JPS59106136A - Wiring structure and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a wiring structure which assures high density wiring by forming a first and a second polymer resins in substantially the same chemical composition and selecting the width of lower wiring conductor to the dimension almost the same or smaller than that of the opening. CONSTITUTION:PIQ prepolymer liquid is rotatingly applied as a first polymer resin insulating film 2 on a substrate 1, the thermosetting PIQ film is formed, aluminum is vacuum deposited thereon and it is photoetched. Thereby, a lower wiring conductor 3 in the film thickness of 1mum and width of 4mum is formed. Next, the PIQ prepolymer liquid is rotatingly applied and it is half-hardened. Thereafter, a negative type photo resist is applied and it is exposed and developed in order to form an opening pattern. Then, etching is carried out with an opening size of 4mum square, using the alcohol solution containing tetramethylammoniumhydroxide as the etchant which etches only the half-hardened PIQ but does not etch the hardened PIQ. Thereafter, the final baking is carried out, aluminum is vacuum deposited as the upper wiring conductor and the upper layer wiring conductor 6 is formed by the photo etching.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wiring structure and a method for manufacturing the same, and in particular, the present invention relates to a wiring structure and a method for manufacturing the same, and in particular, a multilayer wiring structure in which the wiring structure is multilayered and the wiring interlayer insulating film is made of polymer resin. The present invention relates to a wiring structure that can be formed with high density and a manufacturing method thereof. The wiring structure of the present invention is not only effective for semiconductor integrated circuits, but also for wiring substrates such as thermal recording elements,
It has an extremely wide range of applications as it can be applied to the substrate of a magnetic thin film head, and furthermore to the wiring on a magnetic substrate such as a timing valve memory element.

Conventional multilayer wiring using polymer resin as an insulating film is made of, for example, polyimide resin or polyimide-based polyimide/isoindoquinazolinedione resin (for example, PIQ
(Trademark of Hitachi Chemical Co., Ltd.)) is known. The reason why polyimide thread resin is preferred is that its precursor (prepolymer) is in a solution state and can be easily applied to a substrate by means such as spin coating. This is because it has a high heat resistance that can withstand temperatures of 400° C. to 500° C. and is suitable for forming wiring in semiconductor integrated circuits. The polyimide resin used here is a polymer obtained by reacting aromatic diamine and acid dianhydride, and is a polymer obtained by reacting aromatic diamine with acid dianhydride.
Toray Industries, Inc.) and Pyre-ML (DuPont) are commercially available in varnished form, and for semiconductors,
In particular, Pyralin (DuPont) is commercially available. In addition, polyimide-based polyimide isoindoroquinazolinedione resin is a resin obtained by reacting aromatic diamine, aromatic diaminocarponamide, and acid dianhydride.
It has better heat resistance than ordinary polyimide resin, and has PIQ
(Hitachi Chemical Co., Ltd.) is commercially available.

The structure of the conventional resin-insulated multilayer wiring and its manufacturing method will be described below with reference to FIG. 1a.

After forming the first layer of wiring (not shown) on the substrate 1,
A PIQ prepolymer is applied and finally heated and cured at a temperature of 300° C. or higher to form a PIQ film 2' which is a first polymer resin insulating film. After forming an opening at a predetermined position (the opening is not shown), a second layer of wiring conductor 3' is formed, and a PIQ film 4, which is a second polymer resin insulating film, is formed on this.
', an opening 5' was formed, and a third layer wiring conductor 6' was further formed. By repeating the formation of the PIQ film, the formation of the openings, and the formation of the wiring conductor in this way, it is possible to form a multilayer wiring layered with any number of layers.

Incidentally, the openings were formed by covering the PIQ film with a negative type photoresist, and after exposure and development, selectively etching with a mixed solution of hydrazine hydrate and ethylenediamine.

