JPH11345874A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely remove the residuum of photoresist attached to the inner wall of a contact hole, by providing a process which forms an opening part at least in an insulating film, a process which cleans the opening part by plasma processing, and a process which cleans the opening part by a solvent. SOLUTION: With a resist film 103 as an etching mask, a contact hole C is formed in an interlayer insulating film 102 by reactive ion etching. A part of residuum 104 of photo resist is attached to the inner wall of the contact hole C, and the part is removed. The residuum removing process comprises 02 plasma processing and cleaning process. In the plasma processing, plasma is applied on the contact hole C, and the residuum material is oxidized so as to be readily removed. In the cleaning process, the residuum material is softened or dissolved by the process for immersing the entire substrate into the liquid- state separating agent and removed. Under the state, wherein the residuum 104 of the photoresist is perfectly removed, a conducting film 105 such as an A1 film is formed by a sputtering method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, in a method for manufacturing a semiconductor device such as an LSI or an active matrix substrate for a liquid crystal device, a process for forming a contact hole is as shown in FIG.

Here, FIG. 6 shows that a conductive layer 101 made of a p-Si (polysilicon) film is formed on the surface of a substrate 100 made of, for example, quartz glass or a silicon wafer, and SiO ₂ is formed thereon by CVD or the like. FIG. 6 shows a procedure for forming a contact hole reaching the conductive layer 101 in the interlayer insulating film 102 in a semiconductor device having an interlayer insulating film 102 made of (FIG. 6A).

[0004] First, a photoresist is applied on an interlayer insulating film 102 in which a contact hole is to be formed, and is then exposed to light to form a resist film 103 having an opening 103a as a contact hole pattern in a contact hole forming portion. Is formed (FIG. 6B).

Next, using the resist film 103 as an etching mask, reactive ion etching (R) using, for example, a mixed gas of CHF ₃ and SF ₆ as an etching gas.
A contact hole C is formed in the interlayer insulating film 102 made of SiO ₂ by anisotropic dry etching such as IE (Reactive Ion Etching) (FIG. 6C).

[0006]

However, FIG. 6 (b)
When the contact hole C is formed in the interlayer insulating film 102 by reactive ion etching in the step ( ₁ ), the reaction gas (CHF ₃ , SF ₆ ) is ionized to generate a chemically extremely active radical F *.

The radical F * collides with and reacts with the SiO ₂ film serving as the interlayer insulating film 102 to form a contact hole C, and also collides with the resist film 103 serving as an etching mask. Residue of photoresist 1 by combining with carbon (C) as
04 as a polytetrafluoroethylene-based substance (-C
F ₂ CF ₂ −) n is generated.

Then, the photoresist residue 104 is formed.
A part of the contact hole enters the contact hole C during the etching and adheres to the inner wall of the contact hole C (FIG. 6C). In particular, the polytetrafluoroethylene-based substance is extremely stable chemically and resistant to high temperatures as known by trade name Teflon, and has a strong adhesion to the inner wall of the contact hole C.

If an Al film or the like is formed as a conductive film 105 by sputtering or the like while the photoresist residue 104 made of the polytetrafluoroethylene-based substance is still attached to the contact hole C, the photoresist is removed. The Al film does not adhere to the inner wall of the contact hole C due to the influence of the residue 104, or a portion of the photoresist residue 104 protrudes from the conductive film 105 (a state as shown in FIG. Membrane 105
However, there is a problem that the semiconductor device is liable to be peeled off, thereby causing disconnection or the like, thereby lowering the reliability of the semiconductor device.

The present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to reliably remove a photoresist residue attached to an inner wall of a contact hole when forming the contact hole. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can be performed.

[0011]

To achieve the above object, a method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device having a switching element and an insulating film formed on a substrate, The method includes at least a step of forming an opening in the insulating film, a step of cleaning the opening by plasma treatment, and a step of cleaning the opening with a solvent.

According to this, since the opening is cleaned by the plasma treatment and the cleaning treatment with the solvent,
For example, a conductive film can be favorably formed in a contact hole, and the reliability of an active matrix substrate for a liquid crystal device or a semiconductor device such as an LSI can be improved.

