KR20060013121A - A method for depositing thin film using ald - Google Patents

Abstract

The present invention relates to an ALD thin film deposition method, comprising a first feeding step of feeding a first reaction source into a chamber on which a substrate is seated, a first purge step of purging the first reaction source from a chamber, and ALD thin film which deposits a thin film on a substrate by repeating a cycle consisting of a second feeding step of feeding a reaction source and a second purge step of purging by-products which do not react with or react with the first reaction source from the chamber. In the deposition method, at least one of the first feeding step, the first purging step, the second feeding step, and the second purging step is implemented through a discontinuous repetitive process.

Description

A method for depositing thin film using ALD}

1 is a graph showing a process sequence of a conventional ALD thin film deposition method,

2 is a graph showing a process sequence of a first embodiment of an ALD thin film deposition method according to the present invention;

3 is a graph showing a process sequence of a second embodiment of an ALD thin film deposition method according to the present invention;

4 is a graph showing a process sequence of a third embodiment of an ALD thin film deposition method according to the present invention;

5 is a graph showing a process sequence of a fourth embodiment of an ALD thin film deposition method according to the present invention;

6 is a graph showing a process sequence of a fifth embodiment of an ALD thin film deposition method according to the present invention;

<Description of Signs of Major Parts of Drawings>

S1 ... first feeding step

S2 ... first purge step

S3 ... second feeding step

S4 ... second purge step

S1a, S1b ... first subfeeding step

S2a, S2b ... first sub purge step

S3a, S3b ... second subfeeding step

S4a, S4b ... second sub-purge step

The present invention relates to an ALD thin film deposition method for depositing a thin film on a substrate by feeding or purging another kind of reaction source into a chamber in which the substrate is seated.

1 is a graph illustrating a process sequence of a conventional ALD thin film deposition method.

As shown, the ALD thin film deposition method includes a first feeding step of feeding a first reaction source into the chamber on which the substrate is seated, a first purge step of purging the first reaction source from the chamber, and a chamber The second feeding step of feeding the second reactant and the second purge step of purging the second reactant which does not react with the first reactant or by-products generated from the chamber are repeated several times as one cycle on the substrate. Deposit a thin film. When one cycle proceeds according to the above process sequence, one atomic layer or one molecular layer is formed on the substrate.

By the way, in manufacturing a semiconductor element, the surface area of the substrate on which the pattern is formed is several hundred percent or more larger than the surface area of the substrate on which the pattern is not formed. This is because the substrate surface area before the thin film deposition proceeds is increased by several hundred% or more as the pattern is formed. In this case, the reaction source with low vapor pressure did not sufficiently penetrate into the inside of the pattern such as a contact hole when not sufficiently fed into the chamber, and thus perfect thin film deposition did not proceed. Meant.

Thus, although it is necessary to heat the reaction source in order to increase the amount of vapor of the reaction source fed into the chamber, most of the metal organic reactants have a limit to raise the temperature because the decomposition temperature is low.

In addition, although there is a method of increasing the supply amount by lengthening the time when feeding the reaction source into the chamber, this resulted in a decrease in productivity.

Particularly in the case of the bubble type, since the reactants exist in the vapor state in the upper part of the canister containing the liquid reactants, the reactants already present in the vapor state at the time of initial feeding flow into the chamber at a time for a short time. Although supplied, the feeding time is lengthened since the liquid reactant must be converted into a vapor state and then supplied to the chamber. Therefore, even if the feeding time is increased, there is a problem that a large amount of reactants are not supplied to the chamber in proportion to the actually increased time.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an ALD thin film deposition method capable of supplying a large amount of reaction source to the chamber for a shorter time.

Another object of the present invention is to provide a time for the reaction source to react on the substrate to remove the by-products, so that the additionally supplied reaction source is penetrated to the inside of the contact hole, in order to maximize the reaction at the substrate surface. It is an object of the present invention to provide an ALD thin film deposition method capable of sufficient reaction.

