JP3225676B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a semiconductor device.
(In this specification, these are collectively referred to simply as “semiconductor
Device. " The present invention particularly relates to a method for dry etching an interlayer insulating film made of an organic resin film such as a polyimide resin film.

[0002]

2. Description of the Related Art As a fine processing method of a polyimide resin film, a method using a hydrazine-based etchant after the polyimide resin film is completely cured, a method in which wet etching is performed simultaneously with the development of an upper-layer photoresist during semi-curing, and a method in which dry etching is performed after complete curing. There are four types, one that performs the patterning, and a method that imparts photosensitivity to the polyimide resin and performs patterning like a normal photoresist. But 2-3 μm
In order to obtain the following pattern dimensions, dry etching is desirable in terms of accuracy. In the case of dry etching, the main component of the gas used is oxygen. In this case, it is more advantageous for the etching mask on the polyimide resin to have resistance to oxygen plasma in terms of patterning.
As described in the monthly publication on page 46, a metal thin film such as a Mo thin film is used as an etching mask of a polyimide resin.

[0003]

When the aspect ratio of the contact hole opened in the polyimide resin is large, the upper layer wiring is less likely to be disconnected if the contact hole has a forward taper. However, when dry etching is performed and a non-receding mask such as a metal thin film is used, the cross-sectional shape exhibits a vertical or overhang shape. Therefore, the upper layer wiring is easily broken.

Accordingly, it is desirable to give a forward taper to the contact shape while performing dry etching.
For this purpose, a material that recedes during etching, such as a photoresist, must be selected as an etching mask. By the way, the detection of the etching end point of an organic thin film such as a polyimide resin usually uses the intensity change of CO plasma emission,
If an organic thin film is used as an etching mask like a photoresist, this detection method is difficult to use.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for producing silicon or silicon.
Is a method of manufacturing a semiconductor device having an interlayer insulating film made of an organic resin on a substrate having a silicon oxide film , wherein a step of forming an interlayer insulating film on the substrate and curing the substrate; The step of forming an etching mask and the dry etching of the interlayer insulating film are performed by plasma using a mixed gas of a chlorofluorocarbon-based gas and oxygen, and the end point of the dry etching of the interlayer insulating film is detected by plasma emission of SiF ₄ or SiF. Monitoring and plasma emission intensity of the SiF ₄ or SiF.
Based on the end point detection of dry etching
It characterized by having a step of etching the interlayer insulating film by oxygen gas by stopping the supply of the feeder the flon gas.

According to the present invention, there is provided a method of manufacturing a semiconductor device having an interlayer insulating film made of an organic resin containing nitrogen such as a polyimide resin on a substrate, comprising the steps of: forming the interlayer insulating film on the substrate; Using an orthodiazonaphthoquinone-novolak resin-based photoresist as an etching mask for an interlayer insulating film, a step of sequentially applying, prebaking, exposing, and developing the photoresist, and a step of performing postbaking after exposing the photoresist entirely. And dry etching the interlayer insulating film using oxygen gas, and monitoring the end point of the dry etching of the interlayer insulating film by plasma emission of NO.

[0007]

[0008]

[0009]

EXAMPLES (Example 1) Polycrystalline silicon is deposited on a glass substrate 101 at a thickness of 1000 Å, and is patterned into a predetermined shape to obtain a lower wiring 102. After this, the interlayer insulating film 1
As 03, for example, a polyimide resin such as RN812 manufactured by Nissan Chemical Co., Ltd. is applied so as to have a thickness of about 2 μm, and the resin is fired in a nitrogen atmosphere at 300 ° C. using an oven. Next, a photoresist 104 having a thickness of about 3 μm is formed and used as an etching mask for the interlayer insulating film 103.
Reactive ion etching (hereinafter referred to as RIE) was used as dry etching for etching the interlayer insulating film 103. Etching is 50mTorr, RF input is 193mW / c
m ² , CHF ₃ gas flow rate 1 sccm, O ₂ gas flow rate 20 sccm. The end point of the etching of the interlayer insulating film 103 was detected by observing a change in the intensity of SiF ₄ plasma emission during this etching. When the lower wiring 102 under the portion to be etched of the interlayer insulating film 103 is exposed, the SiF
_{4 Although the} plasma emission intensity increases, CHF ₃
The supply of gas was stopped, and overetching was performed using only O ₂ gas. After the etching is completed, the photoresist 104 is stripped with a stripping solution, and the process of processing the interlayer insulating film 103 is completed.

According to the above embodiment, the interlayer insulating film 103 is
In addition to being able to perform accelerated etching by adding elements, when the underlying film of the portion to be etched of the interlayer insulating film 103 is a silicon-containing film such as polycrystalline silicon or silicon oxide, the etching end point is detected by observing the emission of SiF ₄ plasma. Became possible. Therefore, the supply of the CFC-based gas can be stopped at the same time as the lower wiring is exposed, and the lower wiring becomes CHF _3.
Even if the material is etched by a chlorofluorocarbon gas, the progress of etching of the lower wiring can be prevented.

