KR100600051B1 - Apparatus of atomic layer deposition and method for fabrication of tertiary thin film using the same - Google Patents

Abstract

The present invention provides an atomic layer deposition apparatus and a method for forming a ternary thin film suitable for implementing a hafnium oxide film and an aluminum oxide film in a laminate structure in a chamber. The semiconductor device manufacturing method of the present invention provides a first source in one quadrant. A first nozzle for injecting gas, a second nozzle for injecting a second source gas into three quadrants, and third and fourth nozzles for injecting reactant gas into two and four quadrants; And simultaneously supporting a circular shower head having a fifth nozzle for injecting purge gas into the center thereof, a plurality of wafers corresponding to the shower head, and applying different temperatures to the wafers in the corresponding zones. And atomic layer deposition equipment having a rotatable wafer support means.

Laminate, atomic layer deposition, hafnium oxide film, aluminum oxide film, dielectric film

Description

Atomic layer deposition equipment and method for forming ternary thin film using the same {APPARATUS OF ATOMIC LAYER DEPOSITION AND METHOD FOR FABRICATION OF TERTIARY THIN FILM USING THE SAME}

1A and 1B are graphs illustrating a conceptual diagram of an ALD deposition method according to the related art and a deposition rate according to a TMA source supply time;

2 is a plan view and a sectional view of a heater unit of a chamber according to an embodiment of the present invention;

3 is a plan view of the shower head of the chamber top plate according to the embodiment of the present invention;

4 is a conceptual view of a valve for laminate deposition of an hafnium oxide film and an aluminum oxide film according to an embodiment of the present invention;

5 is a conceptual diagram of a gas line connection for each shower head according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

20: chamber 21: high temperature part

22: low temperature part 23: wafer

24: rotating plate 25: rotating shaft

26: outlet 27: shower head

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor device manufacturing technology, and more particularly, to a method of depositing a laminate dielectric film.

Generally, a hafnium oxide ('HfO ₂ ') / aluminum, aluminum oxide ('Al ₂ O ₃ ') of a dielectric material (Dielectric Matrial) constituting a memory capacitor in a DRAM (Dynamic Random Acess Memory) ) Is used as a laminate structure, that is, a structure in which a hafnium oxide film (HfO ₂ ) and an aluminum oxide film (Al ₂ O ₃ ) are repeatedly stacked in a monolayer, and the structure is atomic layer deposition (hereinafter referred to as atomic layer deposition). Deposition in one deposition chamber using the 'ALD' method.

Hafnium oxide has a dielectric leakage current due to low crystalline conversion temperature (200 ° C to 700 ° C) and low band gap (Eg to 5.5eV), despite high dielectric constant (ε-30). It is therefore vulnerable to scale down.

Thus, capacitor materials for memory in DRAMs of 0.10 technology have a relatively low dielectric constant (ε-9), but have excellent thermal stability and low permeability to impurities such as alkali ions and A laminate structure of aluminum oxide film and hafnium oxide film having excellent dielectric leakage characteristics is used.

Recently, since chemical vapor deposition (CVD) is difficult to apply to a structure having a very large aspect ratio due to the limitation of step coverage, Atomic layer deposition using surface reactions; ALD) is being applied.

1A and 1B are graphs illustrating a conceptual diagram of an ALD deposition method according to the related art and a deposition rate according to a TMA source supply time.

As shown in FIG. 1A, the ALD deposition method utilizes a self-surface reaction limited mechanism.

First, in the first step, the wafer is loaded into the chamber, and then source gas (mainly TMA in the case of aluminum oxide film) is fed into the chamber to induce chemical absorption of the source gas on the wafer surface. In the second step, purge step, a purge gas is injected (for example, an inert gas) to remove excess unadsorbed / reacted source gas or reaction adduct.

Subsequently, in the third step, a reaction gas (mainly H ₂ O or O _{3 in} the case of an aluminum oxide film) is supplied to induce a reaction with the surface groups of AlCh ₃ ^* and AlCh ₂ ^* chemisorbed on the wafer surface to deposit an atomic layer. Perform the process. Subsequently, in the fourth step, a purge gas such as an inert gas is injected again to discharge excess reaction gas and reaction adducts.

By repeating the above processes in one cycle (one cycle), an atomic layer thin film of a desired thickness is deposited.

Because ALD method uses surface reaction limiting method, it is possible to control the thickness of thin film by atomic layer and to deposit regardless of the topology of the underlying film to obtain conformal and uniform thin film. have. In addition, since the source gas and the reaction gas are separated from each other as an inert gas and supplied to the chamber, particle generation by gas phase reaction can be suppressed as compared with chemical vapor deposition (CVD). In addition, multiple collisions between the source gas and the wafer may improve the use efficiency of the source gas and reduce the period.