In order to achieve the above object, the thin film deposition method according to the present invention,

A first feeding step of feeding a first reaction source into the chamber in which the substrate is seated, a first purging step of purging the first reaction source from the chamber, and a second feeding of a second reaction source into the chamber In the ALD thin film deposition method of depositing a thin film on the substrate by repeating a cycle consisting of a feeding step and a second purge step of purging by-products generated by not reacting or reacting with the first reaction source from the chamber, At least one or more of the first feeding step, the first purging step, the second feeding step, and the second purging step may be implemented through a discontinuous repetition process.

In the present invention, the first feeding step includes at least two first subfeeding steps, and the first purging step includes at least two first subpurge steps, wherein the first subfeeding step includes: The first sub purge steps are alternately performed. In this case, productivity may be improved by reducing the time between the first feeding step and the first purge step than the time between the second feeding step and the second purge step.

In the present invention, the second feeding step is composed of at least two second subfeeding steps, and the second purging step is composed of at least two second subpurge steps, wherein the second subfeeding step and the second subfeeding step are performed. The two sub purge steps are alternately performed.

In the present invention, the first feeding step includes at least two first subfeeding steps, and the first purging step includes at least two first subpurge steps, wherein the first subfeeding step includes: The first sub-purge step is performed alternately with each other, the second feeding step is composed of at least two second sub-feeding step, the second purge step is composed of at least two second sub-purge step, The second sub feeding step and the second sub purge step are alternately performed.

In the present invention, the first purge step and the second purge step use an inert gas such as Ar or N ₂ .

In order to achieve the above object, ALD thin film deposition method according to the present invention,

The first feeding step of feeding a first reaction source into the chamber while the inside of the chamber on which the substrate is seated, and the second feeding step of feeding a second reaction source into the chamber after the first feeding step. And depositing a thin film on the substrate by repeating a cycle consisting of a second purge step of purging a by-product generated by not reacting with or reacting with the first reaction source from the chamber. The first feeding step may include at least two first sub-feeding steps.

Hereinafter, ALD thin film deposition method according to the present invention will be described in detail with reference to the accompanying drawings.

As shown, the ALD thin film deposition method according to the present invention, the thin film is deposited on the substrate by repeating the cycle consisting of the first feeding step, the first purge step, the second feeding step, the second purge step In this case, at least one or more of the first feeding step, the first purging step, the second feeding step, and the second purging step may be implemented through a discontinuous repetition step. This will be described in detail as follows.

2 is a graph showing a process sequence of the first embodiment of the ALD thin film deposition method according to the present invention.

As shown, the first embodiment of the ALD thin film deposition method according to the present invention, the first feeding step (S1) for feeding the first reaction source into the chamber on which the substrate is seated, the first reaction source chamber A first purge step (S2) to purge from; a second feeding step (S3) to feed a second reactant into the chamber; and a second purge of by-products generated by not reacting with or reacting with the first reactant from the chamber. The thin film is deposited on the substrate by repeating the cycle consisting of the purge step (S4). When one cycle proceeds according to the above process sequence, one atomic layer or one molecular layer is formed on the substrate. At this time, an inert gas such as Ar or N ₂ is used as a gas for purging the chamber.

The first feeding step S1 is composed of at least two first subfeeding steps, and the first purging step S2 is composed of at least two first subpurge steps, wherein the first subfeeding step and the first subfeeding step are performed. The purge steps are performed alternately. In the present embodiment, for the sake of explanation, the first feeding step S1 includes two first subfeeding steps S1a and S1b, and the first purge step S2 also includes two first subpurge steps S2a. The two-step step composed of step S2b will be described as an example. However, this is only one embodiment, and of course, a multi step consisting of three or more substeps is also possible.

In the case of the first embodiment, the overall process sequence includes a first subfeeding step S1a-> a first subpurge step S2a-> a first subfeeding step S1b-> a first subpurge step S2b. The first feeding step S1 and the first purge step S2 are performed, and thereafter, the ALD process of one cycle is performed through the second feeding step S3-> second purging step S4.

