KR100508755B1 - Method of forming a thin film having a uniform thickness in a semiconductor device and Apparatus for performing the same - Google Patents

Abstract

A method and apparatus for forming the semiconductor thin film uniformly are disclosed. A gas required for thin film formation is introduced in a first direction in the process chamber to form a first thin film. The gas may be introduced onto the first thin film in a direction opposite to the first direction to form a second thin film capable of compensating for nonuniformity in the thickness of the first thin film. Such a process may be repeatedly performed to form a thin film having a uniform thickness.

Description

Method of forming a thin film having a uniform thickness in a semiconductor device and Apparatus for performing the same

The present invention relates to chemical vapor deposition (CVD) and atomic layer deposition (ALD) and to a device suitable for carrying out the same, and more particularly, to a method for forming a uniform film in a semiconductor device and to perform the same. A device suitable for doing so.

In order to obtain a large inventory of wafers and a low inventory of productivity and low power consumption, the design rule of the device is reduced, thereby increasing the density of semiconductor devices. In order to cope with such an increase in density, a technology of forming a thin film has been steadily developed. The thin film forming technology can be roughly classified into chemical vapor deposition and atomic layer deposition. In particular, in recent years, many atomic layer deposition techniques for controlling thin film formation in atomic layer units have been developed. It is still used as an essential process.

Chemical vapor deposition is a process in which a precursor in a gaseous or plasma state is moved to a wafer surface to form a solid nuclei by a chemical reaction on the wafer surface, and the nucleus is grown to form a thin film.

There are two main types of chemical vapor deposition exhausts to accomplish this.

The first is to introduce process gas from the top of the center of the chamber and through the shower head to distribute the process gas uniformly throughout the wafer. This type of exhaust has the advantage of uniformly distributing the process gas over the entire surface of the wafer, but since the exhaust should be located on the side of the chamber, gaseous by-products and impurities of the chemical reaction are not uniformly removed, thereby degrading the characteristics of the thin film. Cause.

Second, the process gas is introduced horizontally from the side of the chamber to the wafer surface to form the thin film by flowing the process gas in a specific one direction. In this type, a thicker film is formed near the gas supply unit into which the process gas is introduced, and a thinner film is formed as the distance from the gas supply unit increases. This non-uniformity of thin film thickness causes a loading effect. That is, an etching process for forming a pattern after the deposition process of the thin film is performed, and the etching rate and the etching profile are nonuniform depending on the thickness of the thin film during the etching process. As a result, an over-etched portion may occur, which may cause a defect in characteristics of the semiconductor device.

In atomic layer deposition, a source gas is adsorbed onto a wafer surface, and then the wafer surface is purged with a purge gas, and a reaction gas is introduced to cause a chemical reaction with the source gas to form an atomic layer. After the reaction is completed, the unreacted material and impurities are purged using purge gas. As a result, the atomic layer deposition method can control the formation of the thin film in atomic units, and the thickness of the thin film can be controlled more precisely, so that the aspect ratio can be improved when the pattern density is high.

In the exhaust part performing the atomic layer deposition method, since the exhaust part should be located at the side of the chamber in the type using the shower head, the by-products, unreacted substances and impurities due to the reaction are not uniformly removed as in the chemical vapor deposition. In the traveling wave type, the direction of gas supply is parallel to the wafer surface, and the direction of purging unreacted gas and impurities is also the same as the gas supply direction, so that the purge process is smooth, but close to the gas supply part. It has a problem of bringing uneven thickness of thin film between and far away.

Several methods have been developed to solve these problems.

The first is to supply and purge sufficient reactant. In other words, the total cycle time is increased in atomic layer deposition so that the reactants are sufficiently supplied throughout the wafer. In this case, however, the unit process time increases, which leads to a decrease in throughput of the process, which is not suitable for the actual production process.

The second is to rotate the support that supports the wafer in the reaction section. Using this method, the thickness uniformity of the thin film can be obtained and there is no problem in purging of unreacted gas and impurities, but an additional motor system for rotating the support at a constant linear speed should be employed. If a multi wafer type or wafer cassette needs to be rotated, multiple motor systems must be employed or the motor system must be quite large in power. When the power of the motor system increases, vibration of the entire exhaust portion is generated, which causes a lot of constraints.

The third is to flow the reactants in opposite directions. In other words, the supply and purge of the source gas are in the first direction, and the supply and purge of the reaction gas are in the second direction opposite to the first direction. In this way, when the deposition of the first atomic layer is completed, the process is repeated in the same manner. However, such a method can purge different kinds of gases to different exhaust parts, thereby realizing rapid exhaustion, and effectively remove impurities remaining during thin film formation, but cannot be a means of securing the uniformity of the thin film. That is, according to the above method, an excessive thinning of the source gas and a shortening of the reaction gas, or a shortage of the source gas and an excessive amount of the reactant gas are caused according to the direction in which the gas flows, thereby making it impossible to obtain a uniform thin film thickness.

