JPH06348034A - Pattern forming method - Google Patents

Abstract

PURPOSE:To provide the method capable of forming deposited layers varying in etching resistance to pattern shapes with a high resolution and forming the patterns by etching with the high resolution. CONSTITUTION:This pattern forming method includes a stage for forming the first layer 2 on a substrate 1 and patterning and forming the second layer 3 of the material different from the material of the first layer 2 on the surface of the first layer 2, a stage for bringing the substrate surface formed with the first layer 2 and the second layer 3 into contact with a soln. 6 contg. plural kinds of resins varying in materials thereafter and allowing the resin layers 8, 7 different from each other to grow respectively selectively on the first and second layers 2, 3 and a stage for etching the resin layer 8 grown on the first layer 2 and the first layer 2 with the resin layer 7 grown on the second layer 3 as a mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing method, and more particularly to a pattern forming method.

[0002]

2. Description of the Related Art As elements and wirings are miniaturized due to higher density of semiconductor integrated circuits, it is required to form resist patterns with higher resolution in the process of manufacturing these.

However, the surface of the substrate to be processed has irregularities such as stepped elements, and in the method of coating a resist on the surface of the substrate like a single-layer resist process and processing it into a pattern by exposure and development, the influence of the base is affected. Accordingly, it is difficult to form a fine resist pattern with a high aspect ratio and with high dimensional accuracy, and thus it is difficult to accurately form a fine element or wiring.

For this reason, a multi-layer resist process in which several resist layers are provided is currently receiving attention. A typical multi-layer resist process is a three-layer resist process. This is a flattening layer that flattens irregularities such as element steps on the substrate surface, an intermediate layer that is provided on this layer and serves as a mask when etching, and pattern exposure that is actually provided on this layer is performed. It is a method of forming a resist pattern from the exposed photosensitive layer.

Specifically, the photosensitive layer is first subjected to pattern exposure, then developed to form a pattern, and then the intermediate layer is etched by plasma or the like using CF ₄ gas as a mask. A pattern is transferred to the intermediate layer, and the flattening layer is etched by oxygen plasma or the like using the intermediate layer pattern as a mask to form a resist pattern.

According to the three-layer resist process, it is possible to reduce the influence of the element step on the surface of the substrate and perform the exposure and development under ideal conditions separated from the underlying substrate. However, this process had the following problems. That is, when etching the intermediate layer, the resist of the uppermost layer needs to be formed to be thick to some extent so that the resist pattern of the photosensitive layer can sufficiently withstand this etching, but in general, when the resist film thickness increases, There is a problem that the resolution of the resist pattern is deteriorated because the resist itself has an effect of absorbing the exposure light and a wide depth of focus of the exposure light cannot be secured.

[0007]

In the three-layer resist process as described above, the resist pattern of the photosensitive layer must be formed to be thick to some extent in order to increase the etching resistance, and the influence of the absorption of exposure light of the resist itself is affected. However, there is a problem that the resolution of the resist pattern is deteriorated because the exposure light does not have a wide focal depth. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pattern forming method which solves the problem of resolution deterioration.

[0008]

That is, according to the present invention, a step of forming a first layer on a substrate, and a pattern of a second layer made of a material different from that of the first layer on the surface of the first layer are patterned. Forming the layer, selectively growing layers of different materials on the surfaces of the first and second layers, and using the growth layer formed on the pattern of the second layer as a mask, And a step of etching the growth layer on the layer and the first layer.

The present invention further comprises the step of forming a first layer on the substrate, and the step of patterning a second layer made of a material different from that of the first layer on the surface of the first layer. Contacting the surface of the substrate on which the first layer and the second layer are formed with a solution containing a plurality of resins of different materials,
Selectively growing different resin layers on the layer of
And a step of etching the resin layer grown on the first layer and the first layer using the resin layer grown on the second layer as a mask. It is a thing.

[0010]

According to the pattern forming method of the present invention, the first
Layers selectively grown on the surface of the second layer and the surface of the second layer, and the growth layer formed on the pattern of the second layer is used as a mask and the growth layer on the first layer and the first layer. 1
Since the second layer is etched, the pattern of the second layer is not directly etched, but it is possible to form this second layer thinly and process this layer into a pattern with high resolution.
Then, the growth layer is formed with the same resolution as the pattern of the second layer and the etching is performed, whereby the pattern can be formed with high resolution.