It is characterized in that an etching mask is formed on the insulating film with a photoresist, and the opening is formed by dry-etching the insulating film with an etching gas.

[0014] In this case, the etching gas may be a fluorine-based gas, when the insulating film is formed of SiO ₂ film, formed efficiently contact holes reacts with the SiO ₂ film can do.

The residue of the photoresist contains a polytetrafluoroethylene-based substance formed by combining carbon atoms contained in the photoresist with fluorine atoms of a fluorine-based gas serving as the etching gas. In such a case, the photoresist residue containing the polytetrafluoroethylene-based substance can be effectively removed by plasma treatment and cleaning treatment with a solvent.

In the case where the dry etching is reactive ion etching using a fluorine-based gas,
Since the fluorine-based gas is ionized to generate radicals F *, when the insulating film is formed of a SiO ₂ film, the SiO ₂ film reacts with the radicals F * to form a contact hole efficiently. it can.

Further, by alternately performing the plasma processing and the cleaning processing a plurality of times, the photoresist residue can be reliably removed.

As the solvent, a mixture of sulfuric acid and hydrogen peroxide or an organic alkali-based release agent can be used.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration example of a liquid crystal panel to which an active matrix substrate AM using TFTs manufactured by applying the method of manufacturing a semiconductor device according to the present invention is applied.

As shown in FIG. 1, on an active matrix substrate (TFT array substrate) AM, a pixel region (actually, a liquid crystal layer 52) regulated by a plurality of pixel electrodes 52 is provided.
(A region of a liquid crystal panel on which an image is displayed due to a change in the alignment state), a sealing member 54 made of a photo-curable resin is provided along the pixel region as an example of a sealing member that surrounds the liquid crystal layer 53 by bonding the two substrates together. Have been. Then, the incident-side counter substrate 56 having the color filter layer 55
A light-shielding peripheral parting layer 57 is provided at a portion corresponding to the above-mentioned pixel region outside seal material 54 inside region.

When the active matrix substrate AM is set in a light-shielding case in which an opening is formed corresponding to a pixel region later, the peripheral parting layer 57 is formed in the pixel region due to a manufacturing error or the like. Formed of a band-shaped light-shielding material having a width of about 500 μm to 1 mm around the pixel area so as not to be hidden by the edge, that is, for example, to allow about several hundred μm as a shift of the liquid crystal panel substrate 50 from the case. Is done. Such a light-shielding peripheral parting layer 57 is made of, for example, Cr (chrome) or N
The counter substrate 31 is formed by sputtering, photolithography, and etching using a metal material such as i (nickel) and Al (aluminum). Instead of the metal material, the peripheral parting layer 57 may be formed of a material such as resin black in which carbon or Ti (titanium) is dispersed in a photoresist.

A peripheral circuit (scanning line drive circuit) 58 and a pad 59 as an external terminal are provided along the lower side of the pixel region in a region outside the sealing material 54, and are provided on both sides of the pixel region (two on the left and right in the figure). A peripheral circuit (signal line driving circuit) 60 is provided along the side. Further, a wiring 61 for electrically connecting the peripheral circuits 60 provided on both sides of the pixel region is provided on the upper side of the pixel region.
Further, columns 62 made of a conductive source voltage material for establishing electrical continuity between the active matrix substrate 51 and the counter substrate 56 are provided at the four corners of the sealing material 54. Then, a counter substrate 56 having substantially the same contour as the sealing material 54 is fixed to the active matrix substrate AM by the sealing material 54, and the liquid crystal panel P is formed.

The process of forming a contact hole in the present embodiment includes a transistor for turning on / off the pixel electrode 52 on the active matrix substrate AM, a transistor constituting the scanning line driving circuit 58, and a peripheral circuit (signal line driving circuit). The present invention can be applied to the case of forming any of the transistors and the like constituting 60).

FIG. 2 is a process chart showing an example of a contact hole forming process in the method of manufacturing a semiconductor device according to the present invention.