This etching solution etches the completely cured PIQ film. Therefore, if the opening mask alignment deviates and the opening 5' deviates from the width of the lower layer wiring conductor 3', the lower layer P
Since the IQ film 2' is also etched, this is not preferable in terms of reliability of the wiring structure. Therefore, the width of the lower wiring conductor 3' had to be made sufficiently wide, taking into account the precision of alignment of the openings 5 and the variations in the dimensions of the openings. For this reason, the width and spacing of the wiring cannot be made sufficiently small, and the formation of high-density multilayer wiring through miniaturization of the wiring has been hindered.

An object of the present invention is to provide a new means that eliminates the above-mentioned drawbacks of the prior art, thereby providing a structure capable of high-density wiring.

The wiring structure of the present invention for the above purpose is characterized by a first polymer resin insulating film provided on a substrate, and a wiring conductor in a lower layer extending on the first polymer resin insulating film. layer, covering the first polymer resin insulating film and the lower wiring conductor layer,
a second polymer resin insulating film having an opening at a predetermined position; an upper wiring conductor layer on the second polymer resin insulation film, at least a portion of which is in contact with the lower wiring conductor through the opening; In the structure, the first and second polymer resin insulating films have substantially the same chemical composition, and the width of the underlying wiring conductor is approximately equal to or smaller than the dimension of the opening.

The method for manufacturing a two-layer wiring structure of the present invention is characterized by the step of providing a first polymer resin insulating film on a substrate, and the step of forming a lower layer on the first polymer resin insulating film. forming a wiring conductor layer, a second polymer having substantially the same chemical composition as the first polymer resin insulation film so as to cover the lower wiring conductor layer and the first polymer resin insulation film; A first heating step in which a Solebolimer solution for forming a resin insulating film is applied and dried, and heated at a temperature that does not completely cure to form a semi-cured film of a second polymeric resin insulating film; A process of forming openings in the semi-cured film using an etchant that etches the molecular resin but does not etch the completely cured first polymer resin insulating film; a second heating step to form a polymeric resin insulating film, and a layer of an upper wiring conductor extending over the second polymeric resin insulating film, at least a portion of which is in contact with the lower wiring conductor at the opening portion; In the above, it is preferable that the width of the lower layer wiring conductor is approximately equal to or smaller than the dimension of the opening.

Preferred polymer resins for the first and second polymer resin insulation films in the present invention are polyimide resins, such as polyimide resins obtained by reacting aromatic diamines and acid dianhydrides; Other examples include polyimide-based polyimitoisointroginazolinedione resins obtained by reacting aromatic diamines, aromatic diaminocarbonamides, and acid dianhydrides.

In the present invention, several types of etchant for etching the semi-cured polyimide resin have been found, depending on the degree of curing. Table 1 shows them.

In Table 1, TMA is an abbreviation for tetramethylammonium hydroxide, and HHED is a mixture of hydrazine hydrade and ethylenediamine.

Table 1 can be interpreted as follows.

The TMA solution etches a polyimide resin film cured at around 140°C in about 1 minute, but does not etch a film cured at 200°C or higher.

HHED + water etches a film cured at around 140°C in 30 seconds, and etches a film hardened at around 220°C in 5 seconds.
Etching takes about 10 minutes, or substantially no etching occurs within about 30 seconds, and furthermore, a film cured at around 350 DEG C. is hardly etched. With HHED, a film cured at around 140°C is etched in about 20 seconds, a film cured at around 220°C is etched in about 2 minutes, or is not substantially etched in about 20 seconds, and then etched in about 3 minutes.
A film cured at around 50°C is etched in 10 to 20 minutes, or substantially not etched in about 2 minutes. Here, the temperature around 140° C. is approximately ±40° C., and the same applies to other cases. Further, the concentration of the TMA solution is in the range of 3 to 30%, and the solvent is water or alcohol, particularly methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, etc. HHED is an etching solution in which the mixing ratio of hydrazine hydrate (abbreviated as HH) and ethylenediamine (abbreviated as ED) is in the range of 8/2 to 2/8, and the mixed solution with water is This is an etching solution containing about 3 to 30% water.

