JPH02103937A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To remove dicer damage at the time of wafer cutting so as to improve yield rate in manufacturing by providing an insulating film and an etching end detection film on a semiconductor substrate and forming a contact hole, and forming a conductive film only in the contact hole. CONSTITUTION:A gate oxide film 12, a gate electrode 14, a protective film 15, and source and drain regions 13 are formed on a silicon substrate 1, and a scribe region is formed being separated from the element region by a field oxide film 11. An SiO2 film 2 on the whole face and a polysilicon film 3 as an etching end detection film are formed, and the end detection film 3 is etched and the end detection film 3 is left at one part of the scribe region. Next, a PSG film 4 is formed and a photoresist film 5 is formed, and the first opening 6 and the second openings 7 and 8 are formed, and then the end detection film 3 is exposed, and contact holes 71 and 81 are formed. After removing the end detection film 3 from the first opening 6, tungsten films 9 and 10 are selectively grown in the contact holes 71 and 81. This way, dicer damage at cutting can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a wiring layer in a contact hole.

The purpose is to form a flat conductive film only within the contact hole.

forming a first insulating film and an etch end point detection film on the surface of the semiconductor substrate in this order; etching the etch end point detection film by partially masking the scribe region of the semiconductor substrate; and etching the etch end point detection film in a part of the scribe region; a step of leaving a detection film; a step of forming a second insulating film on the entire surface and forming a mask having a first hole above the etch end point detection film and a second hole above the element region; the first opening and the second opening
The second insulating film is removed by dry etching from the opened ticket to expose the etch end point detection film, and the second insulating film and the first insulating film are removed to form a contact hole exposing the semiconductor substrate. With the process.

A semiconductor device comprising: removing the etch end point detection film from the first opening by wet etching; and filling the contact hole by selectively growing a conductive film on the semiconductor substrate in the contact hole. It is configured according to the manufacturing method.

[Industrial application field]

The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a wiring layer in a contact hole.

As semiconductor integrated circuits become smaller and contact holes become smaller, coverage of wiring layers within the contact holes becomes a problem. FIG. 2 is a diagram explaining the coverage inside the contact hole, where l is the semiconductor substrate, 41
42 represents an insulating film, and 42 represents a wiring layer.

As the miniaturization of semiconductor integrated circuits progresses, the width of contact holes tends to become smaller and smaller, and the ratio of depth to width tends to become larger and larger. Therefore, when aluminum (^l), for example, is vapor-deposited as an electrode, the inside of the contact hole becomes shaped as shown in FIG. 2, causing a problem that the coverage range is not uniform.

Therefore, it is necessary to develop a method of filling the inside of the five contact holes to form a wiring layer with good coverage.

[Conventional technology]

Conventionally, in order to solve the above-mentioned coverage problem, tungsten (W), for example, is selectively formed in the contact hole by a vapor phase growth method to fill the contact hole flatly.

FIG. 3 is a diagram explaining a conventional example of an MO3I-transistor, in which 1 is a semiconductor substrate, 11 is a field oxide film, 1
2 is a data 1-oxide film, 13 is a source/drain region, 1
4 is a gate electrode, and 15 is a protective film.

41 is an insulating film, 5 is a photoresist mask, 6 is an opening,
71 and 81 are contact holes, 9.10 is a conductive film,
20 represents a scribe area conductive film.

FIG. 3(a) shows a state in which contact holes 71 and 81 for electrode wiring are formed in the element region, and openings 6 are also formed in the scribe region. When the contact holes 71 and 81 are formed by dry etching the insulating film 41 using the photoresist mask 5 as a mask, the etch end point is detected by simultaneously etching the scribe region to form the opening 6. That is, if only the inside of the contact hole is etched, the area to be etched is small, making it extremely difficult to detect the etch end point2.Therefore, when etching is performed by forming a wide bloom in a scribe area that is not related to the device characteristics, the semiconductor substrate (1), for example, a Si substrate, is etched. When the contact hole is exposed, the end point of the 7th hole is detected and the contact hole formation is completed.

