JPS6295874A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To realize good connection without deterioration of electrical connection between barrier metal and impurity region by executing heat processing of short period by irradiation of infrared beam and lowering surface concentration of impurity region. CONSTITUTION:After formation of contact hole 11 as the aperture, the AsSG film 10 as the reflow film is subjected to reflow by irradiation of infrared beam. The impurity regions 6, 7 are annealed by irradiation of infrared beam and irradiation of infrared beam is carried out within a short period. Thereby, heat processing is carried out without decreasing surface impurity concentration of regions 6, 7. Accordingly, good connection can be realized even if the barrier metal 12 is deposited on the regions 6, 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of applying infrared irradiation to a semiconductor device on which a barrier metal is formed.

[Summary of the invention]

This invention simplifies the manufacturing process and achieves good connections by short-term heat treatment using infrared irradiation in a method for manufacturing semiconductor devices in which a barrier metal is deposited and impurity regions are activated and reflowed. It is something to do.

[Conventional technology]

Generally, in semiconductor devices such as MOS (MOS) transistors, metal wiring is sometimes provided through a barrier metal in an impurity region formed by ion implantation or the like.

This barrier metal is deposited for the purpose of preventing interaction between Al wiring and silicon substrate, etc., such as the generation of spikes in metal wiring such as Al wiring. ), TiN (titanium nitride)
, A/-3> (a material containing, for example, 1% Si in Ai2) is deposited to make an electrical connection between the barrier metal and metal wiring.

By the way, to briefly explain a conventional method for manufacturing a semiconductor device, for example, first, a gate electrode of a MOS transistor is patterned, and then ions are implanted to form a source region and a drain region using, for example, BF2+ as a dopant. Then, annealing is performed to activate the source and drain regions, and PSG is used as an interlayer insulating film.
An insulating film containing impurities such as (phosphorus silicate glass) or As5G (arsenic silicate glass) is deposited. Subsequently, after the impurity-containing insulating film is deposited, a window is opened to make contact, and reflow is performed to planarize the impurity insulating film. Then, a barrier metal made of the above-mentioned Ti and TiN and a metal wiring made of the above-mentioned AJ-5i are applied to this window portion.

Here, to explain one reflow process, an electric furnace is used to maintain a predetermined temperature (for example, 1050°C in the case of PSG).
, 90° C. in the case of As5G) and the time (for example, about 10 minutes).

[Problems to be Solved by the Invention] As described above, in semiconductor devices, a barrier metal is sometimes deposited for the purpose of preventing mutual reaction between Al wiring and a silicon substrate.

However, when a barrier metal is deposited, connection resistance tends to increase, making it difficult to achieve a good connection. When the impurity region is annealed or reflowed through the steps described above, the connection between the barrier metal and the impurity region becomes more problematic due to a decrease in surface concentration.

That is, heat applied to annealing the impurity region or reflowing the impurity-containing insulating film reduces the impurity concentration on the surface of the impurity region due to the redistribution of impurities in the impurity region. For this reason, although it is necessary to maintain conductivity by using a barrier metal, problems arise in that good contact cannot be made due to process problems.

In addition, in the manufacturing process of semiconductor devices, there is a demand for simplification of the manufacturing process in order to reduce costs, etc., but conventional semiconductor device manufacturing methods require a large number of steps and the time required for processing. It costs a lot.

Therefore, in view of the above-mentioned problems, the present invention provides a method for manufacturing a semiconductor device that enables good connection between the barrier metal and impurity regions of a semiconductor device using a barrier metal, and simplifies the manufacturing process. purpose.

[Means for solving problems]

The present invention includes the steps of depositing an impurity-containing insulating film on a substrate on which an impurity region is formed, forming an opening in the impurity-containing insulating film, and irradiating infrared rays so as not to lower the surface concentration of the impurity region. a step of simultaneously reflowing the impurity-containing insulating film and activating the impurity region; and a step of forming a barrier metal in the opening and further providing metal wiring to connect the impurity region and the metal wiring. The above-mentioned problems are solved by a method of manufacturing a semiconductor device characterized by having the following.

[Effect]

The present applicant previously filed an invention disclosed in Japanese Patent Application No. 181540 of 1981 as a method for manufacturing a semiconductor device in which activation and reflow are performed simultaneously by infrared irradiation or the like.

The present application further focuses on the surface impurity concentration of semiconductor devices using barrier metal, maintains the impurity concentration in the impurity region under the barrier metal by infrared irradiation, realizes good connection, and enables activation and reflow. The aim is to simplify the manufacturing process by making it a single process.

In other words, infrared irradiation is performed in a short period of time to prevent the surface concentration from decreasing through heat treatment, preventing a decrease in the surface impurity concentration in the impurity region under the barrier metal, and connecting the metal wiring and the impurity region through the barrier metal. make a good connection.

In this case, activation of the impurity region and reflow of the impurity-containing insulating film are performed simultaneously. Therefore, an excellent semiconductor device can be easily manufactured not only by simplifying the process but also by maintaining low resistance on the surface of the impurity region.

〔Example〕

A preferred embodiment of the present invention will be described.

Examples of impurity-containing insulating films used in the method of manufacturing a semiconductor device of the present invention include PSG, As5G, BPSG, and BSG.
, 5bSG, or the like can be used. In addition, heat sources for the short-time heat treatment of the present invention include lamp light (continuous incoherent light with a wavelength of 0°4 to 4.0 μm), infrared rays by black body radiation from a carbon heater, and long wavelength irradiation over a large area. A laser beam or the like may also be used.