In this way, by performing each of the first feeding step and the first purge step in two steps instead of one steps, a sufficient amount of reaction source can be supplied to the chamber in a relatively short time, and the surface reaction on the substrate Can be maximized. This embodiment is more effective in the case of a low vapor pressure reaction source, and more particularly in the case of generating the reaction source in a bubble manner.

A typical process module (PM) for performing the ALD thin film deposition method is composed of a reaction box (source box), the chamber, the gas box (gas box) for transferring the reaction source of the reaction source box to the chamber. At this time, the reaction source box is composed of a canister containing the reaction source of the liquid phase, the on / off valve mounted on the canister, the on / off valve is connected to the gas box line. The amount of reaction source steam generated through the on / off valve depends on the degree of vapor pressure of the reaction source or the degree of heating or cooling of the canister.

When the on / off valve is opened, the reaction source which is already in the vapor state inside the canister is supplied to the chamber abruptly, and then the supply amount is drastically reduced. This is because time is required until the reaction source in the liquid phase is converted into the gas phase. Therefore, even when the on / off valve is continuously opened, the amount of reaction source supplied to the chamber is not proportional to the opening time. Therefore, it is more effective to supply the reaction source in several portions as in the present embodiment, rather than supplying the reaction source for a long time at a time.

As such, by supplying the first reaction source in two steps and supplying it to the chamber, a larger amount of reaction source can be supplied for a shorter time. Therefore, even when there is a pattern such as a contact hole, sufficient thin film deposition can be expected. Can be.

In addition, by feeding the first reaction source as well as the purge in two steps, by-products formed by the first reaction source first supplied on the substrate can be removed twice on the substrate, and thus the second reaction source. It can maximize the surface reaction at the time of supply.

An example of depositing an HfO 2 thin film on a substrate by the ALD method will be described using the above example.

The HfO2 thin film formed by the ALD method is a thin film that has been widely studied as a capacitor thin film in DRAM devices and is being considered for mass production. However, in order to deposit HfO2 thin films, TEMAHf, Hf (t-BuO) or TDMAHf should be used as the first reaction source, and the vapor pressure of the first reaction source is considerably low (eg, TEMAHF 0.5 Torr at 70 deg C). Therefore, when the thin film is deposited using the first reaction source having a low vapor pressure, the amount of vapor supplied per unit time is small, so that the first reaction source is sufficiently penetrated into the contact hole having an aspect ratio of 20: 1 or more. It was very difficult to do

However, more efficient thin film deposition is possible by dividing the feed of the first reactant such as TEMAHf, Hf (t-BuO), TDMAHf, etc. in two steps and dividing the purge of the first reactant in two steps.

[Table 1] shows a conventional ALD thin film deposition method comprising a one-step first feeding step S1, a first purge step S2, a second feeding step and a second purge step, and a two-step first feeding step S1a. In the ALD thin film deposition method of the present invention consisting of (S1b) and the first purge step (S2a) (S2b), the second feeding step (S3) and the second purge step (S4) of one step was compared Table. Here, the first reaction source was TEMAHf, and the second reaction source was O3.

Referring to Table 1, the thickness of the thin film formed on the substrate was 29.94 kPa when the ALD thin film deposition method was carried out, and the thin film thickness was 30.76 kPa when the ALD thin film deposition method of the present invention was carried out. In the case of the present application, it can be seen that a large amount of the reaction source is supplied. And no significant difference was seen also in flatness.

TABLE 1

Process time (sec) Thickness Average Uniformity Conventional S1 / S2 / S3 / S4 29.94 1.5 Invention (2 step) (S1a) / (S2a) / (S1b) / (S2b) / (S3) / (S4) 30.76 1.88

3 is a graph showing a process sequence of a second embodiment of an ALD thin film deposition method according to the present invention.