1A to 1D show the thickness of a thin film along a traveling direction of the gases. When using the above-described prior art, it has a thickness of the thin film as shown in Figure 1b to 1d. It is determined according to the type, temperature, pressure, process execution time, etc. of the thin deposition gas having any of the above-described form of FIGS. 1B to 1D.

Therefore, as shown in FIG. 1A, forming a thin film having a uniform thickness without being affected by the direction of deposition gas will be required to improve the characteristics of the semiconductor device and to reduce the defective rate.

Therefore, the present invention is designed to solve the above problems, the first object of the present invention is to provide a chemical vapor deposition method for obtaining a uniform thin film thickness.

It is a second object of the present invention to provide a chemical vapor deposition apparatus suitable for performing the chemical vapor deposition method.

It is a third object of the present invention to provide an atomic layer deposition method for obtaining a uniform thin film thickness.

It is a fourth object of the present invention to provide an atomic layer deposition apparatus suitable for realizing the above atomic layer deposition method.

The present invention for achieving the first object, the step of forming a first thin film on the surface of the substrate by introducing a first process gas in a first direction horizontal to the substrate in the reaction space; And forming a second thin film on the surface of the first thin film by introducing a second process gas in a second direction horizontal to the substrate and opposite to the first direction.

In order to achieve the second object of the present invention, the present invention is a chamber having a reaction space for receiving a substrate; A first gas supply unit for introducing a first process gas in a first direction horizontal to the substrate; And a second gas supply unit for introducing a second process gas in a second direction horizontal to the substrate and opposite to the first direction.

In order to achieve the third object, the present invention includes the steps of adsorbing the first source gas on the surface of the substrate by introducing a first source gas in a first direction horizontal to the substrate in the reaction space; Purging the unsorbed first source gas using the first purge gas in the first direction; Introducing a first reaction gas in the first direction to react the first source gas adsorbed on the surface of the substrate with the first reaction gas to form a first atomic layer; Purging reaction byproducts and unreacted first reaction gas using a second purge gas in the first direction; Adsorbing the second source gas to the surface of the first atomic layer by introducing a second source gas in a second direction horizontal to the substrate and opposite to the first direction; Purging the unadsorbed second source gas using a third purge gas in the second direction; Introducing a second reaction gas in the second direction to react the second source gas adsorbed on the first atomic layer with the second reaction gas to form a second atomic layer; And purging the reaction by-product and the unreacted second reaction gas using a fourth purge gas in the second direction.

In order to achieve the fourth object of the present invention, the present invention comprises a chamber having a reaction space for receiving a substrate; A first gas supply unit for introducing a first source gas, a first reaction gas, a first purge gas, and a second purge gas into a first direction horizontal to the substrate; A first exhaust unit for purging unadsorbed material, unreacted material and impurities using the first purge gas and the second purge gas in the first direction; A second gas supply unit for introducing a second source gas, a second reaction gas, a third purge gas, and a fourth purge gas into a second direction horizontal to the substrate and opposite to the first direction; And a second exhaust unit for purging the unreacted material, the unadsorbed material, and the impurities using the third purge gas and the fourth purge gas in the second direction.

In particular, atomic layer deposition uses a chemical reaction such as chemical vapor deposition, but is distinguished from chemical vapor deposition in that each gas flows in one pulse without being mixed in the chamber. When using the atomic layer deposition method, the atoms occupy a stable position from the time of deposition, and when crystallization of the thin film is required in the post-process, the crystallization temperature is lowered compared to the chemical vapor deposition method because the crystallization is shown to some extent immediately after the deposition. Have

In general, atomic layer deposition includes loading a semiconductor substrate for performing a process; Supplying and adsorbing the source gas in the form of a pulse; Purging unadsorbed source gas; Supplying the reaction gas in pulse form to form an atomic layer; And purging the unreacted reaction gas. In addition, the thickness of the thin film can be adjusted by atomic layer due to the repetition of the process, and the aspect of the control can be obtained by adjusting the number of repetitions of the deposition process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1

2 and 3 are schematic and timing diagrams of an apparatus for explaining a chemical vapor deposition method according to a first embodiment of the present invention.

2 is a schematic diagram of a chemical vapor deposition apparatus for introducing a process gas in two directions. Referring to FIG. 2, a first gas supply unit 101 for introducing a process gas in a first direction 105 is located at a side of the chamber 100, and the first gas supply unit is formed at the center of the chamber 100. The second exhaust part 104 is located in the same direction as the 101. As a result, when viewed from the wafer introduced into the chamber, the first gas supply unit 101 and the second exhaust unit 104 are located in pairs. The second gas supply unit 103 for introducing the process gas in the second direction 106 is located in a direction facing the first gas supply unit 101 and is disposed in pairs with the first exhaust unit 102.

In addition, the chamber 100 is not limited to the shape of a rectangle as shown in FIG. 2, and if the chamber has gas supply parts and exhaust parts facing each other in the chamber, the present invention can be easily implemented.

