JPH10144586A - Semiconductor device and its fabrication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fine pattern reliably by forming a layer for rendering the resist insoluble on the interface between a resist and a work thereby preventing a resist pattern from collapsing. SOLUTION: A neutral layer 150 is formed of a basic substance on a semiconductor substrate 100. A chemically amplified resist 200 is then formed thereon and a specified part thereof is exposed. An acid is generated at a part 260 irradiated with a light and a reaction of the acid and a neutralization agent in the neutral layer 150 takes place in the vicinity of the surface of semiconductor substrate 100. Consequently, concentration of acid is lowered significantly and the acid is inactivated. The semiconductor substrate 100 is then immersed into a developer and the positive resist film 200 is shaped as specified. In this regard, the part close to the surface of the semiconductor substrate 100 is not dissolved even if the acid is deactivated and an insoluble layer 250 is left. According to the method, even a finely patterned positive resist film can be protected against collapsing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a resist pattern on a semiconductor substrate and a method for forming the same, and more particularly to a method for forming a fine resist pattern.

[0002]

2. Description of the Related Art The integration of integrated circuits (ICs) has increased by four years in three years.
It is increasing at twice the rate, and the miniaturization of elements is progressing year by year. For this reason, it is required that the element is formed on a substrate by a fine processing technique. In microfabrication technology, element isolation, electrodes, contact holes,
It is important to form a pattern of wiring and the like with high accuracy as desired, and a photoresist is used as a mask material for etching or ion implantation for forming the pattern. FIG. 1 shows a method of forming a resist pattern on a semiconductor substrate. As shown in FIG. 1A, a workpiece is deposited on a semiconductor substrate. next,
As shown in FIG. 1 (2), a resist (a polymer material having photosensitivity and dissolved in an organic solvent) is applied on a workpiece using a spin coating machine. During the application of the resist, prebaking is performed to volatilize the contained solvent. Next, as shown in FIG. 1C, a mask on which a circuit pattern is formed is superposed on a semiconductor substrate and exposed, and the pattern is transferred onto a resist. Next, as shown in FIG. 1D, a pattern is formed by immersion in a developer. The figure shows an example of a positive resist from which an exposed portion is removed. In the case where the resist is a negative resist, on the contrary, the exposed portion remains. After that, post-baking is performed to solidify the resist and improve etching resistance. Next, as shown in FIG. 1 (5), the workpiece is etched into a desired shape by performing etching using the patterned resist as a mask. Next, as shown in FIG. 1 (6), the resist is removed by ashing. Thus, typical process steps are completed. In addition, in a process mainly using an i-line stepper exposure apparatus, a positive resist having excellent resolution is generally used, and an alkaline aqueous solution (an organic alkali such as tetramethylammonium hydroxide or choline) is used as a developing solution. Used. As a resist used in a process mainly using a KrF stepper exposure apparatus, a chemically amplified resist has begun to be used.

[0003]

SUMMARY OF THE INVENTION In the above manner,
Fine patterns (especially quarter-micron patterns)
Is formed, the patterned resist is fine, so that the resist pattern is inclined or falls. this is,
It is considered that the resist pattern has a high aspect ratio, which is caused by the impact of a rinsing liquid during or after development and electrostatic force (stress) during wafer drying.

[0004] The present invention has been made in view of the above problems, and has as its object to provide a processing technique capable of forming a fine pattern without tilting or falling down and capable of coping with miniaturization of elements. And

[0005]

