JPS5914550B2 - Microfabrication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for finely processing a metal film, an oxide film, or the like using a photoetching process.

Conventionally, when microfabricating a metal film, oxide film, etc., a photo-etching method is generally used to form a desired pattern with a photoresist film on the metal film, oxide film, etc. on the substrate 5. Alternatively, a method may be used in which the oxide film is etched with an etchant such as an acid or alkaline solution, the photoresist film is peeled off, and a desired metal film or oxide film pattern is formed on the substrate. It is being

Here, FIG. 1 shows a striped pattern 2 of a metal film or oxide film divided into two parts in a comb shape provided on a substrate 1 as a desired pattern, and the width of each of these 15 stripes is about 10. μm, and if the gap between each stripe is several μm, it is extremely difficult to completely divide each stripe into two parts without any disconnection.

Figure 2 shows 20 types of defects that occur when trying to obtain these patterns. In part A, a short circuit occurs between both comb-shaped stripes, and in part B, a short circuit occurs between the stripes. A disconnection has occurred. It is not easy to completely eliminate the above-mentioned defects when producing fine patterns using photoetching. Furthermore, the larger the area, the more serious these problems become. The causes of these defects include the quality of the metal film or oxide film, scratches on the photomask when forming the photoresist film pattern used as a mask, adhesion of dust, and contamination of dust in the photoresist film itself. As a result, it is nearly impossible to eliminate all of these. Therefore, the present invention relates to a manufacturing method that allows a completely good pattern to be obtained in the end even if these causes occur. First, as a method for preventing disconnection of the stripe pattern 35, a photoresist film pattern is used. A short circuit in the stripe pattern can be achieved by forming the photoresist pattern in two layers, and after etching the metal layer or etching the oxide film, the photoresist film is removed. Then, a photoresist film pattern is formed twice on the metal film or oxide film stripe pattern to prevent disconnection.
A method in which a metal film or an oxide film is etched, and short circuits in the stripes caused by the first etching are corrected by the second etching, thereby forming a stripe pattern without disconnections or short circuits. It is. According to this method, for example, even if a defect occurs in the photomask when forming a photoresist film pattern, or even if dust adheres to or mixes in the photoresist film or the photomask, a good pattern can be formed. This has a great effect on production. Next, the processing method of the present invention will be explained as a first embodiment using the manufacturing process structure diagrams 1 to 1 in FIG. 3.

First, as shown in FIG. 3A, a metal film or oxide film 2 is formed on a substrate 1 (for example, silicon) by vacuum evaporation or CVD, and then a photoresist film pattern 3 is formed on this. do.

