JPS6180823A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the manufacturing method for the semiconductor device to be processes at a low temperature having few damage caused by the projection of light by a method wherein the light directly made to irradiate at least on a sample, in the process to be performed after a prescribed light projecting process is conducted, is brought in the specific wavelength or above. CONSTITUTION:When an etching is going to be performed on a protective film BPSG18, a wafer is arranged in reactive gas, the purpose of etching is easily accomplished by projecting a condensed light at the part to be etched. However, the wavelength of the light to be projected at least on the wafer directly is set at 200nm or above, and an etching is accomplished without forming the center of electron capture on a gate oxide film 11. On the other hand, when Al is going to be deposited, a light (ArF laser beam) with which trimethylaluminum will be decomposed is made to irradiate in parallel with the wafer, and a laser having the wavelength of 200nm or more such a XeCl laser beam (308nm) is convergingly made to irradiate on the wafer, and Al is deposited.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for producing hangihonsodo using photochemical reactions.
Regarding this.

[Technical background of the invention and its problems]

In recent years, integrated circuits have been increasingly miniaturized, and recently, prototypes of ultra-LSIs with a minimum pattern size of 1 to 2 [μm] have been developed. For example, in the etching process, reactive ion etching (React
ive Ion Etching; RIE)
Is it mainstream technology? In the process of the four-film stack I4, ion blating methods, plasma CVD methods, and the like, which are compatible with low-temperature processes, are widely used. However, all of these technologies are processes that use plasma, and the phenomenon of destruction of the gate oxide film (happy day) occurs.

Watanabe: Proceedings of the 5th Dry Process Symposium.

At present, there is a growing concern about radiation damage to the elements described in 4.4 Ki Gakkai, Tokyo, 1983).

As a non-irradiation damage process that does not use charged particles in contrast to the above-described plasma process, research is being actively conducted on thin film deposition, etching, non-irradiation diffusion, etc. using reversal photochemical reactions. This photoexcitation process enables maskless or selective deposition, etching, impurity doping, oxidation, and other processes that are difficult with other current processes.

In addition, since it is actually a low-temperature process, it is thought to be fully compatible with future processes for submicron devices.

Even in this original process, with the progress of thinning, when selectively irradiating light to perform etching, deposition, doping, etc., it is considered to use light with an extremely short wavelength to obtain high resolution. It will be done. The original process has an irradiation loss of 11y.
The reason for not exceeding J is that in addition to not using charged particles, the energy of light is very low, at several eV or less. Therefore, if high-energy rays such as deep ultraviolet, vacuum ultraviolet, or X-rays are used in the future, there is a risk of irradiation damage occurring.

[Purpose of the invention]

The present invention has been made in view of the above points, and its object is to provide a method for manufacturing a semi-specialized wood device using light, which causes less damage due to irradiation and which is a low temperature process.

[Overview of invention UJ]

The gist of the present invention is to use light irradiation to irradiate the surface of a semiconductor device when high temperature annealing of 800°C or higher is not possible with one maple of wheat that has been subjected to etching, deposition, etc. The purpose of the light is to use light with a wavelength of 2QQnm or more to prevent radiation damage that cannot be recovered by low-temperature annealing.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the irradiation loss μ in the silicon oxide film that is thought to be caused by high-energy photons or high-energy rays that cannot be recovered by low-temperature annealing, and to reduce the non-irradiation loss μ in the semiconductor process.

It is expected to be effective for low-temperature processing.

[Embodiments of the invention]

First, the experimental results ζ that formed the basis of the present invention will be explained. In recent years, the high integration of MO8 devices has progressed from miniaturization (n-).On the other hand, there is a desire to be self-sufficient in the power supply voltage used.As a result, the mechanical stress applied to devices has become severe and new One of them is the hot electron effect. As a means of reducing the particle size, we use the '-beam, X, hj (
There are phosphorography and dry processes, and the high-energy particles contained in these processes damage the oxide film and harden it as hot electrons are injected. M OS F E
During the production of T, the hot electrons generated in the depletion 1 convex near the drain flow through the gate oxide film at 14 from the high i field with energy that can overcome the interface barrier of 1 (1j, for example, 5i-8iQ2). It is known that a part of the hot electrons flowing through the gate f carbide film is captured by the capture center and changes the threshold value.