3 is a timing diagram for explaining a chemical vapor deposition method for introducing a process gas in two directions. Referring to FIG. 3, a process gas is introduced in a first direction from a first gas supply in a horizontal direction of a wafer. In this case, a chemical reaction occurs on the upper surface of the wafer to form a first thin film having a predetermined thickness, and the thickness of the formed first thin film becomes closer to the first gas supply part. Subsequently, a process gas is introduced from the second gas supply part in a second direction that is opposite to the first direction while being horizontal in the wafer. At this time, a chemical reaction occurs on the upper surface of the first thin film formed on the wafer surface to form a second thin film having a predetermined thickness. As the second thin film is closer to the second gas supply part, the second thin film becomes thicker, and thus, a thin film having a uniform thickness is formed by compensating for thickness unevenness of the first thin film.

The time in which the process gas is introduced in the first direction is t ₁ , and the time in which the process gas is introduced in the second direction is t ₂ . The times t ₁ and t ₂ are variable according to the detailed process conditions, and are variables that can be easily changed and applied by those skilled in the art. It can also be seen that the process can be performed repeatedly.

Example 2

4 and 5 are schematic and timing diagrams of an exhaust unit for explaining a chemical vapor deposition method according to a second embodiment of the present invention.

4 is a schematic diagram of an apparatus for introducing a process gas in four directions to form a thin film of uniform thickness. Referring to FIG. 4, a first gas supply unit (not shown) for introducing a process gas in the first direction 110 is located at a side of the chamber, and is formed in the same direction as the first gas supply unit at the center of the chamber. 3 Exhaust (not shown) is located. As a result, when viewed from the wafer introduced into the chamber, the first gas supply portion and the third exhaust portion are paired. A second gas supply unit (not shown) for introducing the process gas in the second direction 111 is positioned in a direction of 90 ° with the first gas supply unit, and is paired with a fourth exhaust unit (not shown). Also, a third gas supply unit (not shown) and a first exhaust unit (not shown) for introducing a process gas in a third direction 112 in a direction facing the pair of the first gas supply unit and the third exhaust unit inside the chamber. And a fourth gas supply unit (not shown) and a second exhaust unit (not shown) for introducing the process gas in the fourth direction 113 in a direction facing the pair of the second gas supply unit and the fourth exhaust unit. Not located).

In addition, the chamber is not limited to the shape of a quadrangle as shown in FIG. 4, and the present invention may be implemented as long as the chamber has gas supply parts and exhaust parts facing each other.

5 is a timing diagram for explaining a chemical vapor deposition method for introducing a process gas in four directions. Referring to FIG. 5, process gases are sequentially introduced in four directions. First, the process gas is introduced in the first direction from the first gas supply in the horizontal direction of the wafer. In this case, a chemical reaction occurs on the upper surface of the wafer to form a first thin film having a predetermined thickness, and the thickness of the formed first thin film becomes closer to the first gas supply part. The process gas is then introduced from the second gas supply in a second direction that is horizontal to the wafer and perpendicular to the first direction. At this time, a chemical reaction occurs on the upper surface of the first thin film formed on the wafer surface to form a second thin film having a predetermined thickness. The second thin film becomes thicker closer to the second gas supply. The process gas is introduced from the third gas supply in a third direction that is horizontal to the wafer and opposite the first direction. At this time, a chemical reaction occurs on the upper surface of the second thin film formed on the wafer surface to form a third thin film having a predetermined thickness. The third thin film becomes thicker closer to the third gas supply. The process gas is introduced from the fourth gas supply in a fourth direction that is horizontal to the wafer and opposite the second direction. At this time, a chemical reaction occurs on the upper surface of the third thin film formed on the wafer surface to form a fourth thin film having a predetermined thickness. The fourth thin film becomes thicker closer to the fourth gas supply.

Due to the sequential formation of the first thin film, the second thin film, the third thin film, and the fourth thin film as described above, a thin film having a uniform thickness can be formed as a result.

In addition, the order of forming the thin film is not limited to the order of the first thin film, the second thin film, the third thin film, and the fourth thin film, and each thin film forming process needs to be performed only once during one cycle. The cycle can of course be repeated several times.

The time for introducing the process gas in the first direction is t ₁ , the time for introducing the process gas in the second direction is t ₂ , the time for introducing the process gas in the third direction is t ₃ , and the process in the fourth direction. The time at which the gas is introduced is t ₄ . The time t ₁ , t ₂ , t ₃ , t ₄ is variable according to the detailed process situation, and is a variable that can be easily changed and applied by those skilled in the art. It can also be seen that the process can be performed repeatedly.

According to the first and second embodiments described above, deposition of a silicon film, deposition of a dielectric film, deposition of a metal film, and the like are possible.

For example, in the case of silicon deposition, SiH ₄ , SiCl ₂ H ₄ are used to deposit polycrystalline silicon, and SiCl ₃ H, SiCl ₄ , SiH ₄ / O _2, and the like are used to form an epi layer.

In the case of the deposition of the dielectric film, there are an oxide film, a nitride film, and the like. The oxide film is formed using a metal precursor and an oxidant, and the nitride film is formed using a metal precursor and a nitride. The oxidizing agent may be O ₂ , plasma-O ₂ , remote plasma O ₂ , O _3, etc., and nitriding agents include NH ₃ , plasma-N ₂ , plasma-NH ₃ , and remote plasma N ₂ .

