is softened, and removing the common support portion of the metal layer above the organic resin layer through chemimechanical polishing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microstructure and a circuit board manufacturing method, and more particularly to a microstructure and a circuit board manufacturing method including a peeling process.

  MOS transistors, which are constituent elements of semiconductor integrated circuits, have been miniaturized year by year. With the miniaturization of MOS transistors, the wiring has also been miniaturized, and a wiring pitch on the submicron level has already been put into practical use.

  Lithography is used in the process of creating a miniaturized pattern. In photolithography, an image of a reticle or mask is exposed on a photosensitive resist film and developed to form a resist pattern, which is used for selective processing of a base. Since the resist pattern is created through a resist film formation, exposure, and development process for each processing process, a highly accurate resist pattern is expensive. In electron beam lithography, an electron beam beam is used instead of a light beam, and an electron beam resist film is used instead of a photosensitive resist film. Although electron beam lithography can achieve high resolution, the cost of the process further increases.

  US Pat. No. 5,772,905 proposes a technique for transferring a mold having a desired pattern to a resist film instead of exposing the resist film with light or an electron beam. A mold having a raised pattern corresponding to the groove and hole to be formed is prepared. The mold is pressed against a resist film such as PMMA, the resist film is heated to a glass transition temperature of 105 ° C. or higher, for example, 200 ° C., and pressure is applied to the mold to transfer the raised pattern of the mold to the resist film. Grooves and holes corresponding to the raised pattern of the mold are formed in the resist film. After the temperature of the resist film is lowered and the mold is removed, the residue of the resist film in the grooves and holes is removed by ashing with oxygen plasma.

  In this manner, a resist pattern having a desired shape is created by pressing a mold having a three-dimensional structure against the resist film. This technique is a new technique that can be called mechanical lithography, and it can be expected to reduce the cost by repeatedly using the mold.

It is desired to reduce the wiring pitch of a package wiring board (circuit board) on which a semiconductor integrated circuit device is mounted. The wiring board is usually provided with a copper wiring pattern on an insulating substrate. A subtracting method in which a resist pattern having a wiring pattern is formed on a copper film formed on the entire surface of an insulating substrate and an unnecessary portion of the copper film is removed by etching is used up to a minimum line width of about 35 μm. In the semi-additive method that can form finer wiring, a thin copper seed layer is formed on an insulating substrate by sputtering or electroless plating, a resist pattern having an opening of the wiring pattern is formed thereon, and the exposed seed layer A copper film is plated on the substrate, the resist pattern is removed, and the exposed copper seed layer is removed by etching to leave a wiring pattern. It is used for forming a wiring pattern having a minimum line width of about 10 μm.

An imprint method has recently been proposed as a method for forming finer wiring (for example, Patent Document 2). A metal plate (also called a stamper) having wiring-shaped protrusions is prepared, and the protrusion pattern (male type) of the stamper is transferred as a groove pattern (female type) to the organic resin film on the insulating substrate. A copper film is plated on the organic resin film, and unnecessary portions on the organic resin film are removed by chemical mechanical polishing (CMP) or the like to leave a wiring pattern.
JP, 2005-5721, A The present inventor pushes a metal structure which has a wiring-shaped protruding pattern on a support part into an insulating organic resin film, and then removes a support part by CMP etc. in an insulating organic resin film. Proposed an implant method that leaves a wiring pattern such as copper and aluminum.

  Imprinting a mold into an organic resin film or implanting a metal structure is a new technology and has many possibilities. However, this technology has not been established yet. In particular, how to stably manufacture a fine structure has not been solved.

  One object of the present invention is to provide a technique capable of stably producing a microstructure.

According to one aspect of the present invention,
Preparing an organic resin layer of a mold having a three-dimensional microstructure on the surface;
On the surface of the organic resin layer, a metal layer that completely embeds the three-dimensional microstructure and forms a common support portion is formed, and a bond through a metal oxide is bonded to the interface between the organic resin layer and the metal layer. Forming, and
Exposing the organic resin layer to formic acid gas, reducing the metal oxide at the interface with the metal layer with formic acid permeating the organic resin layer, and cutting the bond between the metal layer and the organic resin layer; ,
A method for producing a microstructure comprising

According to another aspect of the invention,
Preparing a master metal layer having a three-dimensional microstructure on the surface;
An organic resin layer that completely embeds the three-dimensional microstructure and forms a common support portion is applied and cured on the surface of the metal layer, and a metal oxide is interposed at the interface between the metal layer and the organic resin layer. Forming a bond;
Exposing the organic resin layer to formic acid gas, reducing the metal oxide at the interface with the metal layer with formic acid permeating the organic resin layer, and cutting the bond between the metal layer and the organic resin layer; ,
A method for producing a microstructure comprising

  Release properties can be obtained by reducing the metal oxide at the interface between the organic resin layer and the metal layer. Since no release agent is used, the dimensional accuracy can be improved.