Thereafter, as shown in FIG. 3(b), for example, tungsten (W) is selectively grown in the contact hole by vapor phase growth to form a conductive film 9. Although IO is formed, a tungsten (W) film 20 also grows on the silicon substrate in the scribe region.

The tungsten film 20 formed in the scribe area may damage the blade of a dicer when cutting the wafer into chips in a secondary process, resulting in two problems. Furthermore, since the area of the tungsten film 20 formed there is large, there is also the problem that the tungsten film peels off and becomes dust.

[Problem to be solved by the invention]

Therefore, although the conventional method solves the problem of coverage of the conductive film within the contact hole, a new problem arises when cutting the wafer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for solving the above-mentioned problems by forming contact holes with good controllability and embedding a conductive film flatly only in the contact holes.

[Means to solve the problem]

A step of forming a first insulating film 2 and an etch end point detection film 3 in this order on the surface of the semiconductor substrate 1 when forming contact holes and wiring in the semiconductor substrate 1 on which the elements are formed;
A step of partially masking the scribe region of the semiconductor substrate l and etching the etch end point detection film 3 to leave the etch end point detection film 3 in a part of the scribe region;
forming an insulating film 4 and forming thereon a mask 5 having a first opening 6 above the etch end point detection film 3 and second openings 7 and 8 above the element region; 6 and the second
The second insulating film 4 is formed by tri-etching from 7.8 onwards.
forming a contact hole 71.81 exposing the etch end point detection film 3 by removing the second insulating film 4 and the first insulating film 2 to expose the semiconductor substrate 1;
A step of removing the etch end point detection film 3 from the first hole 6 by wet etching, and removing the contact hole 71.
．． The above problem is solved by a method of manufacturing a semiconductor device including a step of selectively growing a conductive film 9.10 on the semiconductor substrate 1 at 81 to fill the contact hole 71.81.

[Effect]

According to the present invention, when forming the contact holes 71, 81 by dry etching, the end point can be clearly known and the contact holes can be formed with good controllability. If the first insulating film 2 is formed to have a smaller thickness difference than the second insulating film 4, the contact hole 71. In this case, most of the first insulating film 2 is removed and the semiconductor substrate 1 is exposed. It should be noted that dry etching can be further completed a little after it is determined that the semiconductor substrate 1 in the scribe area is exposed.

When selectively growing a conductive layer such as tungsten, the first insulating film 2 remains in the scribe region and the surface of the semiconductor substrate 1 is not exposed, so it is selectively grown only in the contact holes 71 and 81 of the element region. be able to grow.

〔Example〕

FIGS. 1(a) to 1(f) show examples of the present invention.

It is a figure explaining the process of formation of the contact hole in MO3I-transistor. The following description will be made with reference to these figures.

Referring to FIG. 1(a), a gate oxide film 12 is formed in the element region of a silicon substrate 1 as a semiconductor substrate. Gate electrode 14. A protective film 15° source/drain region 13 is formed. field oxide film 11
There is a scribe area separated from the element area, where scribe lines are formed when cutting the wafer into chips.

SiO□ film 2 with a thickness of 200 mm as a first insulating film on the entire surface,
A polysilicon film 3 having a thickness of 2,000 wafers is formed in this order as an etch end point detection film.

Referring to FIG. 1(b), the scribe area is masked and the polysilicon film 3 is removed by etching, leaving the polysilicon film 3 in a part of the scribe area.

Refer to FIG. 1(C) After forming a PSGS composite film with a thickness of 1 μm as a second insulating film on the entire surface, a photoresist is applied, and then a first opening 6 with a width of 100 μm is formed on the top of the polysilicon film 3, and a source A photoresist mask 5 having second openings 7 and 8 with a diameter of 1.5 μm is formed above the drain region 13 .