Examples of oxide films deposited using metal precursors include SrO, BaO, Y ₂ O ₃ , La ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , Al ₂ O ₃ , SiO ₂ , GeO ₂ and SrTiO ₃ , BaTiO ₃ , PbZrO ₃ , and the like, and examples of the nitride film deposited using a metal precursor include Si ₃ N ₄ , TiN, TaN, AlN, and WN.

As an example of dielectric film deposition, there is one in which Ta (OC ₂ H ₅ ) ₅ , which is a precursor of Ta, is reacted with O ₂ , which is an oxidant, to form a Ta ₂ O ₅ dielectric film. At this time, vaporized Ta (OC ₂ H ₅ ) ₅ is supplied to the reaction chamber through a gas supply unit by a carrier gas such as N ₂ , He, Ar, or the like. At this time, the oxidant is simultaneously supplied to the reaction chamber through a predetermined supply line to form a Ta ₂ O ₅ dielectric film. At this time, a deposition temperature of 300 ° C to 500 ° C is appropriate and maintains a pressure of 10torr or less. At this time, the deposition thickness increases in proportion to the deposition time.

Examples of metals deposited in metal deposition include W, Al, Cu, Ru, Ti, and the like. Looking at the reaction scheme for some of the metals,

WF ₆ + 3H ₂ → W + 6HF

The reaction is performed as Al ₂ (CH ₃ ) ₆ + 2H ₂ → C ₂ H ₆ + 2Al + 4CH ₄ .

As another composite film, for example, SiG ₄ may be formed by reacting SiH ₄ with GeH ₄ . Looking at the reaction scheme of the composite membrane,

React as SiH ₄ + GeH ₄ → SiGe.

Example 3

6 and 7 are schematic and timing diagrams of the atomic layer deposition apparatus for explaining the atomic layer deposition method according to the third embodiment of the present invention.

6 is a schematic view of an atomic layer deposition apparatus for introducing and purging process gases in two directions. Referring to FIG. 6, a first gas supply unit 202 for introducing and purging source gas and reaction gas in a first direction 206 is located at the side of the chamber 201, and is formed at the center of the chamber. The second exhaust part 205 is located in the same direction as the first gas supply part 202. As a result, when viewed from the wafer introduced into the chamber 201, the first gas supply part 202 and the second exhaust part 205 are located in pairs. The second gas supply unit 203 for introducing and purging the source gas and the reaction gas in the second direction 207 is located in a direction facing the first gas supply unit, and is paired with the first exhaust unit 204. Will be located.

 In addition, the chamber is not limited to the rectangular shape as shown in FIG. 6, and the present invention can be implemented as long as the chamber has gas supply parts and exhaust parts facing each other.

7 is a timing diagram for explaining an atomic layer deposition method for introducing and purging a source gas and a reaction gas in two directions. Referring to FIG. 7, source gas is introduced in a first direction from a first gas supply in a horizontal direction of a wafer. At this time, a chemical adsorption occurs on the wafer surface to form a layer, and then purge gas is introduced in the first direction to purify the upper surface of the wafer. The non-chemisorbed source gas is then removed from the chamber, leaving a chemisorbed layer of undamaged source gas on the wafer. Next, a reaction gas is introduced into the chamber in the first direction. The reaction gas chemically reacts with the chemisorbed source gas to form a first atomic layer on the surface of the wafer. That is, the source gas and the reaction gas react on the wafer surface to form a first thin film in atomic layer units. After purging the surface of the first atomic layer using purge gas, source gas is introduced in a second direction opposite to the first direction. In this case, chemical adsorption occurs on the surface of the first atomic layer to form a layer, and then purge gas is introduced in the second direction to purify the upper surface of the first atomic layer. At this time, the source gas that has not been chemisorbed is removed from the chamber so that a chemisorbed layer of the intact source gas remains on the first atomic layer. Next, a reaction gas is introduced into the chamber in the second direction. The reaction gas chemically reacts with the chemisorbed source gas to form a second atomic layer on the surface of the first atomic layer. That is, the source gas and the reaction gas react on the wafer surface to form a second thin film in atomic layer units.

As a result, if a plurality of processes as described above are repeated, a thin film having a uniform thickness can be formed.

The time in which the source gas is introduced in the first direction is t ₁ , the time in which the purge gas is introduced in the first direction is t ₂ , t ₄ , and the time in which the reaction gas is introduced in the first direction is t ₃ . . The time for introducing the source gas in the second direction is t ₅ , the time for introducing the purge gas in the second direction is t ₆ , t ₈ , and the time for introducing the reaction gas in the second direction is t ₇ . . The time t ₁ to t ₈ is variable according to the detailed process situation, and is a variable that can be easily changed and applied by those skilled in the art. It can also be seen that the process can be performed repeatedly.

Example 4

8 and 9 are schematic and timing diagrams of the atomic layer deposition apparatus for explaining the atomic layer deposition method according to the fourth embodiment of the present invention.