Therefore, '・Engine' associated with etching, ':F-Jrii
The occurrence of the 3R center was investigated. FIG. 1 is a structural perspective view of an etched sample. Field region (1) is formed by LOCO8 method and gate oxidation 11Q (2
) on N+poly-8i (3) is etched in each direction using resist (4) as a mask. Also, the sample is
As shown in Figure (a), even after etching, the area (2) of the film is completely poly-8i. The etching method was the usual parallel + plate temperature reactive ion etching 11fi (RIE), (1,'P
A method of perpendicular irradiation with XeC1x ximer laser light (308 nm, 4 eV), and etching with fluorine radicals: This is a chemical dry etching method (CDE) that is thought to not cause any radiation damage; 74. Arg'xxiffL/-the light (19
3nm, 6.3eV)
h'l foot G went.

Thereafter, the bath samples were subjected to RIE, XeC1, CDE, Ar
Call it F.

Measurement method 6: A pulse voltage of several tens of volts was applied between the substrate f51 and poly y-8i (31) of the sample substrate after etching as shown in Figure 1 (cl), and avalanche was applied to inject six particles from the substrate 1ill. Injection method), measure the change in pressure on the flat band of this gapacitor with respect to the injection amount. The electron capture center in the film is shown.

Figure 2 shows the shift dip in the flat band voltage VFB due to avalanche injection measured by the above-mentioned device for the injected load. The difference between each etching method is small and within the error range.

On the other hand, 3r:A is the measurement result of the sample after etching shown in FIG. 1(t)l, in which a thin oxide film region similarly etched is exposed at 1j' after etching. Looking at this, XeC1
It is thought that the occurrence of electron capture centers is similar to that of CDE, but there is a clear difference between f(, IE and 8rF; the existence of d(1,1! Han center) is confirmed. Capacitance-voltage characteristics (C-
When measuring the V characteristics, there are no significant differences between the etching methods and samples. From this, as shown in Figure 3,
E, quadruplets generated in ArF; I4 stable center is 4-ki ζ
It can be seen that this is a ``tral trap'' with the central ``α electron capture center''. Further, this neutral trap is not reduced by heat treatment at 450° C. for 30 minutes in forming gas, and high temperature heat treatment of about 800° C. is required to restore it. The cause of the occurrence of mainly electronic capture in this disaster was 41
From the comparison of the samples shown in Figures (al and fbl), it is thought that the infiltration occurred through the area of the thin oxide film exposed during R, IE overetching or ArF laser irradiation, and high-energy photons in the plasma or ArF laser penetrated into the thin gate oxide. It is thought that the particles were formed by repeated reflections within the film.

Therefore, a similar experiment was conducted by irradiating the light from a Hl lamp through a filter that does not transmit light with a wavelength of 200 nm or less. As a result, the development of the single-child capture center was CD without radiation damage.
It was revealed that the etching efficiency was comparable to that of E, XeCj laser light etching.

The present invention was made based on the above experimental results. Below 1
Examples are shown and explained below. Figure 4 shows MOS FET
It is a process chart of production. By selective oxidation using Sl, N, film q) as a mask, the element region (9) is separated by a field oxide film (10) (41'lJ (a) fbl
). Here, 8 is an inverted, direct mounting formed by a field τ field inflated silane. Gate oxide film (11)
Then, poly-8i (12) was deposited, the resistance was lowered by phosphorus diffusion, and an etching mask ([3) was formed with resist (Fig. 4(C)).

Next, the poly-di is etched and the gate electrode (14) is formed.
(Drainage 41Aid)). Up to this step, it is not necessary to use light with a wavelength of 2,500 m or more as specified in the present invention, and each of the 11 treatments can be performed using high-energy light. However, the ringing requires 11 high-temperature annealing rounds around the irradiated Kuniho. An impurity is added slightly to form a junction region for the drain and source portions (15). With the future miniaturization of vLSIs, this junction will need to be formed extremely shallowly, and it will not be possible to perform advanced heat treatment to change the impurity distribution in subsequent steps.

