JP3653960B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device, and to a method for forming a polyimide pattern.
[0002]
[Prior art]
Conventionally, polyimide has been used for an insulating passivation film of a semiconductor device or for other purposes.
12 to 17 are manufacturing process sectional views showing a conventional method of forming a polyimide pattern in the order of manufacturing processes.
[0003]
First, a polyimide film 2 having a uniform film thickness is formed on a semiconductor substrate 1 using a spin coater that is a spin coater (FIG. 12). Next, a positive photoresist film 3 is applied onto the polyimide film 2 by a spin coater (FIG. 13). Further, the photoresist film 3 is exposed 7 through the photomask 4 (FIG. 14). The photomask 4 is formed by patterning a portion that transmits light and a portion that does not transmit light on a glass plate. Next, a pattern of the polyimide film 2 is formed with an alkaline developer 5, and the semiconductor substrate 1 is covered with the patterned photomask 3a and the patterned polyimide film 2a (FIGS. 15 and 16). At this time, the photoresist film 3a is formed on the polyimide film 2a, and conventionally, the photoresist film 3a is removed immediately after development with an organic solvent such as acetone in order to remove the photoresist 3a (FIG. 17).
[0004]
[Problems to be solved by the invention]
However, in the conventional method, cracks occur in the polyimide film or a residue of the photoresist film occurs when the photoresist film is removed with an organic solvent in a portion where the polyimide pattern is fine or where the step of the base is large. That happened.
[0005]
An object of the present invention is to solve this problem and to provide a method for manufacturing a semiconductor device as a method for forming a polyimide pattern in which cracks do not occur and a photoresist film residue does not occur.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in a method of manufacturing a semiconductor device in which a polyimide film is selectively formed on a semiconductor substrate, a step of applying polyimide on the semiconductor substrate and drying, and a photoresist film on the polyimide forming, a step of exposing through a photomask patterned the photoresist film, by selectively removing the developer and the polyimide of the photoresist film, the photo that has been patterned on the semiconductor substrate forming a resist film and the polyimide, a semiconductor substrate having a photoresist film and a polyimide which is the patterned, and a step of standing to 20 minutes to at 80 ° C. to not 40 ° C. 1000 minutes, removing the photoresist film A manufacturing method including a process.
[0007]
As described above, after the development, before removing the photoresist film, the semiconductor substrate covered with the photoresist film and the polyimide film is allowed to stand for a predetermined temperature and for a predetermined time, so that Rather than removing the resist film, the occurrence rate of cracks in the polyimide film can be reduced, and the residue of the photoresist film (the photoresist film cannot be removed and part of the photoresist film remains) can be eliminated. Therefore, by optimizing the standing temperature and time, it is possible to form a polyimide pattern free from cracks and free from photoresist film residue.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 are manufacturing process cross-sectional views illustrating the manufacturing process for forming a polyimide film according to the first embodiment of the present invention in the order of the processes. This polyimide film functions as a surface protective film and an insulating film of the semiconductor element.
First, polyimide is applied to a semiconductor substrate 1 called a semiconductor wafer, on which a semiconductor element such as an insulated gate bipolar transistor (IGBT) is formed, by a spin coater that is a spin coater, and baked at 130 ° C. for 30 minutes. For example, a polyimide film 2 having a thickness of about 9 μm is formed (FIG. 1). Next, a positive type photoresist is applied by a spin coater and baked at 95 ° C. to form a photoresist film 3 having a thickness of about 3 μm, for example (FIG. 2). Next, exposure 7 is performed through a patterned photomask 4 to form a polyimide pattern (a pattern in which an external lead-out terminal portion or the like is opened) (FIG. 3). Thereafter, the semiconductor substrate 1 covered with the photoresist film 3 and the polyimide film 2 is immersed in the developer 5 in the developer tank 8 for a predetermined time, and the development of the photoresist film 3 and the etching of the polyimide film 2 are performed simultaneously. Then, a patterned polyimide film 2a and a patterned photoresist film 3a are formed on the semiconductor substrate 1 (FIG. 4). Then, rinse with pure water (washing) and dry (FIG. 5). Next, before removing the photoresist film 3a, the semiconductor substrate 1 covered with the photoresist film 3a and the polyimide film 2a is placed in the thermostatic chamber 6 and left at a predetermined temperature for a predetermined time (FIG. 6). ). Of course, the standing temperature and the standing time are controlled temperature and time.
[0009]
Next, the photoresist film 3a is removed with an organic solvent (for example, acetone) (FIG. 7). It has been proved by experiments that the predetermined standing temperature is 40 ° C. to 80 ° C. and the standing time is preferably in the range of 20 minutes to 1000 minutes. Next, the contents of this experiment will be described. The production conditions of the polyimide pattern are an example, and the polyimide pattern used in this experiment has a pattern width of several μm to several hundred μm and a step of several μm to several tens of μm.