8 is a conceptual diagram of an atomic layer deposition exhaust unit for introducing and purging a source gas and a reaction gas in four directions. A first gas supply unit (not shown) for introducing and purging the source gas and the reaction gas in the first direction 211 and 212 is located at the side of the chamber, and is located in the same direction as the first gas supply unit at the center of the chamber. A third exhaust portion (not shown) is located. As a result, when viewed from the wafer introduced into the chamber, the first gas supply portion and the third exhaust portion are paired. A second gas supply unit (not shown) for introducing and purging the source gas and the reaction gas in the second directions 213 and 214 is located in a direction of 90 ° with the first gas supply unit, and a fourth exhaust unit (not shown). Pairs). In addition, a third gas supply unit (not shown) for introducing and purging the source gas and the reaction gas in the third direction 215 and 216 in a direction facing the pair of the first gas supply unit and the third exhaust unit in the chamber. A fourth exhaust part (not shown) is located, and the fourth gas is used to introduce and purge the source gas and the reaction gas in the fourth direction 217 and 218 in a direction facing the pair of the second gas supply part and the fourth exhaust part. The gas supply unit (not shown) and the second exhaust unit (not shown) are positioned.

In addition, the chamber is not limited to the shape of a rectangle as shown in FIG. 8, and the present invention may be implemented as long as the chamber has gas supply parts and exhaust parts facing each other.

FIG. 9 is a timing diagram illustrating an atomic layer deposition method for introducing and purging a source gas and a reaction gas in four directions. 9, source gas, reaction gas, and purge gas are sequentially introduced in four directions. The source gas is introduced in the first direction from the first gas supply in the horizontal direction of the wafer. At this time, a chemical adsorption occurs on the wafer surface to form a layer, and then purge gas is introduced in the first direction to purify the upper surface of the wafer. The non-chemisorbed source gas is then removed from the chamber, leaving a chemisorbed layer of undamaged source gas on the wafer. Next, a reaction gas is introduced into the chamber in the first direction. The reaction gas chemically reacts with the chemisorbed source gas to form a first atomic layer on the surface of the wafer. That is, the source gas and the reaction gas react on the wafer surface to form a first thin film in atomic layer units.

After purging the surface of the first atomic layer using purge gas, source gas is introduced into a second direction that is horizontal to the wafer and perpendicular to the first direction. In this case, chemical adsorption occurs on the surface of the first atomic layer to form a layer, and then purge gas is introduced in the second direction to purify the upper surface of the first atomic layer. At this time, the source gas that has not been chemisorbed is removed from the chamber so that a chemisorbed layer of the intact source gas remains on the first atomic layer. Next, a reaction gas is introduced into the chamber in the second direction. The reaction gas chemically reacts with the chemisorbed source gas to form a second atomic layer on the surface of the first atomic layer. That is, the source gas and the reaction gas react on the wafer surface to form a second thin film in atomic layer units.

After purging the surface of the second atomic layer using purge gas, source gas is introduced into a third direction that is horizontal to the wafer and opposite to the first direction. At this time, chemical adsorption occurs on the surface of the second atomic layer to form a layer, and then purge gas is introduced in the third direction to purify the upper surface of the second atomic layer. At this time, the source gas that has not been chemisorbed is removed from the chamber so that a chemisorbed layer of the intact source gas remains on the second atomic layer. Next, a reaction gas is introduced into the chamber in the third direction. The reaction gas chemically reacts with the chemisorbed source gas to form a third atomic layer on the surface of the second atomic layer. That is, the source gas and the reaction gas react on the wafer surface to form a third thin film in atomic layer units.

After purging the surface of the third atomic layer by using purge gas, source gas is introduced in a fourth direction that is horizontal to the wafer and opposite to the second direction. In this case, chemical adsorption occurs on the surface of the third atomic layer to form a layer, and then purge gas is introduced in the fourth direction to purify the upper surface of the third atomic layer. At this time, the source gas which has not been chemisorbed is removed from the chamber, so that the chemisorbed layer of the source gas which is not damaged remains on the third atomic layer. Next, a reaction gas is introduced into the chamber in the fourth direction. The reaction gas chemically reacts with the chemisorbed source gas to form a fourth atomic layer on the surface of the third atomic layer. That is, the source gas and the reaction gas react on the wafer surface to form a fourth thin film in atomic layer units.

Due to the sequential formation of the first thin film, the second thin film, the third thin film, and the fourth thin film as described above, a thin film having a uniform thickness can be formed as a result. In addition, if a plurality of sequential process cycles described above are repeated, a thin film having a uniform thickness may be formed.

In addition, the order of forming the thin film is not limited to the order of the first thin film, the second thin film, the third thin film, and the fourth thin film, and each thin film forming process needs to be performed only once in one cycle. The cycle can of course be repeated several times.