At the same time, since the photoresist can be used as an etching mask, it is possible to give a forward taper to the shape of the contact hole.

In this embodiment, S is used for detecting the etching end point.
Although the example using iF ₄ plasma light emission was shown, SiF plasma light emission could also be used.

(Example 2) Polycrystalline silicon is deposited on a glass substrate 201 at a thickness of 1000 、, and is patterned into a predetermined shape to obtain a lower wiring 202. Thereafter, as the interlayer insulating film 203, for example, a polyimide resin such as RN812 manufactured by Nissan Chemical Co. is applied so as to have a thickness of about 2 μm,
The resin is fired in a nitrogen atmosphere at 300 ° C. using an oven. Next, a novolak resin-based photoresist 204 using orthodiazonaphthoquinone as a photosensitive group such as TSMR8700 manufactured by Tokyo Ohka Co., Ltd. is sequentially coated, prebaked, exposed, and developed to a thickness of about 3 μm.
Thereafter, the entire surface of the photoresist 204 is exposed,
Post-baking is performed in an air atmosphere at 1 ° C. for 1 hour to obtain an etching mask. R is used for etching the interlayer insulating film 203.
The IE method was used. Etching was performed at 50 mTorr, RF input of 193 mW / cm ² , and O ₂ gas flow rate of 20 sccm. The end point of the etching of the interlayer insulating film 203 was detected by observing the change in the intensity of the NO plasma emission at a wavelength of 2560 ° during this etching. After the etching was completed, the remaining photoresist 204 was stripped with a stripping solution, and the processing step of the interlayer insulating film 203 was completed.

The reason why the entire surface of the photoresist is exposed in the examples is that N ₂ is released from the photosensitive group orthodiazonaphthoquinone in the photoresist by light irradiation. Photoresist 204 as an etching mask
When the N element is released from the substrate, a NO plasma emission signal due to the N element in the interlayer insulating film clearly appears, so that the end point of the interlayer insulating film 203 can be easily detected. At the same time, since the photoresist can be used as an etching mask, a forward taper angle can be given to the contact hole shape of the interlayer insulating film 203.

[0015]

According to the present invention, it is possible to use a photoresist that recedes during etching as an etching mask for an interlayer insulating film using an organic resin such as a polyimide resin. Can be provided with a forward taper angle. In addition, the present invention
More interlayer insulating film using organic resin such as polyimide resin
The underlying silicon or silicon oxide
Without using an organic resin such as polyimide resin
Quick, complete and reliable etching of insulating films
it can.

Further, a step of providing a metal thin film serving as an etching mask on the interlayer insulating film, a step of patterning the metal thin film, and a step of peeling the metal thin film after the etching of the interlayer insulating film, which have been conventionally required. Can be omitted, so that the process can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a process described in a first embodiment.

FIG. 2 is a cross-sectional view illustrating a process described in a second embodiment.

FIG. 3 is a cross-sectional view illustrating a process of a conventional example.

[Explanation of symbols]

 101, 201, 301 Glass substrate 102, 202, 302 Lower wiring 103, 203, 303 Interlayer insulating film 104, 204, 304 Photoresist 305 Metal thin film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/3065 H01L 21/768

Claims (2)

(57) [Claims] 1. It has a silicon or silicon oxide film.
In a method of manufacturing a semiconductor device having an interlayer insulating film made of an organic resin on a substrate, a step of forming and curing an interlayer insulating film on the substrate,
Forming an etching mask with a photoresist on the interlayer insulating film, and performing dry etching of the interlayer insulating film by plasma using a mixed gas of a chlorofluorocarbon-based gas and oxygen, and detecting an end point of the dry etching of the interlayer insulating film. Monitoring by plasma emission of SiF ₄ or SiF, and plasma emission of SiF ₄ or SiF
Based on end point detection of dry etching by detecting increase in intensity
The method of manufacturing a semiconductor device characterized by comprising the step of Hazuki etching the interlayer insulating film by oxygen gas by stopping the supply of the flon gas. 2. A method of manufacturing a semiconductor device having an interlayer insulating film made of an organic resin containing nitrogen such as a polyimide resin on a substrate, comprising: forming the interlayer insulating film on the substrate and curing the film; Using an orthodiazonaphthoquinone-novolak resin-based photoresist as an etching mask for the film, coating the photoresist, pre-baking, exposing,
A step of sequentially performing development, a step of performing post-baking after exposing the entire surface of the photoresist, and a step of performing dry etching on the interlayer insulating film using oxygen gas, and detecting an end point of the dry etching of the interlayer insulating film at that time. Monitoring the semiconductor device with plasma emission of NO.