Subsequently, as shown in FIG. 1B, as a deposition rate according to the TMA source feeding time using the ALD method, a sufficient flux FQ (Q) capable of reacting globally to the exposed wafer surface is supplied.

At this time, it can be seen that as the supply time increases, the deposition rate increases. When the TMA source gas supply time passes 0.4 seconds, the deposition rate is saturated to have a constant value of about 0.700 Å / cycle.

That is, the deposition rate (Thickness / cycle, Å / cycle) is saturated by the flux Q _c above the threshold, wherein the cycle time is the sum of the source gas supply time, purge time, reaction gas supply time, and purge time. Say The flux of the source gas and the reactant gas is the product of flow rate and supply time, and securing Q _c through increasing the flow rate causes vortices of gas, making it difficult to secure a uniform thin film throughout the substrate. Generally, a method of increasing the supply time is used.

As described above, the ALD deposition method requires a flux of Qc or more to ensure a uniform thin film and a constant deposition rate throughout the substrate by a magnetic surface reaction limiting mechanism, and this uniform deposition rate is higher than that of the thin film deposited by the CVD method. There is a weak point that the deposition rate is three times lower. This low deposition rate is a major disadvantage of applying the ALD method to actual industrial sites.

In addition, in order to implement HfAlO with a laminate structure in a single chamber type deposition apparatus, a hafnium oxide source and an aluminum oxide source were supplied at the same temperature, a purge and a reaction gas were supplied, and a final purge was performed. Due to the difference in deposition temperature, there is a difficulty in implementing a thin film that can reduce the structure of good leakage current and structure.

The present invention has been proposed to solve the above problems of the prior art, and an object thereof is to provide an ALD device and a ternary thin film forming method suitable for implementing a hafnium oxide film and an aluminum oxide film in a laminate structure in a chamber.

ALD equipment and ternary thin film forming method of the present invention for achieving the above object is provided with a first nozzle for injecting the first source gas in the first quadrant, the second nozzle for injecting the second source gas in the third quadrant A circular shower head having a third nozzle and a fourth nozzle for injecting the reaction gas into the second and fourth quadrants, and having a fifth nozzle for injecting the purge gas into a central portion thereof; And ALD equipment for supporting a plurality of wafers corresponding to and at the same time, applying different temperatures to the wafers within the zone, and having a rotatable wafer support means.

In addition, the ALD equipment and ternary thin film forming method of the present invention for achieving the above object in the ternary thin film forming method using the ALD equipment of claim 1, wherein the area of the region corresponding to the position of the first to fourth nozzles; A first step of loading the first to fourth wafers onto the wafer support means; a second step of dividing the first and second wafers into the third and fourth wafers and heating them to different temperatures; The third step of injecting the first to the reaction gas through the four nozzles to induce adsorption on the wafer, stopping the injection of the first to the reaction gas and purging, rotating the wafer support means by one quadrant A fourth step and a fifth step of repeating the third and fourth steps.

Hereinafter, the most preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the technical idea of the present invention. .

2 is a plan view and a cross-sectional view of the heater unit of the chamber according to an embodiment of the present invention.

As shown in FIG. 2, a chamber 20 including a side wall, an upper plate and a lower plate, and a hole type that radiates gas such as source gas, oxygen source gas, purge gas, and cleaning gas through the center of the upper plate of the chamber. The shower head 27, the lower plate (not shown), the rotating shaft 25 through the center of the lower plate at the same time, a plurality of wafers 23 are seated on the wafer support 100 at the same distance from the center, the bottom center A discharge plate 26 having a baffle structure for discharging the gas introduced from the hole-type shower head 27 to the outside through the rotating plate 24 fixed to the rotating shaft 25 and the lower plate along the side wall adjacent to the rotating edge. Equipped. The upper surface of the rotating plate 24 is provided with a mounting groove (not shown) on which the wafer 23 is seated, thereby preventing the atomic layer from being deposited on the bottom surface of the wafer 23 and simultaneously rotating the rotating plate 24. 23) to prevent shaking.

Referring to the present invention with reference to such ALD equipment, first, four wafers 23 are loaded into a chamber. At this time, the wafer 23 uses one selected from bare silicon, polycrystalline, or doped silicon.

Then, the wafer 23 uses a single metal or a binary metal at this time.

Alternatively, a wafer in which an insulating film such as an oxide film or a nitride film is formed on the wafer can also be used.