[0011]

Embodiments of the pattern forming method according to the present invention will be described below in detail with reference to the drawings. First Embodiment FIG. 1 is a process schematic diagram showing a first embodiment of the pattern forming method according to the present invention.

First, as shown in FIG. 1 (a), a substrate 1 (concavities and convexities are omitted in the figure) is used, and on this surface,
An ethyl cellosolve acetate solution containing a cresol novolac resin having a weight average molecular weight of about 8,000 and a 1,2-naphthoquinonediazide-5-sulfonic acid ester compound was spin-coated with a spinner, and then 200 ° C. on a hot plate. Baking was performed for 5 minutes to form a planarizing resin layer having a film thickness of 1.5 μm as the first layer 2. As shown in FIG. 1 (b), a xylene solution containing an organosilicon resin having a weight average molecular weight of about 10,000 and an aromatic bisazide compound is spin-coated on the surface of the first layer 2 using a spinner. And then 2 on the hot plate
Baking was performed at 00 ° C. for 10 minutes to form a resin layer having a thickness of 0.05 μm as the second layer 3. This baking makes the second layer 3 insoluble in the xylene solution described later.

As shown in FIG. 1C, an argon fluoride excimer laser beam 5 having a wavelength of 193 nm and a pulse width of 14 ns is used as an energy line for the second layer to form a desired pattern. Irradiate all at once
As a result, the laser light irradiation portion 3a of the second layer 3 was decomposed and removed. As a result, the minimum line width is 0.2 as shown in FIG.
A 5 μm pattern was formed. The laser light intensity at this time was 140 mJ / cm ² per pulse.

Next, on the surface of the pattern 3 of the second layer,
A xylene solution 6 containing an organosilicon resin having a weight molecular weight of about 10,000 and polystyrene having a weight average molecular weight of about 20,000 is poured. At this time, since surface tension acts as shown in FIG. 1E, the solution 6 can be laid flat except that the peripheral portion of the substrate 1 is slightly thinned.
Furthermore, this solution 6 solvent component (xylene) was added to the atmosphere at 25
Evaporated at ° C. Here, polystyrene has a high compatibility with the first layer, while the organosilicon resin has a high compatibility with the second layer. As a result, as shown in FIG. 1F, the polystyrene layer 8 is formed in the second layer removing portion 3a.
The organic silicon resin layer 7 is selectively deposited and grown on the layer remaining portion 3b, and the polystyrene layer 8 and the organic silicon resin layer 7 are completely phase-separated into a columnar pattern.

Thereafter, the layer 9 made of a mixture of polystyrene and an organic silicon resin, which remains on the entire surface of the deposited layers 7 and 8, is dissolved and removed by immersing the substrate to be treated in xylene for 30 seconds. (Fig. 1 (g)).

Then, as shown in FIG. 1 (h), the substrate to be processed was placed in a reaction vessel of a parallel plate type dry etching apparatus (not shown), and RIE (reactive ion etching) with oxygen gas was performed. Organic silicon resin layer 7
Was used as a mask, and the polystyrene layer 8 was etched together with the corresponding first layer thereunder, and a pattern having a minimum line width of 0.25 μm could be formed with high dimensional accuracy as shown in FIG. 1 (i).

Second Embodiment Next, a second embodiment of the pattern forming method according to the present invention will be described with reference to FIG.

First, a first layer 2'made of an aromatic polyimide resin having a weight average molecular weight of about 20,000 is formed as a flattening resin layer on the surface of the substrate 1 as shown in FIG. Formed by.

On the surface of the first layer 2 ', a resin layer, here a vinyl group as a functional group, is contained, and the weight average molecular weight is about 1.
After forming a second layer 3'of 5,000 organosilicon resin with a thickness of 0.03 μm as shown in FIG. 2 (b),
The entire surface of this second layer 3'was exposed to light from a 450 W mercury lamp for 40 seconds in a nitrogen atmosphere at 25 ° C. As a result, the second layer 3'becomes insoluble in the benzene solution described later.

Then, as shown in FIG.
The energy of the layer 3'of 248 nm,
The krypton fluoride excimer laser light 5'having a pulse width of 10 ns is collectively irradiated with a desired pattern through the photomask 4, whereby the laser light irradiation portion 3 of the second layer 3'is
By removing a, the pattern 3'having a minimum line width of 0.3 .mu.m was formed as shown in FIG.