The semiconductor device manufactured through this process can be applied to an active matrix substrate for liquid crystal devices, an LSI, and the like as described above.

First, a p-Si film 101 as a conductive layer is formed on the surface of a substrate 100 made of quartz glass or a silicon wafer.

The p-Si film 101 is formed by, for example, a-S by an LPCVD (low pressure CVD) method using disilane gas or a PECVD (plasma CVD) method using monosilane gas.
An i-film is deposited, and the entire surface of the a-Si film is irradiated with an excimer laser to perform laser annealing to crystallize the a-Si film.

Then, CV is formed on the p-Si film 101.
An interlayer insulating film 102 made of SiO ₂ is formed by a method D or the like (step (a) in FIG. 2).

Next, after a photoresist is applied on the interlayer insulating film 102 in which a contact hole is to be formed, a resist film 103 having an opening 103a as a contact hole pattern is formed in a contact hole forming portion by photolithography. (Step (b) of FIG. 2).

Next, using the resist film 103 as an etching mask, a contact hole C is formed in the interlayer insulating film 102 by reactive ion etching using, for example, a mixed gas of fluorinated gas CHF ₃ and SF ₆ as an etching gas. (Step (c) in FIG. 2).

At this time, in the step (b) of FIG. 2, the reaction gas (CHF ₃ , SF ₆ ) is ionized to generate a chemically extremely active radical F *, and this radical F *
Collides with and reacts with the SiO ₂ film as the interlayer insulating film 102 to form a contact hole C, and at the same time, collides with the resist film 103 as an etching mask and combines with carbon (C) as a constituent element of the photoresist. and, polytetrafluoroethylene-based material as a residue of the photoresist _(-CF 2 _CF 2 -) generating a n.

Then, the photoresist residue 104
Part of the contact hole enters the contact hole C during the etching and adheres to the inner wall of the contact hole C (see step (c) in FIG. 2).

Here, a residue removing step of removing the photoresist residue 104 attached to the inner wall of the contact hole C as described above is performed.

The residue removing step includes an O ₂ plasma treatment (step (d) in FIG. 2) and a cleaning treatment (step (e) in FIG. 2).
It consists of a combination.

[0036] That is, in the step of FIG. 2 (d), by irradiating O ₂ plasma with respect to the contact hole C, and then oxidizing the polytetrafluoroethylene-based material as a residue 104 of the photoresist by O ₂ plasma O ₂ plasma treatment for easy removal is performed. The O ₂ plasma is generated by, for example, irradiating an O ₂ gas with ultraviolet rays.

Next, in the step (e) of FIG. 2, a cleaning process is performed in which the entire substrate is immersed in a liquid release agent L.
The polytetrafluoroethylene-based material as the photoresist residue 104 is removed by softening or dissolving.

As the release agent L, for example, a mixed solution of 98% sulfuric acid and 2% hydrogen peroxide, or as an organic alkali release agent, for example, trade name S502A manufactured by Tokyo Ohka Kogyo Co., Ltd.
Can be used.

During the cleaning process, the contact hole C is irradiated with an ultrasonic wave of 1 MHz from an ultrasonic oscillation source, so that the polytetrafluoroethylene as a photoresist residue 104 is formed by the peeling effect of the ultrasonic vibration. Ethylene-based substances may be removed more effectively.

Further, if the photoresist residue 104 still remains after the O ₂ plasma treatment in the step (d) and the cleaning treatment in the step (e) of FIG. Steps (d) and (e) are repeated a plurality of times until the metal is removed. Then, in a state where the photoresist residue 104 containing a polytetrafluoroethylene-based substance attached to the inner wall of the contact hole C is completely removed by this residue removal step, an Al film or the like is formed as the conductive film 105 by sputtering or the like. Is formed (step (e) of FIG. 2).

At this time, since the inner wall of the contact hole C is in a clean state, the adhesion state of the Al film as the conductive film 105 is also good, and disconnection due to peeling of the conductive film 105 can be prevented beforehand. The reliability of a semiconductor device such as an active matrix substrate and an LSI can be improved. In this embodiment, the case where the etching for forming the contact hole C is reactive ion etching has been described. However, the present invention is not limited to this. The anisotropic dry etching method using a fluorine-based gas is generally used. May be used.