Therefore, from now on, it is necessary to use light with a wavelength of 250 nm or more as shown in this explanation. In the actual process, this n A
Recording (16) is carried out, and B P is added as a protective film.
S G (1,7) etc. are multiplied by J′l+. Further, depending on the device, steps fd) to Ig) are repeated to form two gates and conduct multiple wirings. Therefore, the processes to which this invention is applied account for more than half of all VLSI processes.

Next, some individual processes will be explained.

First, the floor praise B P S G (1
8) Line up the platforms for etching. This etching is accomplished by placing the wafer in a reactive gas and focusing light onto the area to be etched. However, according to the present invention, at least the light directly irradiated onto the wafer has a wavelength of 200 nm or more,
1L can be etched without creating a 1L Koura catch center) 1 Noah. In addition, the wavelength is 200n to activate the reactive gas.
If light with a wavelength of less than m is required, light of a predetermined wavelength may be passed above the sample parallel to the sample.

On the other hand, taking deposition as an example, the 1L1 wiring shown in Figure 4) is achieved by irradiating ArF laser light in an Al(CH,), (T11 methylaluminum) atmosphere.However, As mentioned above, when the A-rF laser light (wavelength: 193 nm) enters the gate 9 and the dioxide film, it makes the tetrad trapping center immune. Therefore, this book%ry4j is the source of disassembling Trimesen Rusalumi (ArF laser source)
For example, XeCl laser light of 200 nm or more is used to selectively irradiate the wafer and the half-row of the wafer.
Deposition may be performed by irradiating the wafer with a wavelength of 308 nm).

In this way, as an alternative to the plasma process, which is widely used for null pattern formation, an optical process is attracting attention because it can perform oxidation and wavenumber deposition in one place at a low temperature (7J) with less damage, and has excellent IXR efficiency. . In addition, anisotropic and quasi-etching by light irradiation is also being carried out, and in the future
Full-scale application to LSI technology is expected.At present, a great invention is exerting tremendous power to use the optical process, which has many possibilities, as a damage-free process.

In addition, the 夷 i in FIGS. 21 and 3, which were the key to the present invention,
Even if you use 2 sources of light energy, FB is better than fruits and vegetables.
It can be seen that irradiation damage can be prevented by preventing the optical power S from penetrating to the active head (gate oxide film) of the transistor. Therefore, even in the AJM layer (see Figure 4), after growing AI to an appropriate thickness, ArF light may be directly irradiated. As described above, the present invention exhibits great effects by not irradiating the completed gate film with a high-energy source.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the auxiliary material used in the explosion, which is the most important feature of the present invention. The figure shows the process Vr [! [Figure i. 11... Gate oxide film, 14... poly-8i,
15... Impurity doped region, 16... Aj wiring pattern, 18... Protective oxide film. Representative Patent Attorney Kensuke Chika (and 1 other person) Beak No. 1 Figure 1? Figure 4Figure 4

Claims (5)

[Claims] (1) In a method for manufacturing a semiconductor device in which a sample placed in a processing gas is irradiated with light for processing, at least the light that is directly irradiated onto the sample in a step after a predetermined light irradiation treatment has a wavelength of 200 nm or more. A method for manufacturing a semiconductor device, characterized in that: (2) The treatment performed by the light irradiation includes etching,
2. The method of manufacturing a semiconductor device according to claim 1, comprising: deposition, addition/diffusion of impurities, and oxidation. (3) The method for manufacturing a semiconductor device according to claim 1 or 2, wherein the light is selectively irradiated onto a sample. (4) The method for manufacturing a semiconductor device according to claim 1, wherein the gas is activated by the light irradiation. (5) The method for manufacturing a semiconductor device according to claim 1, wherein the sample is at least a semiconductor substrate or an oxide film is formed on the semiconductor substrate.