JPH07202440A - Production of wiring board - Google Patents

Abstract

PURPOSE:To deposit an insulating film while realizing sufficient adhesion and coverage by ion assist deposition. CONSTITUTION:A wiring board 6 for depositing an insulating film of metal oxide is held by a substrate holder 5. High vacuum is established in a vacuum chamber 1 and a mixture of an inert gas e.g. argon, and an active gas, e.g. oxygen, is subjected to ionization and projected from an ion gun 9 through a shutter toward the wiring board 6 placed in the vacuum chamber 1. On the other hand, a metal oxide 7 is irradiated with an electron beam 8 from an electron gun 3 and heated to be evaporated. The evaporated metal oxide 7 arrives at the wiring board 6 when the shutter 4 is opened. This method improves step coverage of an insulating film 23 at a level difference part 22 of the pattern, as well as the adhesion, when the insulating film 23 is formed on a lower wiring layer 21 formed on a substrate 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a wiring board including a wiring layer and an insulating film made of a metal oxide film. More specifically, the present invention relates to a method for manufacturing a wiring board having an insulating film with good step coverage.

[0002]

2. Description of the Related Art Conventionally, a multilayer wiring board having a plurality of metal wiring layers, in which an interlayer insulating film is formed between respective wiring layers, has been widely used.

As such an interlayer insulating film, use of an organic resin film such as a polyimide film or a metal oxide film made of an oxide of a metal such as Si or Al can be considered. From the viewpoint, a metal oxide film is preferable.

As a method for forming such a metal oxide film as an interlayer insulating film, a PVD method such as a vacuum deposition method, a sputtering method, an ion plating method, a low pressure CVD method, a plasma CVD method, an ECRCVD method or the like is used. CV
The D method is known. Among them, the CVD method has a problem in safety because it uses a special flammable gas or a toxic gas. On the other hand, the PVD method does not have such a problem in safety. Among PVD methods, the vacuum deposition method, which has a relatively high film formation rate and excellent film thickness controllability, is preferred.

A method of forming an interlayer insulating film of a multilayer wiring board by such a vacuum evaporation method will be described with reference to FIG. In this method, as shown in FIG. 3, the vacuum chamber 1, the vapor deposition material holder 2 located at the bottom of the vacuum chamber 1, the electron gun 3 arranged on the side of the holder 2, and the holder 2 above the holder 2. A vacuum vapor deposition device 10 mainly composed of a shutter 4 arranged to control the flight of vaporized vapor deposition material and a substrate holding jig 5 placed above the vacuum chamber 1.
Use 0.

First, the substrate holder 5 holds the multilayer wiring board 6 on which an interlayer insulating film made of a metal oxide is to be formed.
On the other hand, the metal oxide 7 as a vapor deposition material is placed on the vapor deposition material holding table 2. The inside of the vacuum chamber 1 is set to a high degree of vacuum, and the electron beam 8 is emitted from the electron gun 3 to the metal oxide 7
Irradiate, heat and evaporate. The evaporated metal oxide 7 is deposited on the metal wiring layer of the multilayer wiring board 6 held by the substrate holding jig 5 by opening the shutter 4 to form a film.

[0007]

However, in the above-mentioned conventional vacuum deposition method, in order to improve the adhesion of the interlayer insulating film made of a metal oxide to the multilayer wiring board, the multilayer wiring board is formed with 250 layers at the time of film formation. Since it has to be heated to ˜300 ° C., work efficiency is lowered, heat management is difficult, and the multilayer wiring board is thermally deteriorated.
In addition, the interlayer insulating film thus formed has a low density of metal oxides due to weak chemical bonding between metal oxide molecules or particles forming the insulating film. However, there is a problem that the surface smoothness of the interlayer insulating film is deteriorated and the step coverage of the interlayer insulating film becomes insufficient. For example, as shown in FIG. 4, the step coverage of the interlayer insulating film 43 at the pattern step portion 42 of the lower metal wiring layer 41 patterned on the substrate 40 of the multilayer wiring board becomes insufficient. Therefore, when a metal thin film is vapor-deposited on the interlayer insulating film 43 to form an upper metal wiring layer, the upper metal wiring layer may be disconnected, or the lower metal wiring layer and the upper metal wiring layer may be short-circuited. was there.

The present invention is intended to solve the above-mentioned problems of the prior art, and when manufacturing a wiring board having a wiring layer and an insulating film, the insulating film is used to control the temperature of the wiring board. It is an object of the present invention to form a film so that sufficient adhesion and sufficient step coverage can be realized even at a relatively low temperature (for example, about 100 ° C. or lower).

[0009]

The present inventors have used, instead of the vacuum vapor deposition method, an ion assisted vapor deposition method in which reactive vapor deposition is performed under ion discharge conditions of a mixed gas of an active gas and an inert gas. Then, it is found that the above object can be achieved by forming an insulating film made of a metal oxide,
The present invention has been completed.

That is, the present invention provides a method for manufacturing a wiring board including an insulating film made of a metal oxide, wherein the insulating film is formed by an ion assisted vapor deposition method.

The present invention will be described in detail below.