In this embodiment, the case where a mixed gas of CHF ₃ and SF ₆ is used as the etching gas has been described. However, the present invention is not limited to this, and the case where CHF ₃ gas and SF ₆ gas are used alone is used. The same applies to the case where a fluorine-based gas such as CF ₄ is used.

The method of manufacturing a semiconductor device according to the present invention can also be applied to a method of forming a through hole that penetrates and connects an insulating layer between wiring layers.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device manufactured by using the method of manufacturing a semiconductor device according to the present invention will be described below with reference to FIGS.

(First Embodiment) FIG. 3A is a sectional view showing a schematic structure of a TFT of a pixel electrode section 52 in the active matrix substrate AM shown in FIG. 1, and FIG. It is sectional drawing.

In FIG. 3A, the glass substrate 100
A conductive layer 101 is formed thereon by p-Si or the like, and a gate insulating film 120 is formed thereon by SiO2 or the like.

In a predetermined position of the gate insulating film 120, p-
A gate electrode 121 is formed of Si or the like, and a first interlayer insulating film 122 is formed thereon.

Then, according to the above-described embodiment, the contact holes C1, C2 reaching the drain region 101a and the source region 101b of the conductive layer 101 through the first interlayer insulating film 122 and the gate insulating film 120 by reactive ion etching or the like. C2 is formed (see FIG. 3B).

At this time, contact holes C1 and C2
As described in the embodiment, since the O ₂ plasma treatment and the cleaning treatment with the solvent are performed, the inner wall is kept in a clean state.

Then, in the contact holes C1 and C2, a conductive material such as p-Si is sputtered to form a drain electrode 123 and a source electrode 124.

A second interlayer insulating film 125 is formed on the drain electrode 123 and the source electrode 124, and the second interlayer insulating film 125 is formed by reactive ion etching or the like according to the above embodiment.
A contact hole C3 penetrating through the interlayer insulating film 125 and reaching the drain electrode 123 is formed (see FIG. 3B).

At this time, since the contact hole C3 is subjected to the O ₂ plasma treatment and the cleaning treatment with the solvent as described in the embodiment, the inner wall is kept in a clean state. Then, ITO is sputtered in the contact hole C3 to form the pixel electrode 52. By performing such a cleaning step, all the residue is removed, and disconnection and breakage of the ITO caused by the residue can be prevented, and the connection between the thin film transistor as the switching element and the pixel electrode (ITO) can be surely achieved. It can be carried out.

(Second Embodiment) FIG. 4A is a sectional view showing a schematic configuration of an antistatic wiring portion as a kind of a peripheral circuit in the active matrix substrate AM shown in FIG. 1, and FIG. It is an expanded sectional view of an important section.

In FIG. 4A, the glass substrate 100
The conductive layer 101 is formed of p-Si or the like, and the first interlayer insulating film 122 is formed thereon.

An insulating film 130 made of a fired polysilazane film is formed thereon, and an insulating film 131 is further formed thereon by a CVD method.

Then, according to the above-described embodiment, the cutting holes H1 and H2 reaching the conductive layer 101 through the insulating films 130 and 131 are formed by reactive ion etching or the like (see FIG. 4B). ).

At this time, since the cutting hole H1 is subjected to the O ₂ plasma treatment and the cleaning treatment with the solvent as described in the embodiment, the inner wall is kept in a clean state.

Then, a conductive material such as Al is sputtered on the bottom of the cutting hole H1 to form the short-circuit wiring 132.

(Third Embodiment) Here, FIG.
FIG. 2 is a cross-sectional view showing a schematic configuration of a terminal portion in the active matrix substrate AM shown in FIG. 1, and FIG.

In FIG. 5A, the glass substrate 100
A conductive layer 101 is formed thereon by p-Si or the like, and a conductive material such as Al is sputtered thereon to form a first pad wiring 1.
40 are formed.

A first interlayer insulating film 122 is formed on the first under-pad wiring 140.

