JPH0125162B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a method for molding a wiring structure for electronic components such as a thin film magnetic head or a semiconductor device, and particularly relates to a molding method for flattening an insulating layer of this wiring structure. be. [Background of the Invention] In recent years, the patterns of electronic components molded by thin film processes have become increasingly finer.
There is a demand for multi-layered materials in which multiple layers are laminated to form a pattern. In order to meet this demand, a technique for flattening the unevenness of the underlying material is required. To meet this requirement, a method of using an organic polymer compound for the insulating layer has been known. For example, condensed polyimide is used as an interlayer insulating film for multilayer wiring of semiconductor devices. This is because condensed polyimides have various excellent properties (for example, processability, heat resistance, electrical properties, and mechanical properties). However, recently, even more precise planarization has been required in the field of magnetic heads.
Furthermore, in the field of semiconductors, when there are more than two layers or when miniaturization progresses, the requirements for planarization become extremely strict. The above-mentioned condensed polyimides are no longer able to meet such demands. That is, as shown in FIG. 1, a wiring structure is formed by forming a wiring 2 on a substrate 1, applying condensed polyimide on the wiring 2, and curing it to form a polyimide insulating layer 3. , due to the level difference in the wiring 2 formed on the substrate 1, the polyimide insulating layer 3 covering the wiring 2 is not at the same height on the wiring 2 and on the substrate 1 between the wiring 2. First, there was a drawback in that the surface of the polyimide insulating layer 3 was undulated. For this reason, when a magnetic film, for example, is formed on this insulating layer, the magnetic film itself also undulates, resulting in a problem that the magnetic properties deteriorate. Further, when applying the photolithography technique, for example, when performing fine multilayer wiring of a semiconductor device, it has become a big problem. In other words, photolithography generally spin-coats photoresist, exposes it, and develops it to obtain an etching resist pattern. However, the photoresist is thicker in the concave parts of the step and thinner in the convex parts, making it difficult to achieve uniform exposure conditions. Therefore, even when resist patterns with the same line width are required, unnecessarily narrow portions or unnecessarily wide portions occur, making it extremely difficult to form multilayer fine patterns. [Object of the Invention] An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a method for forming a wiring structure that can obtain a flat insulating layer. [Summary of the Invention] In order to achieve the above object, the present inventors conducted numerous experiments and various studies regarding the fluidity of the insulating material of the wiring structure, and as a result, the following general formula [A It has been found that a flat insulating layer can be obtained by coating and curing the addition polymerizable imide oligomer shown in [] or [B]. (However, R ¹ is

[Formula] n = 1 to 10) (However, R ² is

[Formula] Ma Taha

[Embodiments of the invention]

Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Referring to FIG. 2, a wiring structure in which a single-layer conductor pattern is planarized will be described. A conductor layer with a thickness of about 2 μm was deposited on the entire surface of the substrate 1 by vapor deposition (the same effect was obtained even if deposited by sputtering), and wiring with a line width of 8 μm and a line spacing of 4 μm was formed using a photoetching technique. 2 conductor patterns were formed (the same effect was obtained even if this wiring pattern fitting technique was used). Next, an oligomer having a number average molecular weight of about 1500 shown in the following general formula [A] is dissolved in N-methyl-2-pyrrolidone.
40% by weight solution, spin coating, then 200℃
Heat treatment was performed for 30 minutes at 350° C. in an N ₂ atmosphere for 30 minutes to form an insulator layer 4 having a thickness of 4 μm.
The upper surface of the insulator layer thus formed had a good flat surface with a waviness height of 0.15 μm or less.
This value is 7.5% or less of the surface unevenness caused by the wiring before forming the insulator layer. (However, R ¹ is

[Formula] n = 1 to 10) Example 2 In this example, an example will be described in which a wiring structure is formed by flattening a plurality of layers of conductor patterns. In exactly the same manner as in Example 1, a single layer wiring structure shown in FIG. 2 was molded. Next, although not shown here, a pattern of wiring 2 is formed on the insulating layer 4 in the same manner as in Example 1, and then the pattern of the wiring 2 is formed on the insulating layer 4.
was formed to form a two-layer wiring structure. The height of waviness on the upper surface of the upper insulating layer thus formed was 0.2 μm or less. Furthermore, no blisters or cracks were observed on the surface after the upper conductor was vapor-deposited (or sputtered), confirming that it could sufficiently withstand the vapor-deposition (or sputtering) process. Example 3 In the same manner as in Example 1, a wiring structure with a flattened single-layer conductor pattern was molded. However, the insulating layer was formed using an oligomer having a number average molecular weight of about 1300 as represented by the following general formula [B ₁ ]. That is, the oligomer was dissolved in N-methyl-2-pyrrolidone to make a 45% solution by weight, spin coated, and then
200°C for 30 min, then 350°C in _N2 atmosphere.
A heat treatment was performed for 30 minutes to form an insulating layer with a thickness of 4 μm. The height of waviness on the upper surface of the insulator layer thus formed was 0.2 μm or less. (However, R ² is

[Formula] n=1 to 10) Example 4 In the same manner as in Example 1, a wiring structure having a flattened single-layer conductor pattern was molded. However, the insulating layer was formed using an oligomer having a number average molecular weight of about 2000 as represented by the following general formula [B ₂ ]. Briefly, the oligomer was dissolved in N, _N -dimethylacetamide to give a 40 wt.
A heat treatment was performed for 30 minutes to form an insulating layer with a thickness of 4 μm. The height of waviness on the upper surface of the insulating layer thus formed was 0.15 μm or less. (However, R ² is

〔Effect of the invention〕

As detailed above, according to the method of the present invention, the insulator layer can be planarized with high precision.
The operation of photolithography to form fine patterns has become advantageous, and it has become possible to manufacture three-dimensional wiring structures with multiple layers. Particularly, when a thin film magnetic head is constructed, it is effective in terms of the magnetic circuit because unnecessary irregularities are not created in the upper magnetic layer, and an excellent effect is produced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional wiring structure having a single layer conductor. FIG. 2 is a sectional view of a wiring structure having a single layer conductor according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a wiring structure having multiple layers of conductors as an example of a thin film magnetic head according to another embodiment of the present invention. 1...Substrate, 2...Wiring, 3...Insulator layer (conventional example), 4...Insulator layer, 5...Ceramic substrate,
6... Base film, 7... Lower magnetic layer, 8... Inorganic insulating film, 9... First layer conductor coil, 10... First layer
Insulator layer, 11... Second layer conductor coil, 12...
Second insulator layer, 13...upper magnetic layer.

Claims (1)

[Scope of Claims] 1. A wiring structure in which a conductor layer having a predetermined pattern is formed on a substrate, and then an insulator layer having a predetermined pattern is formed on the conductor layer and then molded, the following [A] Alternatively, a method for forming a wiring structure, characterized in that the insulating layer is formed using a compound represented by the general formula [B]. (However, R ¹ is [Formula] n = 1 to 10) (However, R ² is [Formula] or [Formula] n = 1 to 10) 2. Form a conductor layer with a predetermined pattern on the substrate, and form an insulator layer with a predetermined pattern on the conductor layer. Further, in a wiring structure in which a conductor layer and an insulator layer having a predetermined pattern are repeatedly laminated on the insulator layer to form a plurality of conductor layers, the following general [A] or [B] may be used. A method for forming a wiring structure, comprising forming the insulating layer using a compound represented by the formula. (However, R ¹ is [Formula] n = 1 to 10) (However, R ² is [Formula] or [Formula] n = 1 to 10)