Subsequently, a pre-heating step is performed in order for the temperature of the wafer support 100 to reach the reaction temperature. Preheating of the wafer support 100 proceeds for 10 seconds to 10 minutes at a temperature of 200 ℃ to 250 ℃. At this time, inert gas Ar and N ₂ gas are injected to reduce the preheating time.

When the preheating is performed to reach the reaction temperature, the high temperature portion 21 temperature of the wafer support 100 is 300 ° C to 430 ° C, and the low temperature portion 22 temperature is 200 ° C to 300 ° C.

Thus, the reason for dividing the wafer support 100 into the high temperature portion 21 and the low temperature portion 22 is that, when forming an aluminum oxide film and a hafnium oxide film in a laminate structure in a single chamber in the prior art, the temperature having the best characteristics of both materials Since it was necessary to select one of the, due to the difference in the optimum deposition temperature of the aluminum oxide film and hafnium oxide film has a difficulty in implementing the HfAlO thin film.

Therefore, in order to secure the best material properties of the aluminum oxide film and the hafnium oxide film, the wafer support 100 is divided into a high temperature portion 21 and a low temperature portion 22.

3 is a plan view of the shower head of the chamber top plate according to an embodiment of the present invention.

As shown in FIG. 3, first, gas is injected into the reactor, the first nozzle 31 for injecting TEMAH in one quadrant A, and the third quadrant C for injecting TMA. The second nozzle 33 is provided, and the third and fourth nozzles 32 and 34 for injecting the reaction gas into the second quadrant B and the fourth quadrant D are provided, and a purge gas is provided at the center of the quadrant. Reference is made to a circular shower head with a fifth nozzle 35 for injection.

In the fifth nozzle 35 in the center of the shower head, an inert gas of Ar or N ₂ is released to keep TMA and TDMAH flowing out of the chamber uniformly, and emit purge gas during the purge process.

Proceeding gas injection through the shower head, Al (CH ₃ ) ₃ and TDMAH are physically adsorbed on the wafer, with physical adsorption proceeding via von der walls force.

Subsequently, when the lower film on the wafer is an aluminum oxide film, the injected TDMAH is adsorbed and reacted on the wafer to form Al-O-Hf [N (Ch ₃ )] ₃ ^* surface species, and when the lower film is a hafnium oxide film, the injected TMA Adsorbs onto the wafer and reacts with the underlying film to form Hf-O-Al (CH ₃ ) ₂ ^* surface species. At this time, the amount (Flux) of Al (CH ₃ ) ₃ and TDMAH injected into the chamber is 10 ⁹ to 10 ⁵ Lagmular. Where 1 Lagmular is 10 ^-6 Torr ^* sec.

The time t0-t1 injected into a chamber is 10 msec-10 sec, and the pressure inside a chamber is 10 mTorr-10 Torr. In order to maintain the pressure in the chamber, an inert gas, N ₂ or Ar, is injected simultaneously into the reactor.

Subsequently, the flow of gas in the chamber is continuous, and pumping is carried out at a constant power so that the introduction of new sources is continued.

Subsequently, the source O ₃ of the reaction gas is supplied through the second and fourth nozzles 32 and 34 formed in the second quadrant B and the fourth quadrant D of the shower head.

4 is a conceptual view illustrating a valve for laminate deposition of a hafnium oxide film and an aluminum oxide film according to an embodiment of the present invention.

Referring to FIG. 4, a conceptual diagram of a hafnium oxide film and an aluminum oxide film is deposited. An oxygen valve, an oxygen source gas Al and an Hf valve are in an on state, and a purge gas N ₂ and an Ar valve are turned off in a period t0 to t1. (OFF) state.

This is a nozzle for injecting the aluminum oxide source located in the third quadrant 33, the hafnium oxide source located in the first quadrant 31, and the sources of the reactive gas located in the second and fourth quadrants B and D in the interval t0 to t1. At the same time gas is injected.

Subsequently, when the injection of gas is stopped, the oxygen valve and the oxygen source valve are in an OFF state, and the purge gas valve is in an ON state in the period of t1 to t2. The purge gas is injected through the nozzles of the first to fourth quadrants A to D, and the wafer support 100 is rotated 90 degrees while the purge is performed.

When the purge is finished, the wafer support 100 is rotated 90 ° again. After the wafer support 100 is rotated 180 °, the deposition of a thin film of the laminate of the aluminum oxide film and the hafnium oxide film is completed. After the wafer support 100 is rotated 360 °, one layer of the aluminum oxide film and one layer of the hafnium oxide film is rotated. Is deposited.