  The inventor has made various attempts to manufacture a fine wiring pattern for implants having a wiring pattern with a wiring width of 0.5 μm to 0.9 μm and less than a micron order on a support substrate. A metal layer is embedded in an organic resin layer having a groove having a width of the order of micron or less corresponding to the wiring pattern, and then the metal layer is peeled from the organic resin layer to form a metal layer having a three-dimensional wiring pattern on the common support layer. Various methods were discussed. In general, it is known that adhesion between a metal and an organic material is mainly due to a chemical bond in which a metal oxide is interposed. When embedding a metal layer in an organic resin layer having a groove, in order to peel off the metal layer, a release agent having a release action is applied thinly on the surface of the organic resin layer so that the metal layer adheres to the organic resin layer. Inhibits and obtains releasability. If the coating thickness of the release agent is uneven, the dimensional accuracy of the microstructure is degraded. If the release agent is leaked, it is difficult to peel off the metal layer.

  Hereinafter, embodiments will be described with reference to the drawings.

  1A to 1H are cross-sectional views illustrating a method for producing a metal structure and a wiring board according to Example 1. FIG.

  As shown in FIG. 1A, a female mold 11 made of an organic resin such as polymethyl methacrylate (PMMA) is prepared. The female mold 11 has, for example, grooves 12 corresponding to the wiring pattern shape to be created. Hereinafter, a case where a copper structure for implanting a copper wiring is formed by plating will be described as an example.

  As shown in FIG. 1B, a copper seed layer 14 is formed on the surface of the female mold 11 by sputtering. A copper layer 15 is plated on the copper seed layer 14 by electrolytic plating. The copper layer 15 is of a thickness that forms a common support layer sufficient to backfill the grooves 12 and provide physical support. The copper layer 15 embedded in the organic resin mold 11 exhibits adhesion by forming a metal oxide 16 at the interface.

  As shown in FIG. 1C, the female mold 11 on which the copper layer 15 is formed is introduced into a hermetically sealed gas phase processing chamber 17 and a formic acid gas 18 is supplied. Formic acid (HCOOH) is an organic acid with a strong pungent odor and has a boiling point of about 101 ° C. at normal pressure. The temperature of the mold 11 is set to a temperature of 150 ° C. to 200 ° C., for example. The concentration of formic acid gas is, for example, 0.1% to several percent. The formic acid gas is a gas having high permeability to the organic resin, easily penetrates into the organic resin at a temperature of 150 ° C. to 200 ° C., reaches the interface between the organic resin mold 11 and the copper layer 15, and becomes a metal oxide. 16 is reduced.

  As shown in FIG. 1D, when the metal oxide 16 at the interface disappears, the organic resin mold 11 and the copper layer 15 are easily peeled off.

  As shown in FIG. 1E, the copper layer 15 having a fine structure can be peeled from the organic resin mold 11 by pulling up the copper layer 15. The copper layer 15 having a fine structure is easily damaged.

  As shown in FIG. 1F, the copper layer 15 formed with a fine structure can be protected by storing and transporting the copper layer 15 in a state of being accommodated in the organic resin mold 11 without peeling. By using the organic resin layer as a cap, it is possible to suppress oxidation of the copper layer and prevent deformation of the fine structure.

  As shown in FIG. 1G, an insulating organic resin film 20 such as an epoxy resin sheet is formed on an insulating substrate 19 such as a glass epoxy substrate, and the organic resin film 20 is heated and softened to form a fine wiring pattern. Push in layer 15. As the epoxy resin sheet, for example, ABFGX-13 manufactured by Ajinomoto Co., Inc. is used. An annealing process or the like is performed as necessary to cure the organic resin layer 20. Thereafter, the temperature of the substrate is lowered.

  As shown in FIG. 1H, the copper layer 15 is subjected to chemical mechanical polishing (CMP) from the surface, the common support portion is removed, and the insulating organic resin layer 20 is exposed. A circuit board having the fine wiring 15x embedded in the insulating organic resin layer is obtained.

  Note that the portion to be removed by CMP is formed for physical support and is not used as a wiring. You may form with the other metal which has a physical support function. Although the case where the wiring pattern is formed using copper as the metal has been described, the metal structure to be created is not limited to the wiring. A MEMS (mechanical electrical micro structure) having a fine structure of a micron order or less can also be created. In addition to copper, a copper alloy, nickel, a nickel alloy, tin, a tin alloy, zinc, a zinc alloy, or the like may be used as a metal that forms a chemical bond via oxygen with an organic resin.

  Although the case where the metal material layer is deposited by plating has been described, sputtering, vapor deposition, CVD, or the like may be used instead of plating. After forming the metal layer, CMP may be performed as necessary to flatten the surface of the common support portion. Although the case where the seed layer is formed by sputtering has been described, the seed layer may be formed by electroless plating. The formic acid treatment can be performed at a temperature of 150 ° C. or less, but the treatment time becomes longer. The female type organic resin mold can be produced by pushing a male metal master into the organic resin film and peeling it.

  2A to 2G are cross-sectional views illustrating a method for producing a female resin mold using a metal master according to Example 2. FIG.