[Experimental Example 1]
FIG. 8 is a diagram showing the standing temperature and the crack generation rate when the standing time is 120 minutes, and FIG. 9 is the standing temperature and resist residue (residue of the photoresist film) when the same standing time is used. It is the figure which showed the incidence rate.
[0010]
In FIG. 8, cracks are likely to occur when the standing temperature is low, and cracks are difficult to occur when the standing temperature is high. On the other hand, in FIG. 9, the ratio of the photoresist film remaining without being removed at the time of removing the photoresist film, that is, the generation rate of the resist residue, hardly occurs when the standing temperature is low, but occurs when the standing temperature is high. It becomes easy. Analyzing the experimental results from the two viewpoints of the occurrence of cracks in the polyimide film and the residue of the photoresist film, 40 ° C. to 80 ° C. is suitable as the standing temperature when the standing time is 120 minutes.
[Experimental example 2]
FIG. 10 is a diagram showing the standing time and crack generation rate when the standing temperature is 55 ° C., and FIG. 11 is a diagram showing the resist residue generation rate when the same standing temperature is used.
[0011]
In FIG. 10, if the standing time is short, cracks are likely to occur, and if the standing time is long, cracks are difficult to occur. On the other hand, in FIG. 11, the residue of the photoresist film hardly occurs when the standing time is short, and easily occurs when the standing time is long. From the two viewpoints of generation of cracks and residue of the photoresist film, the standing time when the leaving temperature is 55 ° C. is suitably 20 minutes to 1000 minutes.
[0012]
Further, from another experiment, in the combination where the standing temperature is in the range of 40 ° C. to 80 ° C. and the standing time is in the range of 20 minutes to 1000 minutes, the occurrence of cracks is extremely small and the generation of the residue of the photoresist film is extremely small. It was found that a good polyimide pattern can be formed.
[0013]
【The invention's effect】
According to the present invention, the semiconductor substrate covered with the photoresist film and the polyimide film is left at a predetermined temperature for a predetermined time, and then the photoresist film is removed, thereby removing the photoresist film. Cracks can be prevented from occurring in the polyimide film, and the remainder of the photoresist film is not generated, and a good polyimide pattern can be formed.
[Brief description of the drawings]
FIG. 1 is a sectional view of a manufacturing process for forming a polyimide film according to a first embodiment of the present invention. FIG. 2 is a sectional view of a manufacturing process for forming a polyimide film following FIG. 1 of the first embodiment of the present invention. 3 is a sectional view of a manufacturing process for forming a polyimide film following FIG. 2 of the first embodiment of the present invention. FIG. 4 is a sectional view of a manufacturing process for forming a polyimide film following FIG. 3 of the first embodiment of the present invention. 5 is a sectional view of a manufacturing process for forming a polyimide film following FIG. 4 of the first embodiment of the present invention. FIG. 6 is a manufacturing process for forming a polyimide film following FIG. 5 of the first embodiment of the present invention. FIG. 7 is a cross-sectional view of a manufacturing process for forming a polyimide film following FIG. 6 of the first embodiment of the present invention. FIG. 8 shows a standing temperature and a crack generation rate when the standing time is 120 minutes. [Figure 9] Standing temperature and resist residue when the standing time is 120 minutes Fig. 10 is a diagram showing the standing time and crack generation rate when the standing temperature is 55 ° C. Fig. 11 is a standing time and generation of resist residues when the standing temperature is 55 ° C. FIG. 12 is a cross-sectional view of a manufacturing process for forming a conventional polyimide pattern. FIG. 13 is a cross-sectional view of a manufacturing process following FIG. 12 for forming a conventional polyimide pattern. FIG. 15 is a cross-sectional view of a manufacturing process following FIG. 14 for forming a conventional polyimide pattern. FIG. 16 is a cross-sectional view of a manufacturing process following FIG. 15 for forming a conventional polyimide pattern. FIG. 17 is a sectional view of a manufacturing process following FIG. 16 for forming a conventional polyimide pattern.
DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Polyimide film 2a Polyimide film 3 Photoresist film 3a Photoresist film 4 Photomask 5 Developer 6 Constant temperature bath 7 Exposure 8 Developer tank

Claims (1)

In a manufacturing method of a semiconductor device in which a polyimide film is selectively formed on a semiconductor substrate, a step of applying polyimide on the semiconductor substrate and drying, a step of forming a photoresist film on the polyimide, and the photoresist film a step of exposing through a patterned photomask, the photoresist film development and the polyimide is selectively removed in the step of forming a photoresist film and the polyimide is patterned on the semiconductor substrate And a step of leaving the patterned photoresist film and polyimide-containing semiconductor substrate at 40 ° C. to 80 ° C. for 20 minutes to 1000 minutes, and a step of removing the photoresist film. A method for manufacturing a semiconductor device.

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