Next, as shown in FIG. 2 (e), the substrate to be treated is treated with an organosilicon resin having a weight average molecular weight of about 10,000, polystyrene having a weight average molecular weight of about 17,000, and a weight average molecular weight of about 25. After immersing in a benzene solution containing 000 polymethylmethacrylate and placing this solution on the substrate to be treated, the solvent component of this solution was removed at 25 ° C. under reduced pressure. As a result, as shown in FIG. 2 (f), the organic silicon resin layer 7 was formed on the second layer residue 3b.
However, a layer 8'comprising a mixture of polystyrene and polymethylmethacrylate was selectively deposited and grown on the second layer removing portion 3a.

In the first embodiment, two kinds of resins are mixed in the solution, but in the second embodiment, three kinds of resins are mixed and the silicon resin is mixed with the second layer. Since the other two resins, namely polystyrene and polymethylmethacrylate, have high compatibility with the first layer, they selectively grow as described above.

After this, as in the above-described embodiment, the upper layer 9'of these deposited layers 7, 8'was removed (see FIG. 2).
(G)). Then, the substrate to be processed was subjected to reactive ion etching with oxygen gas as shown in FIG. 2 (h) as in the above-mentioned embodiment. A 3 μm pattern could be formed with high dimensional accuracy.

The present invention is not limited to the above embodiment. For example, in the above-mentioned embodiment, the high-energy ray is irradiated to form the pattern of the second layer so that the irradiated portion is directly decomposed and removed. It goes without saying that wet development may be used.

Further, as the high-energy rays for irradiation,
In addition to the excimer laser light of argon fluoride or krypton fluoride described above, continuous light of visible light or ultraviolet light, X-ray such as synchrotron radiation light, charged particle beam such as ion beam or electron beam can be used.

Further, in the above-mentioned embodiment, the second layer is insoluble in the solution, so that baking and whole surface exposure are performed on this layer, but the order of this step and the patterning step of the second layer is as follows. It doesn't matter which comes first.

Furthermore, in the above embodiments, the organic silicon resin was used as the material for the second layer, but any other material such as metal or metal may be used as long as it has resistance to dry etching by oxygen plasma. A semiconductor or an inorganic material such as an oxide or a nitride may be used. In this case, it may be formed on the first layer (resist layer), which is a lower layer, by a sputtering method or a CVD method at a low temperature so as not to affect the lower first layer, and patterned by etching. At the time of pattern processing, it may be decomposed and removed by energy rays, or may be patterned by a resist.

Since the surface of an inorganic material such as a metal, a semiconductor, an oxide or a nitride is generally hydrophilic, the material of the lower first layer is highly hydrophobic for imparting selectivity, that is, the whole. It suffices to use a material having a large proportion of hydrophobic groups in the. For example, a resin containing only carbon and hydrogen, such as polyethylene, propylene, or a rubber resin, or a resin containing fluorine, such as Teflon resin, may be used.

Further, as the etching in the last step, any etching can be used as long as a selective ratio can be obtained between the deposited layer on the second layer and the first layer and the deposited layer on this. May be. Furthermore, the invention can be appropriately modified and implemented without departing from the scope of the invention.

[0030]

According to the present invention, it is possible to form a pattern with high resolution by forming a deposited layer having different etching resistance in a pattern with high resolution and then etching.

[Brief description of drawings]

FIG. 1 is a process sectional view showing an embodiment of a pattern forming method according to the present invention.

FIG. 2 is a process sectional view showing another embodiment of the pattern forming method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate, 2, 2 '... 1st layer, 3, 3' ... 2nd layer 3a ... 2nd layer removal part, 3b ... 2nd layer remaining part, 4 ... Photomask, 5, 5 ' ... energy rays, 6,6 '... solution 7 ... layer deposited on second layer leaving section 3b, 8,8' ... layer deposited on second layer removal section 3a, 9,9 '... layer composed of mixture .

Claims (2)

[Claims] 1. A step of forming a first layer on a substrate, a step of patterning a second layer made of a material different from that of the first layer on the surface of the first layer, the first, A step of selectively growing layers of different materials on the surface of the second layer, and a growth layer formed on the pattern of the second layer as a mask and the growth layer on the first layer and the first layer And a step of etching the layer. 2. A step of forming a first layer on a substrate, and a step of patterning a second layer made of a material different from that of the first layer on the surface of the first layer, and then the step of forming the first layer. A step of bringing the surface of the substrate on which the first layer and the second layer are formed into contact with a solution containing plural kinds of resins of different materials to selectively grow different resin layers on the first and second layers, And a step of etching the resin layer grown on the first layer and the first layer using the resin layer grown on the second layer as a mask.