  As shown in FIG. 2A, a metal master 21 made of a metal having excellent durability such as Ni or Ni alloy is prepared. The metal master 21 has a protruding structure 22 corresponding to the wiring pattern shape to be created, for example. The metal master 21 is formed, for example, by etching a silicon or quartz substrate by a photolithographic process to create a reverse pattern master and transferring the irregularities formed on the master onto a nickel plating layer or the like. Since the master is used repeatedly, it is preferably made of nickel or a nickel alloy having excellent durability.

  As shown in FIG. 2B, a liquid organic resin layer 22p is applied to the surface of the metal master 21, and the solvent is evaporated. The organic resin is thermosetting or UV (ultraviolet) curable.

  As shown in FIG. 2C, the organic resin layer 22p is heated or irradiated with UV to form a cured organic resin layer 22. The organic resin layer 22 exhibits adhesion by forming the metal oxide 16 at the interface with the metal master 21.

  As shown in FIG. 2D, the metal master 21 on which the organic resin layer 22 is formed is introduced into the sealed gas phase processing chamber 17 and formic acid gas 18 is supplied. The temperature of the metal master 21 and the organic resin layer 22 is set to a temperature of 150 ° C. to 200 ° C., for example. The concentration of formic acid gas is, for example, 0.1% to several percent. The formic acid gas easily penetrates into the organic resin layer 22 at a temperature of 150 ° C. to 200 ° C., reaches the interface between the organic resin layer 22 and the metal master 21, and reduces the metal oxide 16.

  As shown in FIG. 2E, when the metal oxide 16 at the interface disappears, the organic resin layer 22 and the metal master 21 are easily peeled off.

  As shown in FIG. 2F, the organic resin layer 22 can be peeled from the metal master 21 by pulling up. The organic resin layer 22 having a fine structure is easily damaged.

  As shown in FIG. 2G, the organic resin layer 22 formed with a fine structure can be protected by storing and transporting the organic resin layer 22 in a state of being fitted to the metal master 21.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. The fine structure is not limited to wiring, but may be any fine structure having a three-dimensional structure.

When, 1A to 1H are cross-sectional views illustrating a method for producing a metal structure and a wiring board according to Example 1. FIG. When, 2A to 2G are cross-sectional views illustrating a method for producing a female resin mold according to Example 2. FIG.

Explanation of symbols

11 Female mold made of organic resin,
12 grooves,
14 Copper seed layer,
15 copper layer,
16 metal oxides,
17 Vapor phase treatment chamber,
18 formic acid gas,
19 Insulating substrate,
20 Insulating organic resin film,
21 Metal Master,
22p Liquid organic resin layer,
22 Organic resin layer,

Claims (6)

Preparing an organic resin layer of a mold having a three-dimensional microstructure on the surface;
On the surface of the organic resin layer, a metal layer that completely embeds the three-dimensional microstructure and forms a common support portion is formed, and a bond through a metal oxide is bonded to the interface between the organic resin layer and the metal layer. Forming, and
Exposing the organic resin layer to formic acid gas, reducing the metal oxide at the interface with the metal layer with formic acid permeating the organic resin layer, and cutting the bond between the metal layer and the organic resin layer; ,
A method for producing a microstructure including Peeling the metal layer from which the bond has been cut off from the organic resin layer;
Pushing the metal layer peeled from the organic resin layer into the softened organic resin layer;
Removing the common support portion of the metal layer above the organic resin layer by chemical mechanical polishing;
The method for producing a microstructure according to claim 1, further comprising: Storing the metal layer with the bond cut in the organic resin layer;
The method for producing a microstructure according to claim 1, further comprising: Preparing a master metal layer having a three-dimensional microstructure on the surface;
An organic resin layer that completely embeds the three-dimensional microstructure and forms a common support portion is applied and cured on the surface of the metal layer, and a metal oxide is interposed at the interface between the metal layer and the organic resin layer. Forming a bond;
Exposing the organic resin layer to formic acid gas, reducing the metal oxide at the interface with the metal layer with formic acid permeating the organic resin layer, and cutting the bond between the metal layer and the organic resin layer; ,
A method for producing a microstructure including Peeling the organic resin layer from which the bond has been cut off from the metal layer;
Forming a metal layer that completely embeds the three-dimensional microstructure on the surface of the peeled organic resin layer and also forms a common support;
The method for producing a microstructure according to claim 4, further comprising: Preparing an organic resin layer of a mold having a three-dimensional microstructure on the surface;
On the surface of the organic resin layer, a metal layer that completely embeds the three-dimensional microstructure and forms a common support portion is formed, and a bond through a metal oxide is bonded to the interface between the organic resin layer and the metal layer. Forming, and
Exposing the organic resin layer to formic acid gas, reducing the metal oxide at the interface with the metal layer with formic acid permeating the organic resin layer, and cutting the bond between the metal layer and the organic resin layer; ,
Embedding the metal layer in the insulating organic resin layer of the support substrate provided with an insulating organic resin layer, removing the common support portion, and creating a circuit board;
A circuit board manufacturing method including:

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