The time in which the source gas is introduced in the first direction is t ₁ , the time in which the purge gas is introduced in the first direction is t ₂ , t ₄ , and the time in which the reaction gas is introduced in the first direction is t ₃ . . The time for introducing the source gas in the second direction is t ₅ , the time for introducing the purge gas in the second direction is t ₆ , t ₈ , and the time for introducing the reaction gas in the second direction is t ₇ . . The time in which the source gas is introduced in the third direction is t ₉ , the time in which the purge gas is introduced in the third direction is t ₁₀ , t ₁₂ , and the time in which the reaction gas is introduced in the third direction is t ₁₁ . . The time for introducing the source gas in the fourth direction is t ₁₃ , the time for introducing the purge gas in the second direction is t ₁₄ , t ₁₆ , and the time for introducing the reaction gas in the fourth direction is t ₁₅ . . The time t ₁ to t ₁₆ is variable according to the detailed process conditions, and is a variable that can be easily changed and applied by those skilled in the art. It can also be seen that the process can be performed repeatedly.

According to the third and fourth embodiments described above, deposition of a silicon film, deposition of a dielectric film, deposition of a metal film, and the like may be performed. More specifically, the deposited material may be a gate oxide film, a capacitor oxide film, a barrier film, a gate electrode, or a capacitor electrode. Source gas and reaction gas may vary depending on the recognition.

The gate oxide or capacitor oxide includes ZrO ₂ , HfOx, Ta ₂ O ₅ , Al ₂ O ₃ , TiOx, Ta ₂ O ₅ , BST, STO, PZT, Al ₂ O _3, etc. , Ta / TaN, TiSiN, TaSiN, and the like, and the gate electrode or capacitor electrode material includes TiN, WN, W, Pt, Ir, Ru, and the like.

Specifically, an example of depositing HfO ₂ using an Hf precursor containing an amino group and an oxidizing agent will be given.

A substrate, such as a silicon wafer, is first placed in a chamber maintained at a temperature of about 100 ° C to 500 ° C, preferably 150 ° C to 350 ° C, and the chamber is then evacuated to about 0.4torr. The source gas, which forms a thin film using an inert carrier gas such as argon or nitrogen, has a first direction above the substrate in the chamber at a flow rate of about 50 sccm (standard cubic centimeter per minute) to 5 slm (standard litter per minute), preferably 1000 sccm. Is introduced for 1 to 3 seconds. The source gas has an Hf element constituting a thin film and an amino group as a ligand group. Examples of the source gas include TEMAH (tetrakis-ethyl-amino-Halfnium, Hf [NC ₂ H ₅ CH ₃ ] ₄ ), TDEAH (tetrakis-diethyl-amino-Halfnium, Hf [N (C ₂ H ₅ ) ₂ ] ₄ ), TDMAH (tetrakis-dimethyl-amino-halfnium, Hf [N (CH ₃ ) ₂ ] ₄ ), and the like.

During this introduction of the source gas, the first portion of the source gas is chemisorbed onto the substrate to form a layer on the surface of the substrate. At this time, the second portion of the source gas is physically adsorbed on the upper portion, and the source gas is loosely coupled to the chemisorbed layer. The chamber is then purged or vacuum purged for about 1 second to 20 seconds, preferably 1 second to 4 seconds in the first direction using an inert gas such as argon or nitrogen. During the purge step, the non-chemisorbed source gas is removed from the chamber, leaving a chemisorbed layer of undamaged source gas on the substrate.

Next, a reaction gas containing an oxidant is introduced into the chamber in the first direction. The reaction gas is introduced for 2 to 5 seconds at a flow rate of 500 sccm. Then, the chemisorbed source gas and the reaction gas are chemically reacted to form an HfO ₂ atomic layer on the surface of the substrate. That is, Hf forming the source gas and oxygen forming the reaction gas react on the substrate to form a first HfO ₂ thin film in atomic layer units.

The source gas includes an oxidant comprising an activated oxidant or a hydroxyl group capable of forming oxygen radicals. For example, the activated oxidant is any one of ozone (O ₃ ), plasma O ₂ , remote plasma O ₂ , or plasma N ₂ O formed by a plasma generator. When O ₃ is formed by treating oxygen gas through an ozone generator, a portion of the O ₂ gas is converted into O ₃ to obtain ozone gas. The obtained ozone gas consists of oxygen gas and O ₃ gas, and the O ₃ gas is included in the ozone gas in a molar ratio of about 5% to 15%. In addition, the oxidizing agent including the hydroxyl group is H ₂ O or H ₂ O ₂ and the like.

Next, purge and vacuum purge the inert gas such as argon, nitrogen, etc. in the first direction in the first direction for about 1 to 20 seconds, preferably 1 to 4 seconds, so that unreacted reaction gases and reaction by-products are removed from the chamber. Removed.

If such a progress, then the process in the second direction in the chamber a second HfO ₂ thin film of atom layer unit is formed in the upper surface of claim 1 HfO ₂ thin film of atom layer unit.

Thereafter, the same process as above is repeated at regular intervals with different injection directions of gases.

Repeating the above-described process a plurality of times can form a thin film of uniform thickness.

When the thin film is formed according to the present invention as described above, it is possible to obtain the thickness of the thin film and the uniformity of the electrical characteristics.

In order to verify the effect of the present invention, in order to form the same type of thin film, the source gas is supplied and purged in the first direction according to the atomic layer deposition method, and the reaction gas is in the second direction opposite to the first direction. It is simulated based on the method of supplying and purging the third embodiment of the present invention shown in Figures 3 and 4.