See FIG. 1(d) First opening 6. The PSGS composite film is removed by dry etching simultaneously through the second openings 7 and 8, and the polysilicon film 3 is exposed. The appearance of the polysilicon film 3 can be determined from spectroscopic analysis of the reaction gas.

By the way, since the SiOz film 2 as the first insulating film is much thinner than the PSGS composite film as the second insulating film, at the time when the polysilicon film 3 is exposed, the second openings 7 and 8 are
Most of the underlying Si02 film 2 has also been removed. The etching is further advanced a little to completely remove the SiO□ film 2, exposing the silicon substrate 1 and forming contact holes 71 and 81.

Referring to FIG. 1(e), after masking the contact hole 71.81 and removing the polysilicon film 3 from the first opening 6 by wet etching to form the recess 61, the contact hole 71.81 is removed.
Masking 81 and photoresist mask 5 are removed.

SiO and film 2 remain at the bottom of the recess 61.

The silicon substrate l is not exposed.

Referring to FIG. 1(f), tungsten (W) is selectively grown on the silicon substrate l in the contact hole 71.81 by the vapor phase growth method, and the contact hole 71.81 is covered with a tungsten film 9.1 as a conductive film.
Fill with 0 and flatten.

In this way, the distribution layer A could be formed only within the contact hole.

Note that the conductive films 9 and 10 are not limited to tungsten, but other metals or compounds of metal and silicon can also be used.

Further, the etch end point detection film 3 is not limited to a polysilicon film, and a material having a lower etch rate than the second insulating film 4 can be used.

[Effects of the Invention] As described above, according to the present invention, contact holes can be formed with good controllability, a conductive film can be formed only in the contact holes, and a flat wiring layer can be obtained. the result,
When cutting the wafer into chips, there is no problem of damaging the cutters, which greatly contributes to improving manufacturing yields.

[Brief explanation of drawings]

Figure 1 shows an example. Figure 2 is a contact Figure 3 is a conventional example It is. In fig. ■ is a semiconductor substrate and is a silicon substrate. Coverage within the hole Con board. 2 is a first insulating film, which is a SiO□ film. 3 is an etch end point detection film, which is a polysilicon film. 4 is a second insulating film, which is a PSG film. 41 is an insulating film. 42 is a wiring layer. 5 is a photoresist mask. 6 is an opening, which is a first opening. 7.8 is the second opening. 61 is a dent. 71.81 is a contact hole. 9.10 is a conductive film, which is a tungsten film. 11 is a field oxide film. 12 is a gate oxide film. 13 is a source/drain region. 14 is a gate electrode. 15 is a protective film 20 is a scribe region conductive film, which is a tungsten film. (υsu (Lev r application Part 1 q C’ftAf) <d) 5 on the 11' side ￥y　1　Figure (fri2) Contactless 1st and 4th π valley 7th YJ 2 diagram (phantom (death) &L Kaidari 'g3 figure

Claims (1)

[Claims] When forming contact holes and wiring in a semiconductor substrate (1) on which elements are formed, a first insulating film (2) and an etch end point detection film (3) are provided on the surface of the semiconductor substrate (1). a step of forming in this order; and a step of etching the etch end point detection film (3) by partially masking the scribe region of the semiconductor substrate (1) and leaving the etch end point detection film (3) in a part of the scribe region. A second insulating film (4) is formed on the entire surface, and a first hole (6) is formed above the etch end point detection film (3) and a second hole (7, 8) is formed above the element area. Detecting the etch end point by removing the second insulating film (4) from the first opening (6) and the second opening (7, 8) by dry etching. forming contact holes (71, 81) exposing the semiconductor substrate (1) by exposing the film (3) and removing the second insulating film (4) and the first insulating film (2); , removing the etch end point detection film (3) from the first opening (6) by wet etching, and forming a conductive film (
9, 10) are selectively grown to form the contact hole (7).
1, 81) A method for manufacturing a semiconductor device.