According to the present invention, in order to achieve the above object, a resist insolubilizing layer is formed on the sea surface of a resist and a workpiece when forming a chemically amplified resist pattern on the workpiece. Is formed. Since the present invention adopts the above configuration, a miniaturized pattern can be formed with high reliability without the resist pattern falling down.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to the drawings. As shown in FIG. 2A, a neutralization layer 150 is formed on the semiconductor substrate 100.
The neutralization layer 150 is formed of a basic substance, for example, an amine-based substance. Also, as shown in FIG.
A chemically amplified positive resist 200 is formed on the neutralizing layer 150, and a predetermined portion is exposed. In the chemically amplified positive resist, a resin and a photoacid generator (a substance having a catalytic action) that generates an acid (hydrogen ion) when exposed to light are mixed. For this reason, as shown in FIG. 2B, an acid is generated in a portion 260 of the chemically amplified positive resist 200 that is exposed to light. Next, as shown in FIG.
When the semiconductor substrate 100 or the like is subjected to a heat treatment, the acid (hydrogen ion) generated by the light and the neutralizing agent (here, Ammonia) undergoes a neutralization reaction, so that the concentration of acid (hydrogen ion) on the surface of the semiconductor substrate 100 is significantly reduced, and the acid (hydrogen ion) is deactivated. However, in other portions of the light-exposed portion 260,
The acid reacts with the resin in the positive resist film 200 without decreasing the acid concentration (see FIG. 3). Next, as shown in FIG. 3B, the positive resist film 200 is processed into a predetermined shape by immersing the positive resist film 200 in a developing solution. Here, it should be noted that, in the portion of the light-exposed portion 260 where the resin and the acid have reacted, the resin and the acid are easily dissolved in the developing solution. In the portion that has been significantly reduced, it does not dissolve even when immersed in the developing solution, and the insolubilized layer 250 remains. In the above embodiment, the amine-based substance is used as the neutralizing agent, but it goes without saying that the present invention is not limited to this as long as it is a basic substance.
Further, in the above description, the semiconductor substrate 100 is described as the workpiece, but is not limited to this. According to the present invention, since the insolubilized layer 250 remains at the base of the processed positive resist film 200,
Even if the processing dimension of 0 is made fine, the processed positive resist film 200 does not fall down. Therefore, a fine semiconductor element can be processed. Usually, when an impurity is implanted into a semiconductor substrate, the impurity is not implanted directly into the semiconductor substrate but through a buffer film such as an oxide film. However, when the positive resist film 200 processed as shown in FIG. 3 (2) is used as a mask for ion implantation, the insolubilized layer 250 also functions as a buffer film. There is no need to form an oxide film or the like to be used as a substrate. Further, as shown in FIG. 3B, the semiconductor substrate 100 is not exposed even after the processing of the positive resist film 200.
Also acts as a protective film on the surface of the semiconductor substrate 100.

Next, a second embodiment will be described in detail with reference to the drawings. In the first embodiment, a chemically amplified positive resist film is used. In this embodiment, an embodiment using a chemically amplified negative resist film will be described. As shown in FIG. 4A, an acid treatment layer 550 is formed on the semiconductor substrate 100. This acid treatment layer 550 is formed of an acidic substance. Further, as shown in FIG.
A chemically amplified negative resist 500 is formed on 50, and a predetermined portion is exposed. In the chemically amplified negative resist 500, a resin and a photoacid generator that generates an acid (hydrogen ion) when exposed to light are mixed. For this reason, acid is generated in the portion 560 where the chemical amplification type negative resist 500 is exposed to light (see FIG. 4 (2)). Next, the semiconductor substrate 1
When the heat treatment of 00 or the like is performed, the acid generated in the portion 560 exposed to light reacts with the resin contained in the negative resist 500. At this time, the acid contained in the acid treatment layer 550 and the resin contained in the negative resist 500 simultaneously react. In the portion where these resins and the acid have reacted, it becomes difficult to dissolve in the developer. Next, as shown in FIG.
By immersing 00 in a developing solution, it is processed into a predetermined shape.
It should be noted here that the portion where the acid and the resin have reacted as described above is difficult to dissolve in the developer,
The insolubilized layer 650 remains. In addition, the acid treatment layer is formed of an inorganic acid such as hydrogen halide, hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid, phosphoric acid, aromatic sulfonic acid, alkyl carboxylic acid,
Any organic acid such as an alkylsulfonic acid or an aromatic carboxylic acid can be used as long as it generates an acid group. Further, in the above description, the semiconductor substrate 100 is described as the workpiece, but is not limited to this. In the present invention, since the insolubilized layer 650 remains at the base of the processed negative resist film 500, the processed negative resist film 500 does not fall even if the processing size of the negative resist film 500 is reduced. Therefore, a fine semiconductor element can be processed. In addition, as described above, the insolubilized layer 650
Since it also functions as a buffer film, it is not necessary to form an oxide film or the like used as a buffer film as in the related art. Further, since the semiconductor substrate 100 is not exposed even after the processing of the negative resist film 500, the insolubilized layer 650 also functions as a protective film on the surface of the semiconductor substrate 100.

[0008]

According to the present invention, the above configuration is adopted.
A miniaturized pattern can be formed with high reliability without the resist pattern falling down.

[Brief description of the drawings]

FIG. 1 is a diagram showing conventional lithography and process steps.