As shown, the second embodiment of the ALD thin film deposition method according to the present invention, the first feeding step (S1 ') for feeding the first reaction source into the chamber on which the substrate is seated, and the first reaction source A first purge step S2 ′ purging from the chamber, a second feeding step S3 feeding a second reactant to the chamber, and a by-product generated by not reacting or reacting with the first reactant from the chamber; The thin film is deposited on the substrate by repeating the cycle consisting of the second purge step (S4). When one cycle proceeds according to the above process sequence, one atomic layer or one molecular layer is formed on the substrate. At this time, an inert gas such as Ar or N ₂ is used as a gas for purging the chamber.

In order to improve productivity, the time required to achieve the ALD cycle should be shortened. In the second embodiment, the time for performing the first feeding step and the first purge step can be reduced. In the case of the present invention, the multi-step of each of the first feeding step and the first purge step, in this embodiment, can be carried out in two steps, so that a larger amount of the first reactant supply and purge can be performed for a short time.

In the first embodiment, the total time during which the first feeding step S1a, S1b and the first purge step S2a, S2b proceeds, and the second feeding step S3 and the second purge step S4 proceed. In the second embodiment, the first feeding step S1a ', S1b' and the first purge step S2a ', S2b' are performed. By reducing the time period during which the second purge step S4 proceeds, productivity can be improved. This is because each of the first feeding step and the second purging step can be multi-stepped to feed and purge the first reaction source into the chamber for a shorter time.

4 is a graph showing a process sequence of a third embodiment of an ALD thin film deposition method according to the present invention.

As shown, the third embodiment of the ALD thin film deposition method according to the present invention, the first feeding step (S1) for feeding the first reaction source into the chamber on which the substrate is seated, and the first reaction source chamber A first purge step (S2) to purge from; a second feeding step (S3) to feed a second reactant into the chamber; and a second purge of by-products generated by not reacting with or reacting with the first reactant from the chamber. The thin film is deposited on the substrate by repeating the cycle consisting of the purge step (S4). When one cycle proceeds according to the above process sequence, one atomic layer or one molecular layer is formed on the substrate. At this time, an inert gas such as Ar or N ₂ is used as a gas for purging the chamber.

The second feeding step S3 is composed of at least two second subfeeding steps, and the second purging step is composed of at least two second subpurge steps, wherein the second subfeeding step and the second subpurge step are performed. Are carried out alternately. In the present embodiment, for the sake of explanation, the second feeding step S3 includes two second subfeeding steps S3a and S3b, and the second purge step S4 also includes two second subpurge steps S4a. The two-step step composed of step S4b will be described as an example. However, this is also only one embodiment and of course also possible in a multi-step.

In the case of the second embodiment, the overall process sequence includes a second subfeeding step S3a-> a second subpurge step S4a-> a second subfeeding step S3b-> a second subpurge step S4b. The second feeding step S3 and the second purge step S4 are performed, and thereafter, the ALD process of one cycle is performed through the first feeding step S1-> first purging step S2.

5 is a graph illustrating a process sequence of a fourth embodiment of an ALD thin film deposition method according to the present invention.

As shown, the fourth embodiment of the ALD thin film deposition seed according to the present invention, the first feeding step (S1) for feeding the first reaction source into the chamber on which the substrate is seated, and the first reaction source chamber A first purge step (S2) to purge from; a second feeding step (S3) to feed a second reactant into the chamber; and a second purge of by-products generated by not reacting with or reacting with the first reactant from the chamber. The thin film is deposited on the substrate by repeating the cycle consisting of the purge step (S4). When one cycle proceeds according to the above process sequence, one atomic layer or one molecular layer is formed on the substrate. At this time, an inert gas such as Ar or N ₂ is used as a gas for purging the chamber.

At this time, the first feeding step (S1) is composed of at least two first sub-feeding step, the first purge step (S2) is composed of at least two first sub-purge step, the first sub-feeding step and the first One sub-purge step is performed alternately. In addition, the second feeding step (S3) is composed of at least two second sub-feeding step, the second purge step (S4) is composed of at least two second sub-purge step, the second sub-feeding step ( S3a) S3b and the second sub purge step S4a and S4b are alternately performed.