At this time, the photoresist film forms a pattern for making the metal film or oxide film 2 into stripes. Parts A and B show defects when the photoresist film pattern was formed. Part A shows a state in which the photoresist film pattern is not formed in a stripe shape and is shorted to each other, and part B shows a state in which the photoresist film pattern is not formed in a stripe shape. Indicates that the wire has not been delivered and the wire is disconnected. Next, as shown in the opening of FIG. 3, a photoresist film pattern is again formed on the same portion of the photoresist film where the defect has occurred. At this time, if the same photomask for forming the photoresist film pattern 4 is used for forming the photoresist film pattern 3 for the 11th time, shift the photoresist film pattern 4 by n pitches (n is a positive integer) and use the photoresist film for the second time. Form pattern 4. By this method, defects occurring in the photomask will not occur in the same portion as the photoresist film pattern. Here, a second photoresist film pattern 4 is formed on the disconnection defect B portion of the first photoresist film pattern 3 so as to prevent the disconnection. Note that, at this point, the short-circuit defect portion A has not been improved. Next, as shown in FIG. 3C, using the photoresist film patterns 3 and 4 as protective films, the metal film or oxide film 2 is etched with an acid or alkaline etching solution. At this time, any etching method may be used. Next, as shown in FIG. 2, the photoresist film patterns 3 and 4 are removed from the metal film or oxide film 2 using an acid or an organic solvent. Here, the metal film or oxide film 2 is formed in a predetermined pattern,
A stripe pattern with short circuits but no disconnections is formed. Next, in order to eliminate short circuits, a photoresist film pattern 3 is applied again to the metal film or oxide film 2 formed as a stripe pattern on the substrate 1, as shown in E.
form. At this time, in order to prevent short-circuit defects caused by the photomask from being formed in the same part, the previous pattern is
They are formed by shifting the pitch (n is a positive integer). At this time, it is assumed that a short circuit portion C1 and a disconnection portion B occur as defects in the photoresist film. Next, in order to prevent the disconnection part B as shown in FIG. At this time, in order to prevent the same defect from occurring in the same part, the relative position with respect to the photoresist film pattern 3 is set at n pitches (n is a positive integer), similarly to the method described above.
Shift and form. As a result, the disconnection defect B portion is protected by the photoresist film pattern 4. Next, as shown in the figure, the metal film or oxide 2 is etched again with the respective acid or alkaline solution. Next, as shown in FIG. A pattern can be formed. According to this method, a photoresist film pattern is formed twice to prevent wire breakage, and a perfectly good pattern is produced by forming two photoresist films with different defective areas and etching twice to prevent short circuits. It is. If the cause of the short circuit or disconnection defect is in the photomask,
The first and second Hohe resist patterns are
They are formed at different pitches (n is a positive integer) to prevent defects of both patterns from being formed in the same part. Next, another embodiment will be described using FIG. 4. First, the substrate 1 shown in FIG.
As shown in the opening of FIG. 4, an object to be etched 12 made of a metal film or an oxide film to be processed is formed on the etching material 1. As shown in FIG. Next, as shown in FIG.
is uniformly formed to a thickness of about 0.2 to 1.01 tm.
Next, as shown in FIG. 4-2, a photomask 14 is placed on the photoresist film 13, and a first baking process is performed using ultraviolet rays. After the photoresist film 13 has been printed with a pattern using a photomask 14, it is subjected to predetermined treatments such as development and heat treatment, and as shown in FIG. Formation is complete. However, in this state, there is a probability that some parts of the object to be etched 12 will be etched unnecessarily due to pinholes occurring in the photoresist film 13, dust adhering to the photomask, and defects in the photomask. occurs. In particular, in the case of a single pattern over a large area, the single defect may cause the single substrate to become defective. Therefore,
As shown in FIG. 4, a photoresist film 15 is further coated on the photoresist film 13 completed in FIG. 4E by the method described above. Next, as shown in Figure 4,
Using the same photomask 14 used for the first pattern baking, the photoresist film 15 is pattern-exposed to ultraviolet light again in alignment with the photoresist pattern 13 formed the first time. At this time, the photomask 14 and the first photoresist pattern 13 are aligned in the first exposure in order to prevent defects occurring in the photomask 14 from occurring at the same location during the second exposure. The photomask 14 is shifted from the photoresist pattern 13 by n pitches (n is a positive integer), and a second exposure is performed. Next, the second photoresist film is again subjected to the predetermined steps of development and heating to form a second photoresist pattern 15 on the first photoresist pattern 13. Next, the object to be etched 12 is etched using a predetermined etching solution using these two photoresist films as a protective film, and after finishing, the photoresist film is removed from the substrate as shown in FIG. Therefore, fine processing of the object to be etched can be performed. However, in this state, the photoresist patterns formed in the first and second processes do not have any defective parts where the object to be etched is unnecessarily etched; Defects that remain may occur. Therefore, the manufacturing process from FIG. 4 C onwards is repeated again. At this time, the first photoresist pattern 13 formed during the first etching
The positions of the second photoresist pattern 15, the third photoresist pattern and the fourth photoresist pattern formed during the second etching are further n
By shifting the pitch (n is a positive integer), unnecessary etching objects will not remain in the same part during the second etching. As described above, the present invention can use the same mask to eliminate defects in photomasks that have defects or defects that occur during manufacturing, and since the same mask can be used, This is advantageous in terms of dimensional accuracy and cost.

In this way, in the present invention, when microfabricating a metal film or an oxide film, if the pattern is striped,
Open circuit defects are protected by a double photoresist film pattern, and short circuit defects are completely eliminated by forming the pattern twice and etching twice, which has great effects in terms of yield and manufacturing.

Although the present invention has been described with respect to a stripe pattern, the present invention can also be applied to general IC manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a good stripe pattern, FIG. 2 is a plan view of a stripe pattern when a defect occurs, and FIGS.
FIGS. 4A to 4E are sectional views sequentially showing other embodiments of the present invention. 1, 11... Substrate, 2, 12... Metal film or oxide film, 3, 4, 13, 15... Photoresist film, 1
4...Photomask.

Claims (1)

[Claims] 1. A photoresist film is provided on the surface of the layer to be etched on the substrate surface, the photoresist film is irradiated with light through a photomask, unnecessary parts of the photoresist film are removed, and a first stripe-shaped photoresist film is formed on the surface of the layer to be etched. After forming an etching mask, a photoresist film is again provided on the surface of the first etching mask, and the photomask is the same as that used when forming the first etching mask, with an n pitch (n is a positive integer). 1. A microfabrication method comprising at least one step of: (1) irradiating light in a staggered manner, forming a second etching mask on the first etching mask, and then etching.