Therefore, repeating the step of injecting and purging the source gas with one cycle, the steps t0 to t2 are repeated until the desired thickness is obtained, and the thickness per cycle uses the concept of limiting the surface reaction of atomic layer deposition. The desired thickness is obtained by repeatedly dividing the thickness per cycle.

5 is a conceptual diagram illustrating a gas line connection of a shower head for each time according to an embodiment of the present invention.

As shown in FIG. 5, in the t0 to t1 section, TMA and the hafnium oxide film, which are the source gases of the aluminum oxide film, are formed through the first nozzle 51 and the third nozzle 53 of the first quadrant A and the third quadrant C. Oxygen source gas H ₂ O or O ₃ is injected through the second nozzle 52 and the fourth nozzle 54 of TDMAH, the second quadrant B and the fourth quadrant D, which are the source gas of Injection proceeds clockwise about the third quadrant (C). The main purge continues through the fifth nozzle 55 during the source gas injection.

Subsequently, in the t1 to t2 section, source gas injection is stopped, and purge gases N ₂ and Ar are injected through the nozzles 51 to 54 formed in the 1 to 4 quadrants A to D of the shower head to purge. The purge gas is injected through the fifth nozzle 55 to proceed with the main purge.

According to the above embodiment, a batch-type traveling wave ALD deposition apparatus capable of simultaneously depositing microwaves in one chamber can overcome the low throughput of ALD.

The present invention can be used in the deposition of diffusion barrier metal such as TiSiN, and can also be used in the deposition of high dielectric constant (high k, insulation constant) HfAlSi _x which is a gate insulating material of a semiconductor device.

In another aspect, the present invention can be used for depositing a single thin film of HfO ₂ and Al ₂ O ₃ using only one of the TMA or TDMAH than the area that is sent to the source of the shower head in the laminated structure of HfO ₂ and Al ₂ O _3.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

The present invention described above may improve the characteristics of the device by implementing a dielectric material with a high throughput in a laminate structure that cannot be implemented by atomic layer deposition.

Claims (14)

A first nozzle for injecting the first source gas into one quadrant; a second nozzle for injecting the second source gas into three quadrants; a third for injecting the reaction gas into the second and fourth quadrants; A circular shower head having a fourth nozzle, and having a fifth nozzle for injecting purge gas into a central portion thereof; A wafer support means capable of simultaneously supporting a plurality of wafers corresponding to the shower head, applying different temperatures to respective wafers in the corresponding zones, and rotating the wafers Atomic layer deposition equipment having a. In the method of forming a ternary thin film using the ALD equipment of claim 1, A first step of loading first to fourth wafers onto the wafer support means in a region corresponding to the positions of the first to fourth nozzles; A second step of dividing the first and second wafers into the third and fourth wafers and heating them to different temperatures; A third step of inducing adsorption onto a corresponding wafer by injecting first to reaction gases through the first to fourth nozzles; A fourth step of stopping injection of the first to reaction gases and performing purging, rotating the wafer support means by one quadrant; And A fifth step of repeating the third and fourth steps Ternary thin film forming method comprising a. The method of claim 1, And the wafer support means rotates clockwise about the third quadrant. The method of claim 2, The third and fourth wafer is a ternary thin film forming method having a temperature of 300 ℃ to 430 ℃. The method of claim 2, The first source gas injected through the first nozzle is a ternary thin film formation method using TDMAH. The method of claim 2, The second source gas is injected through the second nozzle is a ternary thin film forming method using a TMA. The method of claim 2, Reaction gas injected through the third and fourth nozzle is a ternary thin film formation method using H ₂ O or O ₃ . The method of claim 2, The purge is a ternary thin film formation method that proceeds using N ₂ or Ar purge gas. The method of claim 2, And the second source gas has an amount of 10 ⁹ to 10 ⁵ lagmular. The method of claim 2, The second step of dividing the first and second wafers and the third and fourth wafers and heating them to different temperatures, A ternary thin film forming method comprising preheating and main heating. The method of claim 10, The pre-heating is a ternary thin film forming method that is carried out for 10 seconds to 10 minutes at a temperature of 200 ℃ to 250 ℃. The method of claim 10, The pre-heating method of forming a ternary thin film injecting Ar or N ₂ gas to reduce the heating time. The method of claim 2, The first to fourth wafers are ternary thin film forming method using silicon selected from bare silicon, polycrystalline silicon, doped silicon. The method of claim 2, The first to fourth wafer is a ternary thin film forming method using a metal selected from a single metal or binary metal.

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