The method for manufacturing the semiconductor device of this embodiment will be explained based on an example of a MO3I transistor as shown in FIG.

First, in the manufacturing method of the semiconductor device of this embodiment, a field insulating film 2 is formed on a semiconductor substrate 1, such as a P-type silicon substrate, by using a selective oxidation method, and then a field insulating film 2 is formed to a thickness of about 100 mm, for example. A predetermined gate electrode 4 is patterned through the gate insulating film 3 .

An impurity region 6.7 is formed using the patterned gate electrode 4 and the self-alignment line by ion implantation or the like.

In the case of ion implantation, the impurities introduced can be, for example, B'' and BF2+. These impurity regions 6 and 7 are used as the source region and drain region of a MOS transistor, respectively. As shown, a spacer 5 may be used to form an LDD structure.

After forming the impurity region 6.7, an oxide film 8 as an interlayer insulating film, a nitride film 9, and an As5G film 1 as an impurity-containing insulating film.
0 is deposited and formed. For example, the oxide film 8 is formed to a thickness of 500 nm by CVD, the nitride film 9 is similarly formed to a thickness of 500 nm, and the As5G film 10 is formed to a thickness of 5000 nm. Conventionally, after forming the impurity regions 6.7, these impurity regions 6.7 were annealed.

However, in this embodiment, annealing is also performed at the same time in one reflow process, which will be described later.

After forming an insulating film such as As5G film 10 as an interlayer insulating film, a contact hole 11.11 is formed to connect to the impurity region 6.7. Formation of the contact hole 11.11, which is the opening, is performed using photolithography technology, and the oxide film 8, the nitride film 9, and the As5G film 10, which is the impurity-containing insulating film, are formed in the contact hole 11.11.
1.11 is removed.

Subsequently, after forming contact holes 11.11, which are openings, the As5G film 10, which is a reflow film, is reflowed by infrared irradiation. By this infrared irradiation, the impurity region 6.7 is simultaneously annealed, and furthermore, since this infrared irradiation is performed in a short time, the impurity region 6.7 is annealed at the same time.
．． The heat treatment is performed without reducing the surface impurity concentration of No. 7.

Therefore, even if a barrier metal 12 as described later is applied, a good connection can be achieved.

In addition, in the conventional manufacturing method of semiconductor devices, reflow was performed using an electric furnace, but in the present invention, the heat treatment is performed in a short time, for example, about 10 seconds, and the time is also significantly shortened. This, together with the ability to perform annealing and reflow at the same time, is an advantage in terms of the process.

After reflowing the As5G film 10 and annealing the impurity region 6.7, the barrier metal 12 and the metal wiring vA1 are
Apply 3. The barrier metal 12 is made of, for example, Ti and I approximately 500 mm thick.

It is made of, for example, TiN with a thickness of 0.00 mm. The metal wiring 13 is made of Al-8i, for example, and is deposited to a thickness of 4000 mm. Selective etching is performed leaving a pattern connecting the barrier metal 12 and the metal wiring wA13 to the contact hole 11.11 to complete the wiring.

As described above, the semiconductor device manufacturing method of this embodiment simultaneously performs reflow and annealing using infrared irradiation, and utilizes the short-time heat treatment function of this infrared irradiation to reduce the surface impurity concentration in impurity reflow 6.7. The above reflow and annealing are performed without changing the distribution. Therefore, good electrical connection can be maintained without reducing the impurity concentration on the surface of the impurity region 6.7, which is the portion connected to the barrier metal 12 of the semiconductor device having the barrier metal 12. Furthermore, since the surface impurity concentration can be maintained high, the ion dose during ion implantation can be reduced, and the time for the ion implantation process can be shortened.

Note that in the embodiments described above, the conductivity type is not limited. Further, although the As5G film is used as the impurity-containing insulating film, it is not limited to this, and for example, PSG may be used.

An impurity-containing insulating film such as BPSG, BSG, 5bSG, etc. can be used. In addition, the heat source for short-time heat treatment is not limited to lamp light (continuous incoherent light with a wavelength of 0.4 to 4°0 μm), but includes, for example, infrared rays from the black body radiation of a carbon heater, and long-wavelength, large-area light. A laser beam or the like that irradiates the light may also be used.

〔Effect of the invention〕

The method for manufacturing a semiconductor device of the present invention performs heat treatment using infrared irradiation in a short time without reducing the surface concentration of the impurity region. Therefore, a good connection can be achieved without deteriorating the electrical connection between the barrier metal and the impurity region. realizable. Since activation and reflow are performed simultaneously, the manufacturing process can be simplified in terms of the number of steps and time.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor device manufactured by the method for manufacturing a semiconductor device according to the present invention. ■... Semiconductor substrate 6... Impurity region 7... Impurity region 10... As5G film (impurity-containing insulating film) 11...
Contact hole 12...Barrier metal 13...Metal wiring patent applicant: Sony Corporation representative Patent attorney: Koike Mimi: Sakae Tamura

Claims (1)

[Claims] A step of depositing an impurity-containing insulating film on a substrate on which an impurity region is formed and forming an opening in the impurity-containing insulating film, and infrared rays for not reducing the surface concentration of the impurity region. A step of simultaneously reflowing the impurity-containing insulating film and activating the impurity region by irradiation, forming a barrier metal in the opening, and further providing metal wiring to connect the impurity region and the metal wiring. A method for manufacturing a semiconductor device, comprising the steps of: