JPH0777220B2 - Ag wiring forming method and Ag wiring forming apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Ag wiring forming method and an Ag wiring forming apparatus which are one of semiconductor element manufacturing processes.

[0002]

2. Description of the Related Art Conventionally, Al or Al alloy has been used as a wiring material for LSI.
Alternatively, in the case of Al alloy, there is a problem that the signal transmission speed is delayed due to the high resistance value and the reliability is lowered due to the low migration resistance. On the other hand, Au, Ag, and Cu have low resistance,
Since it has high migration resistance, it is expected as a wiring material replacing Al. Conventional Al and Al alloy wiring have been processed at a low temperature by forming AlCl ₃ having a high vapor pressure by a dry etching method using chlorine. However, since the Ag compound has a low vapor pressure, it is difficult to process it at a low temperature by the dry etching method. Further, the conventional wiring forming method is to deposit a wiring material on the entire surface, apply a resist, and perform light irradiation according to the wiring pattern,
By baking and developing, the resist is peeled off only at the desired processing portion, dry etching is performed, and then ashing,
A complicated process of removing the remaining resist by organic boiling or the like is performed. Further, the wiring forming technique tends to be multi-layered in order to improve reliability in Al wiring and to prevent diffusion in Au, Ag, and Cu wiring, and the process tends to be complicated.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In Ag wiring,
The vapor pressure of the Ag compound is low, which makes it difficult to perform low-temperature processing by dry etching. At present, in the semiconductor industry, an increase in man-hours due to multilayer wiring is a serious problem. The object of the present invention is to overcome the above problems,
It is an object of the present invention to provide a method for forming Ag wiring with a small number of steps and a device therefor for Ag which is difficult to process.

[0004]

According to the present invention, a step of depositing a halogenated Ag on a substrate, and applying a bias so that the substrate side becomes negative, a monochromatic light is applied to the halogenated Ag with a predetermined wiring pattern. An Ag wiring forming method comprising: a step of irradiating and irradiating the irradiated portion with Ag; a step of selectively removing the halogenated Ag by etching; and a step of heat-treating the substrate. Further, an apparatus for carrying out the method is capable of transporting a sample from a sputtering chamber in which a halogenated Ag is deposited, a vacuum from the sputtering chamber without being exposed to light, and a halogenated Ag An exposure chamber in which the exposure portion is exposed to Ag with a predetermined pattern is provided, and a sample stage to which a bias can be applied, a mask having a predetermined pattern, and a monochromatic light source are sequentially arranged in the exposure chamber. It is characterized by

[0005]

In the present invention, the halogenated Ag formed on the substrate is irradiated with light in accordance with the wiring pattern while a negative bias is applied to the substrate side. As a result, the light-irradiated site breaks the bond between halogen and Ag, and becomes a negatively charged halogen ion and a positively charged Ag ion. Due to the electric field applied to the substrate, halogen ions are electric field diffused to the surface side of the film, and Ag ions are electric field diffused to the substrate side. Since the recombination time of halogen ions and Ag ions is short, it is necessary to continue irradiation with light until there is no halogen at the irradiation site. As a result, the light-irradiated portion is only Ag, and the light-irradiated portion remains as halogenated Ag. Since the halogenated Ag and the Ag have greatly different etching rates, only the halogenated Ag can be selectively etched. Then, by performing heat treatment for recovering the crystallinity of Ag after the diffusion of halogen, a good quality Ag wiring can be formed without steps such as resist coating, development, and resist stripping.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is a configuration diagram of an embodiment of the Ag wiring forming apparatus of the present invention. As shown in FIG. 2, in this apparatus, a sputtering chamber 1 and an exposure chamber 2 are connected via a gate valve 3,
Sample 1 without breaking vacuum and without being exposed to light
3 can be transported from the sputtering chamber 1 to the exposure chamber 2. A bias can be applied to the sample table 4 of the exposure chamber 2. Further, the mask 5 and the monochromatic light source i
A line light source 6 is arranged so that exposure can be performed while applying a bias. As the monochromatic light source, a g-ray source or an x-ray source may be used instead of the i-ray source.

FIG. 1 is a sectional view of a sample showing an embodiment of the Ag wiring forming method of the present invention using the above apparatus. First, Ar (0.1 to 10 mTorr) + Cl ₂ (0.1 to 1)
1 m by the reactive sputtering method in an atmosphere of 0 mTorr).
As shown in (a), AgCl 8 is deposited on the Si substrate 7 to a film thickness of 0.1 to 1 μm. Next, it is conveyed from the sputtering chamber 1 to the exposure chamber 2 without exposing it to light. In the exposure room 2, FIG.
As shown in (b), a negative bias of 1 to 100 is applied to the substrate side.
With 0 V applied, the i-line light source 6 and the mask 5 of the mercury lamp were used, and the i-line 9 was formed on the AgCl 8 according to the wiring pattern.
Irradiate. As a result, the bond between Ag and halogen is broken at the site irradiated with light, and the negatively charged halogen ion 10
Then, positively charged Ag ions 11 are generated. The electric field applied to the substrate causes the Ag ions 11 to diffuse toward the substrate and the halogen ions 10 to diffuse toward the mask. By continuously irradiating light until the halogen is exhausted, FIG.
As shown in, the light irradiation site is only Ag12. Then A
The sample is taken out from the g-wiring forming device and only AgCl8 is etched with ammonia water.
A wiring pattern of Ag12 is formed on the substrate 7 as shown in FIG. Finally, anneal at 100-700 ℃,
The crystallinity of Ag is recovered.

In the above embodiments, the substrate is not a Si substrate, but GaAs, SiGe, SiO ₂ , Si _x N _1-x , T.
It can be applied to all materials used for semiconductor materials such as iN, TiW, W, and Co. Halogenated Ag is Ag
Similar results can be obtained with AgBr instead of Cl. Similar results can be obtained even if the sputtering gas used to form the halogenated Ag is Xe instead of Ar. Similar results can be obtained when the reaction gas is not Cl ₂ but contains at least one halogen in the halogenated Ag. The same result can be obtained with x-rays and g-rays instead of i-rays for monochromatic light. Similar results are obtained with a solution containing either concentrated hydrochloric acid or a potassium cyanide solution or a sodium thiosulfate solution instead of an aqueous ammonia as the halogenated Ag etchant.

[0009]

As described above, according to the present invention, it is possible to form a wiring made of Ag which is difficult to process. Further, since the wiring can be formed without the steps of resist coating, development, peeling, etc., the wiring can be formed by a small number of wiring forming steps, and the use of organic substances can be reduced.

[Brief description of drawings]

FIG. 1 is a process sectional view of a sample for explaining a method of the present invention.

FIG. 2 is a configuration diagram of an example of an apparatus of the present invention.

[Explanation of symbols]

 1 Sputtering chamber 2 Exposure chamber 3 Gate valve 4 Sample stage 5 Mask 6 i-line light source 7 Si substrate 8 AgCl 9 i-line 10 Halogen ion 11 Ag ion 12 Ag 13 Sample

Claims (2)

[Claims] 1. A step of depositing halogenated Ag on a substrate, irradiating the halogenated Ag with monochromatic light in a predetermined wiring pattern while applying a bias so that the substrate side becomes negative, and irradiating the illuminated portion with Ag. And a step of selectively removing the halogenated Ag by etching, and a step of heat-treating the substrate. 2. A sputter chamber for depositing a halogenated Ag, a sample can be transported from the sputter chamber without breaking the vacuum and without being exposed to light, and the halogenated Ag is exposed in a predetermined pattern. An exposure chamber having an exposure unit of Ag is provided, and a sample stage to which a bias can be applied, a mask having a predetermined pattern, and a monochromatic light source are sequentially arranged in the exposure chamber. Wiring forming device.