In the conventional method, the deposition rate is 1 μs / cycle, the uniformity of the deposition thickness (range / (2 × average thickness) × 100) is assumed to be 5%, and the pattern loading phenomenon is performed at the starting point in the first direction. 100%, 50% at the endpoint, and step coverage are assumed to be the same, 100% at all locations. Hereinafter, the starting point of the first direction will be referred to as a starting point, and the ending point of the first direction will be referred to as an end point. That is, the starting point becomes the end point of the second direction, and the end point becomes the starting point of the second direction.

 Deposition thickness and uniformity according to the conventional method and the present invention> cycle starting point node Endpoint Average range Uniformity Conventional method 50 times 52.5 Å 50.0 Å 47.5 Å 50.0 Å 5.0Å 5% The present invention 1st thin film 25 times 26.25Å 25.0 yen 23.75Å 25.0 yen 2.5 Å 5% 2nd thin film 25 times 23.75Å 25.0 yen 26.25Å 25.0 yen 2.5 Å 5% 1st + 2nd thin film 50 times 50.0 Å 50.0 Å 50.0 Å 50.0 Å 0.0Å 0%

 As shown in Table 1, according to the conventional method, a thin film is deposited at a starting point and a thin film at an end point, and a thin film having an average of 50 mW and a range of 5 m uniformity of 5% is obtained. That is, a thin film having a non-uniform thickness of 5 Å in thickness difference between the starting point and the end point is formed.

According to the present invention, the process of introducing the source gas, the reaction gas, and the purge gas in the first direction has the same thickness distribution as the first thin film of Table 1 after 25 cycles, and then the same as that of the first thin film. In order to form a thin film of the kind, the process of introducing the source gas, the reaction gas, and the purge gas in the second direction is performed 25 cycles to have the same thickness distribution as the second thin film of Table 1. As a result, according to the present invention, during the final 50 cycles, the ideal type of deposition as shown in Table 1, which is 50 mW and uniformity 0%, appears in all parts of the substrate.

As another example for verifying the effects of the present invention, the effect of improving the pattern loading phenomenon is simulated. The pattern loading phenomenon is assumed to be 100% at the start point, 50% at the end point, and step coverage is the same at all locations.

In this case, as shown in Table 2, the pattern loading phenomenon is scattered in the substrate by 50% to 100% according to the conventional method.

Loading effect according to the conventional method and the present invention> cycle location A B C loading effect (B / A × 100) step coverage (C / B × 100) Conventional method 50 starting point 52.5 Å 52.5 Å 52.5 Å 100% 100% Endpoint 47.5 Å 23.75Å 23.75Å 50% 100% The present invention First Directional Thin Film 25 starting point 26.25Å 26.25Å 26.25Å 100% 100% Endpoint 23.75Å 11.88 Å 11.88 Å 50% 100% Second Directional Thin Film 25 starting point 23.75Å 11.88 Å 11.88 Å 50% 100% Endpoint 26.25Å 26.25Å 26.25Å 100% 100% 1st + 2nd thin film 50 starting point 50Å 38.13Å 38.13Å 76% 100% Endpoint 50Å 38.13Å 38.13Å 76% 100%

10A and 10B, the worst case of the pattern loading phenomenon according to the conventional method and the worst case of the pattern loading phenomenon according to the present invention are shown.

Referring to FIG. 10A, an insulating film 320 is formed on a semiconductor substrate 300, and a trench having a predetermined width is formed, and then a storage dielectric film 330 is formed on the trench inner sidewall and the upper surface of the insulating film. At this time, the specification of the three-dimensional capacitor, W is 0.1㎛, H is 1.9㎛, the aspect ratio (H / W) is 19.

Referring to FIG. 10B, an insulating film 410 and a storage dielectric film 420 are formed on the semiconductor substrate 300 through the same process as in FIG. 10A. The aspect ratio is 19, which is the same as the case of FIG. 10A.

According to the present invention, the pattern loading phenomenon is 76% to 100% of the entire substrate. The worst case is shown in Figure 10b. As shown, an improved thin film thickness can be obtained.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1A to 1D are thickness graphs for showing types of thicknesses of thin films formed according to a conventional method.

2 is a schematic view showing a film forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a timing diagram for explaining a film forming process in the film forming apparatus shown in FIG. 2.

4 is a schematic view showing a film forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a timing diagram for explaining a film forming process in the film forming apparatus shown in FIG. 4.

6 is a schematic view showing a film forming apparatus according to a third embodiment of the present invention.

FIG. 7 is a timing diagram for explaining a film forming process in the film forming apparatus shown in FIG. 6.

8 is a schematic view showing a film forming apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a timing diagram for explaining a film forming process in the film forming apparatus shown in FIG. 8.

10A and 10B show the worst point of the pattern loading phenomenon according to the conventional method and the present invention.