In the case of the third embodiment, the overall process sequence is the first sub-feeding step (S1a)-> the first sub-purging step (S2a)-> the first sub-feeding step (S1b)-> the first sub-purging step (S2b) Through the first feeding step (S1) and the first purge step (S2) through the second sub-feeding step (S3a)-> second sub-purging step (S4a)-> second sub-feeding step (S3b) A second process of ALD is performed by performing the second feeding step S3 and the second purging step S4 through the second sub-purging step S4b.

6 is a graph showing a process sequence of a fifth embodiment of an ALD thin film deposition method according to the present invention.

As shown, the fifth embodiment of the ALD thin film deposition seed according to the present invention,

While the inside of the chamber on which the substrate is seated, the first feeding step (S1) for feeding the first reaction source into the chamber, the second feeding step (S3) for feeding the second reaction source into the chamber, and the chamber The thin film is deposited on the substrate by repeating the cycle consisting of a second purge step (S4) for purging by-products which do not react with or react with the first reaction source. In this case, the pumping step (S ") is performed by operating a vacuum pump without using an inert gas such as Ar or N ₂ , the puncturing step (S") is to remove the by-products on the substrate of the next supply source Maximize surface response. In this case, the first feeding step S1 includes at least two first subfeeding steps. In the present embodiment, for the sake of explanation, the first feeding step S1 is an example of a two-step step consisting of two first subfeeding steps S1a and S1b. However, this is only one embodiment, and of course, a multi step consisting of three or more substeps is also possible.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

As described above, according to the thin film deposition method according to the present invention, the feeding step is divided into two or more steps, so that a large amount of reaction source can be supplied to the chamber for a shorter time, so that there is a pattern such as a large aspect ratio contact hole. In this case, sufficient thin film deposition can be expected.

In addition, since not only the feeding step but also the purge step is divided into two or more steps, the by-product formed by the first reaction source supplied on the substrate can be removed twice on the substrate, and thus the surface during the supply of the next reaction source can be removed. Maximize the reaction.

Claims (7)

A first feeding step of feeding a first reaction source into the chamber in which the substrate is seated, a first purging step of purging the first reaction source from the chamber, and a second feeding of a second reaction source into the chamber In the ALD thin film deposition method of depositing a thin film on the substrate by repeating a cycle consisting of a feeding step and a second purge step of purging by-products generated by not reacting or reacting with the first reaction source from the chamber, At least one of the first feeding step, the first purging step, the second feeding step, and the second purging step is implemented through a discontinuous repetitive process. The method of claim 1, The first feeding step is composed of at least two first sub-feeding steps, The first purge step is composed of at least two first sub-purge step, wherein the first sub-feeding step and the first sub-purge step are performed alternately with each other, The method of claim 2, ALD thin film deposition method, characterized in that to improve the productivity by reducing the time the first feeding step and the first purge step proceeds than the time of the second feeding step and the second purge step. The method of claim 1, The second feeding step is composed of at least two second sub-feeding steps, The second purge step includes at least two second sub-purge steps, wherein the second sub-feeding step and the second sub-purge step are performed alternately with each other. The method of claim 1, The first feeding step includes at least two first subfeeding steps, and the first purge step includes at least two first subpurge steps, wherein the first subfeeding step and the first subpurge step are performed. Are carried out alternately, The second feeding step includes at least two second subfeeding steps, and the second purge step includes at least two second subpurge steps, wherein the second subfeeding step and the second subpurge step are performed. ALD thin film deposition method characterized in that the alternately performed. The method according to any one of claims 1 to 5, The first purge step and the second purge step, ALD thin film deposition method characterized in that using an inert gas such as Ar or N ₂ gas. While popping inside the chamber where the substrate is seated, A first feeding step of feeding a first reaction source into the chamber, a second feeding step of feeding a second reaction source into the chamber after the first feeding step, and reacting with the first reaction source from the chamber In the ALD thin film deposition method of depositing a thin film on the substrate by repeating the cycle consisting of a second purge step of purging the by-products generated by the reaction or not The first feeding step, ALD thin film deposition method comprising at least two first sub-feeding step.

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