The method of manufacturing a wiring board of the present invention is characterized in that the insulating film is formed by an ion assisted vapor deposition method.
Therefore, the manufacturing method of the present invention can be widely applied to the manufacture of a wiring board having an insulating film made of a metal oxide, and can be applied to the types and the number of layers of supporting substrates and metal wiring layers, the patterning method of metal wiring layers, and the like. There is no particular limitation. As the metal oxide forming the insulating film, SiO ₂ , Al ₂ O ₃ , T
iO _{2 and the} like can be exemplified.

A method of forming an insulating film by the ion assisted vapor deposition method will be described below.

The ion assisted vapor deposition method used in the present invention is a method of performing reactive vapor deposition while irradiating an ion beam generated from an ion discharge of a mixed gas of an active gas and an inert gas. In this method, as shown in FIG. 1, a vacuum chamber 1, a vapor deposition material holding base 2 located at the bottom thereof, an electron gun 3 arranged on the side of the holding base 2, and an upper side of the holding base 2, A shutter 4 for controlling the flight of the evaporated vapor deposition material, a substrate holding jig 5 arranged above the vacuum chamber 1, an ion gun 9 provided below the vacuum chamber 1, and an ion beam 1 from the ion gun 9.
A vacuum vapor deposition apparatus 101 mainly composed of a shutter 11 for controlling the amount of 0 is used.

First, the substrate holder 5 holds the wiring board 6 on which an insulating film made of a metal oxide is to be formed. On the other hand, the metal oxide 7 as a vapor deposition material is placed on the vapor deposition material holding table 2. Then, the inside of the vacuum chamber 1 is set to a high degree of vacuum, a mixed gas composed of an inert gas such as argon and an active gas such as oxygen is ionized, and a vacuum is passed through the shutter 11 from the ion gun 9 toward the wiring board 6. Discharge into chamber 1. On the other hand, the metal oxide 7 is irradiated with the electron beam 8 from the electron gun 3 to be heated and evaporated. The metal oxide 7 thus evaporated reaches the wiring board 6 by opening the shutter 4.

The mixed gas released from the ion gun 9 cleans the surface of the wiring board 6 by the sputtering effect and smoothes the surface of the deposited insulating film made of metal oxide. Moreover, it collides with the metal oxide molecules evaporated in the vacuum chamber 1 and imparts energy thereto. The metal oxide molecules to which energy has been applied can be firmly deposited on the wiring board 6. Therefore, for example, as shown in FIG. 2, when the insulating film 23 is formed on the lower metal wiring layer 21 patterned on the substrate 20 of the wiring board, the step coverage of the insulating film 23 in the pattern step portion 22 is increased. Is good and the adhesion is also good.

The deposition rate of the metal oxide is usually about 1 to 10 Å / min from the viewpoint of step coverage.
Minutes, preferably about 5 angstroms / minute.

[0018]

In the method of manufacturing the wiring layer of the present invention, the insulating layer is formed by the ion assisted vapor deposition method. Therefore, it becomes possible to form an insulating film having good adhesion and good step coverage. Further, in the case of the ion assisted vapor deposition method, the temperature of the wiring board does not exceed about 100 ° C. until the thickness of the insulating film reaches about 10 μm. Thus, it is possible to prevent distortion due to heat. Therefore, a highly reliable wiring board can be obtained by the manufacturing method of the present invention. In particular, the manufacturing method of the present invention can be preferably applied to manufacture a multilayer wiring board in which it is difficult to ensure surface smoothness.

[0019]

The present invention will be described in detail below with reference to the following examples.

Example 1 A wiring board was prepared in which an Al wiring layer having a thickness of 2 μm and a minimum pattern interval of 30 μm was formed on a Si wafer substrate having a thickness of 0.38 mm. This wiring board was placed in the ion assisted vapor deposition apparatus of FIG. 1 and ion assisted vapor deposition was performed on the entire surface of the Al wiring layer under the conditions shown in Table 1.

[0021]

[Table 1] Ion-assisted vapor deposition conditions Vapor deposition material SiO ₂ vapor deposition rate 5 Å / min Vacuum chamber internal pressure 1 × 10 ⁻⁴ Torr Kauffman type ion gun power 60 eV [Introduced gas 3 sccm (Ar / O ₂ = 9/1 (V / V ))] Wiring board temperature of 100 ° C. or less As a result, the adhesion and step coverage of the insulating layer of the obtained wiring board were good.

[0022]

According to the present invention, when a wiring board having a wiring layer and an insulating film is manufactured, the insulating film is used at a relatively low temperature (for example, about 100 ° C. or lower). It is possible to form a film so as to realize sufficient adhesion and sufficient step coverage.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an ion assisted vapor deposition device used in the present invention.

FIG. 2 is a sectional view of a wiring board obtained by the method of the present invention.

FIG. 3 is an explanatory diagram of a vacuum vapor deposition apparatus used in a conventional vacuum vapor deposition method.

FIG. 4 is a cross-sectional view of a wiring board manufactured using a conventional vacuum vapor deposition device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vapor deposition material holder 3 Electron gun 4, 11 Shutter 5 Substrate holding jig 6 Wiring board, multilayer wiring board 7 Metal oxide 8 Electron beam 9 Ion gun 10 Ion beam

Claims (2)

[Claims] 1. A method for manufacturing a wiring board including a wiring layer and an insulating film made of a metal oxide, wherein the insulating film is formed by an ion assisted vapor deposition method. 2. The metal oxide forming the insulating film is SiO 2.
_2. The manufacturing method according to claim 1, which is ₂ .