Then, according to the above-described embodiment, contact holes C 4, C 5, and C 6 that penetrate the first interlayer insulating film 122 and reach the first under-pad wiring 140 are formed by reactive ion etching or the like.

At this time, contact holes C4, C5,
As described in the embodiment, since the C6 is subjected to the O ₂ plasma treatment and the cleaning treatment with the solvent, the inner wall is kept in a clean state.

Then, the contact holes C4, C5, C
In 6, a conductive material such as Al is sputtered to form a second pad lower electrode 141.

An insulating film 130 made of a fired polysilazane film is formed on the second pad lower electrode 141, and an insulating film 131 is further formed thereon by a CVD method.

Then, according to the above-described embodiment, contact holes C7 and C8 that reach the second pad lower electrode 141 through the insulating films 130 and 131 are formed by reactive ion etching or the like (FIG. 5 (b)). )reference).

At this time, contact holes C7, C8
As described in the embodiment, since the O ₂ plasma treatment and the cleaning treatment with the solvent are performed, the inner wall is kept clean, and the contact holes C7 and C8 have Al in the contact holes C7 and C8.
And conductive materials such as pads 142, 143,
144 are formed.

[0068]

As described above, according to the method of manufacturing a semiconductor device according to the present invention, the residue of the photoresist adhered to the inner wall of the contact hole is effectively removed by the plasma treatment and the cleaning treatment with the solvent. Can be
There is an effect that a conductive film can be favorably formed in a contact hole, and further, there is an effect that reliability of an active matrix substrate for a liquid crystal device and a semiconductor device such as an LSI can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a liquid crystal panel using an active matrix substrate using a TFT manufactured by applying the method of manufacturing a semiconductor device according to the present invention.

FIG. 2 is a process chart showing an example of a process of forming a contact hole in a method of manufacturing a semiconductor device according to the present invention.

FIG. 3 is a cross-sectional view showing a first embodiment of a semiconductor device manufactured by applying a contact hole forming process in a semiconductor device manufacturing method according to the present invention.

FIG. 4 is a sectional view showing a second embodiment of a semiconductor device manufactured by applying a contact hole forming process in the method of manufacturing a semiconductor device according to the present invention.

FIG. 5 is a cross-sectional view showing a third embodiment of a semiconductor device manufactured by applying a contact hole forming process in the method of manufacturing a semiconductor device according to the present invention.

FIG. 6 is a process diagram showing an example of a conventional contact hole forming process.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 substrate (glass substrate or silicon wafer) 101 p-Si film (conductive layer) 102 interlayer insulating film (SiO ₂ film) 103 photoresist (mask) 104 photoresist residue containing polytetrafluoroethylene-based substance 105 conductive film C Contact hole L Liquid release agent AM Active matrix substrate C1-C8 Contact hole H1 Cutting hole

Claims (8)

[Claims] 1. A method for manufacturing a semiconductor device comprising a switching element and an insulating film formed on a substrate, comprising: forming an opening in the insulating film; and cleaning the opening by plasma processing. And a step of cleaning the opening with a solvent. 2. The manufacturing method of a semiconductor device according to claim 1, wherein an etching mask is formed on the insulating film using a photoresist, and the opening is formed by dry-etching the insulating film using an etching gas. Method. 3. The method according to claim 2, wherein said etching gas is a fluorine-based gas. 4. The photoresist residue contains a polytetrafluoroethylene-based substance formed by combining carbon atoms contained in the photoresist with fluorine atoms contained in the etching gas. The method for manufacturing a semiconductor device according to claim 2 or 3, wherein 5. The method according to claim 2, wherein the dry etching is reactive ion etching using a fluorine-based gas. 6. The method according to claim 1, wherein the plasma processing and the cleaning processing are performed alternately a plurality of times.
A method for manufacturing a semiconductor device according to any one of claims 1 to 5. 7. The method for manufacturing a semiconductor device according to claim 1, wherein the solvent is a mixture of sulfuric acid and a hydrogen peroxide solution. 8. The method according to claim 1, wherein the solvent is an organic alkali-based release agent.