When choosing a TMA solution as the etching solution, it is better to use alcohol as the solvent. In an aqueous solution, the wiring material Al
This is because there is a possibility of corrosion. For alcohol,
Although there is no particular difference, it can be said that methanol is preferable.

HHED is preferably in the range of 5/5 to 2/8, since the higher the concentration of erylenediamine, the better the microprocessability.

The present inventors have confirmed that the relationships in Table 1 are applicable to ordinary polyimide and PIQ.

Therefore, from the results in Table 1, when using PIQ as a polymer resin, first bake the first PIQ film at 350°C, then bake the second PIQ film at 140°C so that the TMA solution becomes HHED + water. The purpose can be achieved by etching with HHED solution, or by baking at 220° C. and etching with HHD+water or HHED.

Hereinafter, the present invention will be specifically explained with reference to FIG. 1B, focusing mainly on the manufacturing process and also on the structure.

On the substrate 1, a first polymer resin insulating film, for example,
A sufficiently hardened PIQ film 2 is formed, and a lower wiring conductor 3 is formed thereon. The width may be narrow enough as required. Next, a PIQ prepolymer for the second polymer resin insulating film is applied and semi-cured at a temperature of 200° C. or less.

Next, a photoresist film is formed, and an opening 5 is formed with an etching solution that does not etch the PIQ film 2, which has already been sufficiently baked at a temperature of 200° C. or higher, but etches the semi-hardened PIQ. Even if there is a part of the opening that deviates from the wiring conductor 3 in the lower layer and protrudes, this way the PIQ
Film 2 is not etched and is stable. After that, the photoresist was removed and the semi-cured PIQ film was completely cured.
A PIQ film 4, which is a second polymer resin insulating film, is formed, and an upper layer wiring conductor 6 is formed. That is, the lower layer wiring conductor 3 in FIG. 1b can be set thinner than the lower layer wiring conductor 3' in FIG. 1a.

As described above, according to the present invention, high-density wiring can be realized by miniaturizing the wiring.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 This will be explained with reference to FIG. 1b.

A PIQ film was formed on the substrate 1 as the first polymer resin insulating film 2 . To form the PIQ film, PIQ prepolymer liquid (viscosity 1100 cP, concentration approximately 15%) was heated at 3000 rpm.
The coating was spin-coated at 200° C. for 60 minutes and then heated at 350° C. for 30 minutes to harden, forming a PIQ film with a thickness of 2 μm. On top of this, Al was vaporized and photoetched to form the lower layer wiring conductor 3. The Al film thickness was 1 μm and the width was 4 μm. Next, the PIQ prepolymer solution was spin-coated again in the same manner as described above, and this time it was cured at 150° C. for 60 minutes. After that, apply negative type photoresist OMR83.
(manufactured by Tokyo Ohka) was coated, exposed and developed to form an aperture pattern. Tetramethylammonium hydroxide (hereinafter referred to as TM
An alcohol solution (in this case, a methanol bath solution) containing 25% of A) was used. Assuming the opening size to be 4 μm,
When etching was performed for 60 seconds, some portions were formed 1.5 μm away from the wiring conductor in one direction due to misalignment, but the underlying PIQ film was not etched and remained stable. Thereafter, final baking was performed at 350° C. for 30 minutes, and an upper layer wiring conductor was formed by vacuum evaporating Al as an upper layer wiring conductor and photoetching.

Example 2 This will be explained with reference to FIG. 1b.

As in Example 1, a P1Q film was formed on the substrate 1 as the first polymer resin insulating film 2. A lower layer wiring conductor 6 was formed thereon by Al vapor deposition and photoetching. Next, a PIQ prepolymer solution was applied by spin coating, and 15
It was cured at 0°C for 60 minutes.