Explanation of symbols on main parts of drawing

100: process chamber 101: first gas supply unit

103: second gas supply unit 105: first direction

106: second direction

Claims (13)

Introducing a first process gas in a first direction horizontal to the substrate in a constant reaction space to form a first thin film on the substrate surface; Introducing a second process gas in a second direction horizontal to the substrate and perpendicular to the first direction to form a second thin film of the same type as the first thin film on the surface of the first thin film; Introducing a third process gas in a third direction horizontal to the substrate and opposite to the first direction to form a third thin film of the same type as the first thin film on the surface of the second thin film; And Chemical vapor deposition comprising introducing a fourth process gas in a fourth direction horizontal to the substrate and opposite to the second direction to form a fourth thin film of the same type as the first thin film on the third thin film surface; Way. delete delete The chemical vapor deposition method of claim 1, wherein the first to fourth thin films are any one of silicon, a dielectric film, a metal film, or a composite film. Adsorbing the first source gas to a surface of the substrate by introducing a first source gas in a first direction horizontal to the substrate in the chamber; Purging the non-adsorbed first source gas using the first purge gas in the first direction; Introducing a first reaction gas in the first direction to react the first source gas adsorbed on the surface of the substrate with the first reaction gas to form a first atomic layer; Purging reaction byproducts and unreacted first reaction gas using a second purge gas in the first direction; Adsorbing the second source gas to the surface of the first atomic layer by introducing a second source gas in a second direction horizontal to the substrate and perpendicular to the first direction; Purging the unadsorbed second source gas using a third purge gas in the second direction; Introducing a second reaction gas in the second direction to react the second source gas adsorbed on the first atomic layer with the second reaction gas to form a second atomic layer of the same type as the first atomic layer; step ; Purging reaction byproducts and unreacted second reaction gas using a fourth purge gas in the second direction; Adsorbing the third source gas to a surface of the second atomic layer by introducing a third source gas in a third direction horizontal to the substrate and opposite to the first direction; Purging the unadsorbed third source gas using a fifth purge gas in the third direction; Introducing a third reaction gas in the third direction to react the third source gas adsorbed on the second atomic layer with the third reaction gas to form a third atomic layer of the same type as the first atomic layer; step ; Purging reaction by-products and unreacted third reaction gas using a sixth purge gas in the third direction; Adsorbing the fourth source gas to the surface of the third atomic layer by introducing a fourth source gas in a fourth direction horizontal to the substrate and opposite to the second direction; Purging the unadsorbed fourth source gas using a seventh purge gas in the fourth direction; Introducing a fourth reaction gas in the fourth direction to react the fourth source gas adsorbed on the third atomic layer with the fourth reaction gas to form a fourth atomic layer of the same type as the first atomic layer; step ; And Purging reaction by-products and unreacted fourth reaction gas using an eighth purge gas in the fourth direction. delete delete The method of claim 5, wherein the first to fourth atomic layers are any one of silicon, a dielectric film, a metal film, or a composite film. A chamber having a reaction space for receiving a substrate; A first gas supply unit positioned at a side of the chamber and introducing a first process gas in a first direction horizontal to the substrate; A second gas supply part for introducing a second process gas in a second direction positioned in a vertical direction of the first gas supply part and horizontal to the substrate; A third gas supply part for introducing a third process gas in a third direction located in a direction opposite to the first gas supply part and horizontal to the substrate; And a fourth gas supply unit for introducing a fourth process gas in a fourth direction located in a direction opposite to the second gas supply unit and horizontal to the substrate. The chemical vapor deposition apparatus according to claim 9, further comprising first to fourth exhaust parts for discharging the first to fourth process gases. delete A chamber having a reaction space for receiving a substrate; A first gas supply unit positioned at a side of the chamber and introducing first source gas, first reaction gas, first purge gas, and second purge gas in a first direction horizontal to the substrate; A first vessel located at the same direction as the first gas supply unit at the center of the chamber and purging unadsorbed material, unreacted material, and impurities using the first purge gas and the second purge gas in the first direction. donate ; A second gas supply part for introducing a second source gas, a second reaction gas, a third purge gas, and a fourth purge gas in a second direction perpendicular to the first gas supply part and horizontal to the substrate; A second vessel located in the same direction as the second gas supply unit at the center of the chamber and purging unadsorbed material, unreacted material and impurities using the third purge gas and the fourth purge gas in the second direction; donate ; For introducing the third source gas, the third reaction gas, the fifth purge gas, and the sixth purge gas in a third direction which is located in a direction opposite to the first gas supply part and opposite to the first direction horizontal to the substrate, respectively. Third gas supply unit; A third vessel located at the same direction as the third gas supply unit at the center of the chamber and purging unadsorbed material, unreacted material, and impurities using the fifth purge gas and the sixth purge gas in the third direction; donate ; Introducing a fourth source gas, a fourth reaction gas, a seventh purge gas, and an eighth purge gas in a fourth direction located in a direction opposite to the second gas supply part and horizontal to the substrate and opposite to the second direction, respectively; A fourth gas supply unit for; And A fourth exhaust for purging unadsorbed material, unreacted material, and impurities using the seventh purge gas and the eighth purge gas in the same direction as the fourth gas supply part at the center of the chamber; An atomic layer deposition apparatus comprising a portion. delete