FIG. 2 is a view showing a process chart of a method of manufacturing a semiconductor device according to the first embodiment of the present invention;

FIG. 3 is a view showing a process chart of a method of manufacturing a semiconductor device according to the first embodiment of the present invention;

FIG. 4 is a view showing a process chart of a method of manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 5 is a view showing a process chart of a method of manufacturing a semiconductor device according to a second embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 100 semiconductor substrate 150 neutralizing layer 200 chemically amplified positive resist 650, 250 insolubilized layer 500 chemically amplified negative resist 550 acid treatment layer 260, 560 part exposed to light

Claims (13)

[Claims] An object comprising: a workpiece; and a resist formed on the workpiece and patterned in a predetermined shape, wherein the resist patterned in a predetermined shape comprises:
A semiconductor device, characterized in that a resist remains at the bottom of a portion removed by immersion in a developing solution, and the resist is processed so that the workpiece is not exposed. 2. A method according to claim 1, further comprising a workpiece, and a resist formed on the workpiece, wherein the resist is immersed in a developing solution at a bottom of a portion to be removed by immersing the developing solution. A semiconductor device having an insolubilized layer that is not removed. 3. The semiconductor device according to claim 1, wherein the workpiece is a semiconductor substrate. 4. The semiconductor device according to claim 1, wherein said resist is a chemically amplified resist. 5. A neutralizing layer forming step for forming a neutralizing layer containing a neutralizing substance on a workpiece, and a light which generates an acid when a resin and light hit the neutralizing layer. A resist film forming step for forming a chemically amplified positive resist film containing an acid generator, and by exposing a predetermined portion of the chemically amplified positive resist film to within the chemically amplified positive resist film, A photo-acid generating step for generating an acid, the exposed predetermined portion of the chemically amplified positive resist film, and a deactivating step for deactivating the acid at a boundary between the neutralized layer, A method of manufacturing a semiconductor device, comprising: at least immersing the chemically amplified positive resist in a developer and processing the chemically amplified positive resist film into a desired shape. 6. A neutralizing layer forming step for forming a neutralizing layer containing a neutralizing substance on a workpiece, and a chemical amplification containing a catalytic action generating substance and a resin on the neutralizing layer. A resist film forming step for forming a mold positive resist film, an exposure step for exposing a predetermined portion of the chemically amplified positive resist film, and applying heat to at least the chemically amplified positive resist film, Reacting a substance having a catalytic action with the resin in the chemically amplified positive resist film, and reacting with a neutralizing substance contained in the neutralizing layer, at least the resist And dipping the resist film in a developer to process the resist film into a desired shape. 7. A neutralizing layer forming step for forming a neutralizing layer containing a neutralizing substance on a workpiece, and a light which generates an acid when a resin and light hit the neutralizing layer. A resist film forming step for forming a chemically amplified positive resist film containing an acid generator, and by exposing a predetermined portion of the chemically amplified positive resist film to within the chemically amplified positive resist film, A photoacid generation step for generating an acid, and applying heat to at least the chemically amplified positive resist film to cause a chemical reaction of the acid with the resin in the chemically amplified resist film, thereby dissolving the resin. A reaction step for neutralizing the acid generated by light and the neutralizing substance contained in the neutralizing layer, and
A method of manufacturing a semiconductor device, comprising: at least immersing the chemically amplified positive resist in a developer and processing the chemically amplified positive resist film into a desired shape. 8. The method according to claim 5, wherein the neutralizing layer formed in the neutralizing layer forming step contains a basic substance. 9. The method according to claim 5, wherein the neutralization reaction in the reaction step occurs on the surface of the workpiece.
8. The method for manufacturing a semiconductor device according to any one of claims 7 to 7. 10. An acid treatment layer forming step for forming an acid treatment layer containing an acidic substance on a workpiece, and a chemical amplification type containing a catalytic action generating substance and a resin on the acid treatment layer. A resist film forming step for forming a negative resist film, an exposure step for exposing a predetermined portion of the chemical amplification type negative resist film, and applying heat to at least the chemical amplification type negative resist film to form a catalyst. To cause a substance having an action to react with the resin in the chemically amplified negative resist film, and to cause an acidic substance contained in the acid treatment layer to react with the resin in the chemically amplified negative resist film. And a resist film processing step of immersing at least the chemically amplified negative resist in a developing solution and processing the chemically amplified negative resist film into a desired shape. Method of manufacturing location. 11. An acid treatment layer forming step for forming an acid treatment layer containing an acidic substance on a workpiece, and a photoacid which generates an acid when a resin and light shine on the acid treatment layer. A resist film forming step for forming a chemically amplified negative resist film containing a generating agent, and exposure of a predetermined portion of the chemically amplified negative resist film to form an acid in the chemically amplified negative resist film. Generating a photo acid, and applying heat to at least the chemically amplified negative resist film to cause a chemical reaction between the acid and the resin in the chemically amplified negative resist film, and acid treatment A reaction step for changing the solubility of the resin by causing a chemical reaction between the acidic substance contained in the layer and the resin, and immersing at least the chemically amplified negative resist in a developing solution, Shape the membrane as desired The method of manufacturing a semiconductor device comprising: the resist film processing step for machining, characterized in that is provided with a to. 12. The method according to claim 10, wherein the acidic substance is an inorganic acid. 13. The method according to claim 10, wherein the acidic substance is an organic acid.