After that, positive type photoresist AZ1350J (
Shipley Co., Ltd. (trade name) was applied and the aperture pattern was exposed. Next, the resist pattern was developed for 90 seconds using AZ135DJ developer MF312 (trade name of Shipley), and at the same time the semi-cured PIQ film was etched to form an opening. MF312 is an approximately 10% aqueous solution of TMA, which dissolves the exposed portion of AZ1350J and
It has the ability to etch semi-cured PIQ at 0°C.

However, the processability for fine through holes is inferior to that of an alcohol solution of TMA. When the width of the lower layer wiring conductor was 7 μm and the through-hole dimension was 7 μm□, the alignment of the through holes was misaligned with the wiring by a maximum of about 1.5 μm, but the underlying PIQ film had no effect. I didn't take it. Thereafter, PIQ was completely cured at 350° C., and an upper layer wiring conductor was formed in the same manner as in Example 1.

Example Referring to FIG. 1b, a PIQ film was formed as the first polymer resin insulating film 2 on the substrate 1 in the same manner as in Example 1. A lower layer wiring conductor 6 was formed thereon by Al vapor deposition and photoetching. Next, a PIQ prepolymer solution was spin-coated and cured at 200°C for 60 minutes. After that, OM
R83 was applied, exposed, and developed to form an opening pattern. Next, an etching solution was prepared by adding water at a volume of 5 to 50% to an etching solution based on a mixed solution of hydrazine hydrate 7 to 3 and ethylenediamine 3 to 7.
The semi-cured PIQ membrane was enotinked. A mixed solution of hydrazine hydrate and ethylenenoamine is a good etching solution for a PIQ film completely cured at a temperature of 300°C or higher, but when water is mixed with it, the etching rate for a completely cured PIQ film is slow. Therefore, the etching rate ratio with the PIQ film semi-cured at around 200° C. becomes large.

Therefore, the semi-cured PIQ film can be processed without substantially etching the underlying PIQ. Furthermore, this etching solution has excellent processability and allows the formation of through holes of 3 μm square. Wiring was formed with the width of the lower wiring conductor being 3 μm and the through hole opening being 3 μm, and even if only misalignment occurred, the underlying PIQ film was hardly damaged. The amount of water to be included is preferably between 5% and 30%.
The higher the etching temperature, the lower the etching rate; conversely, the semi-curing temperature of the PIQ film is preferably about 180°C to 280°C, and the higher the curing temperature, the lower the etching rate.

The optimum moisture content and semi-curing temperature can be determined by experiment. -For example, hydrazine hydrate 35
%, ethylenediamine 55%, moisture 10%, PIQ curing temperature 210°C, and etching time 8 minutes.

Thereafter, the PIQ was completely cured, and an upper layer wiring conductor was formed in the same manner as in Example 1.

Example 4 A polymer obtained by reacting equimolar amounts of pyromellitic dianhydride and noaminophogonyl ether was used as a polyimide film of a polymer resin insulating film.

Using N-methyl-2-pyrrolidone solvent, concentration 15%,
It was used as a liquid with a viscosity of 1200 cP. Thereafter, in the same manner as in Example 1, a lower wiring conductor was formed, and a first polyimide film as a first polymer resin insulating film was formed and etched. The first polyimide membrane was beta-beted at a final temperature of 350°C. Next, a second polyimide film for the second polymer resin insulating film was applied, semi-cured at 150°C, and etched with TMA methanol solution in the same manner as in Example 1, but misalignment occurred. However, the completely cured polyimide film underneath was not attacked and remained stable. Thereafter, the entire structure was further baked at 350° C., and then an upper layer wiring conductor was formed in the same manner as in Example 1.

Example 5 Almost the same process as in Example 1 was carried out, but the processing operations shown below were partially different.

As the first polymer resin insulating film, the first PIQ film was
After baking at 0° C., Al was vapor deposited thereon and a lower wiring conductor was formed by photoetching. Then P.I.
The paste coated with the polymer solution of Q was baked at 140°C for 60 minutes, and HHED (HH
/ED=7/3) for 20 seconds. In this amount of time, the first PI of the base baked at 350℃
Even if the Q film was exposed, through holes could be formed with virtually no effect. After this, the whole 3
It was baked at 50° C., and an upper layer wiring conductor was formed in the same manner as in Example 1.

Example 6 The same steps as in Example 5 were followed, but in particular the following processing operations were carried out.

The second PIQ film for the second polymer resin insulating film was baked at a temperature of 200° C., and etched for 2 minutes using HHED (HH/ED=7/3) using OMR83 as a photoresist. With this level of etching time, the etching time is still 350
The underlying PIQ film, which had been baked at a temperature of .degree. C., was stable with almost no damage.

In the above, examples have been mainly described for the wiring conductor layer up to the third layer wiring conductor layer, but it is clear that the present invention can also be applied to the upper layer wiring conductor layer of the fourth layer and above. The invention has a significant effect on high-density multilayer wiring.

[Brief explanation of drawings]

Figure 1a is a cross-sectional view of a wiring structure with a conventional structure.
FIG. b is a sectional view of a wiring structure according to the invention. 1...Substrate 2...First polymer resin insulating film 3...Lower layer wiring conductor 4...Opening 5...Second polymer resin insulating film 6...Upper layer wiring conductor Patent attorney Junnosuke Nakamura

Claims (5)

[Claims] (1) A first polymer resin insulating film provided on a substrate, a lower wiring conductor layer extending on the first polymer resin insulating film, and a layer between the first polymer resin insulating film and the lower wiring conductor layer. a second polymer resin insulating film that covers the lower wiring conductor layer and has an opening at a predetermined position; In a wiring structure having a wiring conductor and a layer of wiring conductor in a contacting upper layer,
The first polymer resin insulating film and the second polymer resin insulating film have substantially the same chemical composition, and the width of the lower wiring conductor is approximately equal to or smaller than the dimension of the opening. A wiring structure characterized by: (2) The polymer resin of the first and second polymer resin insulating films is a polyimide resin, preferably a polyimide resin or an aromatic resin obtained by reacting an aromatic diamine and an acid dianhydride. Claim 1, which is a polyimide isoindoquinazolinedione resin obtained by reacting a group diamine, an aromatic diaminocarbonamide, and an acid dianhydride.
Wiring structure described in section. (3) providing a first polymer resin insulating film on the substrate;
forming a lower wiring conductor layer on the first polymer resin insulating film, forming the first polymer resin so as to cover the lower wiring conductor layer and the first polymer resin insulating film; A sol polymer solution of a polymer resin for forming a second polymer resin insulation film having substantially the same chemical composition as the insulation film is coated and dried, and heated at a temperature that does not completely cure the second polymer resin insulation film. First heating step for forming a semi-cured film of the polymeric resin insulating film The polymeric resin of the biocured film that is not completely cured after the first heating step is etched or completely cured of the first polymeric resin insulating film. A step of forming an opening in the semi-cured film using an etching solution that does not etch the molecular resin insulating film, a second heating step of completely curing the semi-cured film to form a second polymer resin insulating film, and , forming a layer of an upper wiring conductor extending over the second polymer resin insulating film in contact with the outer lower wiring conductor at least in part at the outer opening. A method for manufacturing a wiring structure. (4) The method of manufacturing a wiring structure according to claim 3, wherein the width of the lower layer wiring conductor is approximately equal to or smaller than the dimension of the opening. (5) The polymer resin of the first and second polymer resin insulation films is a polyimide resin, preferably a polyimide resin or an aromatic diamine obtained by reacting an aromatic diamine and an acid dianhydride. This is a polyquimidoisoindoquinazolinedione resin obtained by reacting aromatic diaminocarponamide with an acid dianhydride, and the etching solution is a mixture of tetramethylammonium hydroxide, hydrazine hydrate, and ethylenediamine. or, claim 3 or 4, which is a mixture of hydrazine hyrolate and ethylenediamine and water.
A method for manufacturing a wiring structure as described in Section 1.