KR20220093499A - Dry cleaning method of a semiconductor and display chemical vapor deposition chamber using F3NO gas - Google Patents

Abstract

Disclosed is a method of dry cleaning a semiconductor and a display chemical vapor deposition chamber to which a silicon byproduct adheres. The cleaning method according to one embodiment comprises the following steps of: converting at least one cleaning gas containing F_3NO into plasma in a remote plasma generator located outside a chemical vapor deposition chamber; setting the chemical vapor deposition chamber to a predetermined process condition; and supplying active species of the cleaning gas generated in the remote plasma generator to the chemical vapor deposition chamber set to the predetermined process condition to remove a silicon byproduct from the chemical vapor deposition chamber, wherein in the predetermined process condition, internal pressure of the chemical vapor deposition chamber is set within a range of 2.0 to 4.0 Torr. In the cleaning method, the cleaning gas is activated by the remote plasma generator to clean the silicon byproduct at a high rate.

Description

Dry cleaning method of a semiconductor and display chemical vapor deposition chamber using F3NO gas

The present invention relates to a method for cleaning a chemical vapor deposition (CVD) chamber during a semiconductor and display manufacturing process. In particular, fluorine in a remote plasma source (RPS) using a cleaning gas containing F3NO (F) A silicon by-product (for example, silicon (Si), silicon oxide (SiOx) that is attached to the inside of the CVD chamber by fluorine active species or radicals by generating an active gas containing the component and supplying it to the inside of the CVD chamber , silicon nitride (SixNy, etc.)) is chemically removed.

In general, in order to manufacture a semiconductor device on a substrate, a series of processes such as deposition, etching, polishing, and cleaning are performed. These processes are performed in a deposition apparatus (eg, a CVD apparatus) or an etching apparatus having a chamber. Among them, the deposition process is a process of applying a predetermined deposition material on a substrate or a material film on the substrate in the chamber of the deposition apparatus, and the etching process selectively removes a portion of the thin film formed on the substrate formed by the deposition process or the like This is a process of forming an ultra-fine structure of a desired shape.

In general, as a result of the deposition process, in addition to the substrate, the deposition material is attached to the inner wall of the chamber, components installed inside the chamber, piping, etc., and as a result of the etching process, etching byproducts are also attached to the inner wall of the chamber. Since these deposits can cause impurities attached to the substrate in the subsequent deposition process or etching process, thereby causing defects in the semiconductor device, it is necessary to remove process by-products by frequently cleaning the processing chamber, such as the deposition chamber or the etching chamber. there is

In the cleaning process, especially in the dry cleaning process, the gaseous cleaning gas reacts with the attached substances to be removed, such as silicon by-products such as silicon (Si), silicon oxide (SiOx), silicon nitride (SixNy), and forms a highly volatile reaction dispersion. By discharging it to the outside through an exhaust pump, the deposits are removed. As a method to further increase the reactivity between the cleaning gas and the cleaning target, a plasma cleaning method using plasma is used, and the plasma increases the reactivity by making the cleaning gas into highly reactive active species or radicals. In addition, a remote plasma cleaning technology is employed in a cleaning process using plasma. The remote plasma cleaning technology is a technology that can quickly remove byproducts without damaging components in the process chamber because the plasma generator is separated from the process chamber to indirectly generate high-density plasma.

In addition to the cleaning method, the basic condition required for the cleaning gas is that the cleaning speed is fast. As such a cleaning gas, perfluoro compound gases such as CF4, C2F6, SF6, and NF3 have been conventionally used. However, the conventional perfluoro compound cleaning gas is difficult to treat the waste gas discharged after the cleaning process, and accordingly, it is expensive to lower it to an acceptable standard before discharge to the atmosphere. In addition, the conventional perfluoro compound cleaning gas is a stable compound with a long lifespan in the atmosphere, and since it has a very high global warming potential, it is pointed out as a major factor in global warming.

Accordingly, there is a need for an alternative cleaning gas having a low global warming potential and excellent cleaning performance for silicon by-products, and as one of them, F 3 NO described in Patent Document 1 is known.

Registered Patent Publication 10-2010466

The present invention is to solve the problems of the prior art, and provides a method for cleaning silicon by-products at a high rate by activating a cleaning gas containing F 3 NO, which is environmentally friendly, with a relatively low global warming potential, by a remote plasma source. aim to do

One embodiment of the present invention for solving the above problems is a method for dry cleaning a semiconductor and display chemical vapor deposition chamber to which silicon by-products are attached, F3NO in a remote plasma generator located outside the chemical vapor deposition chamber Plasmaizing at least one cleaning gas comprising: setting the chemical vapor deposition chamber to a predetermined process condition; and converting active species of the cleaning gas generated in the remote plasma generator to the predetermined process condition. and removing the silicon by-product from the chemical vapor deposition chamber by supplying it to a vapor deposition chamber, wherein the predetermined process condition sets the internal pressure of the chemical vapor deposition chamber within a range of 2.0 to 4.0 Torr. do.

According to an aspect of the embodiment, the internal pressure of the chemical vapor deposition chamber may be set within a range of 2.0 to 3.0 Torr. In this case, the internal pressure of the chemical vapor deposition chamber may be set to 2.0 Torr when silicon or silicon nitride is removed, and 3.0 Torr when silicon oxide is removed. In addition, the predetermined process condition may further include setting the temperature of the wall surface of the chemical vapor deposition chamber to 100° C. or less. In addition, the cleaning gas may include an inert gas, and a flow rate ratio of the F 3 NO introduced into the plasma generator may be 20 to 50% with respect to the flow rate of the inert gas.

According to the present invention, silicon by-products can be rapidly removed by adjusting the process conditions under which remote plasma is provided, particularly the pressure in the chemical vapor deposition chamber, while using the environmentally friendly cleaning gas containing F 3 NO.

1 is a diagram schematically showing the configuration of a cleaning apparatus of a chemical vapor deposition chamber for performing a cleaning method according to an embodiment of the present invention.
2 is a flowchart illustrating a cleaning method of a chemical vapor deposition chamber using a remote plasma according to an embodiment of the present invention.
3 is a graph showing the etching rate for each thin film of the silicon by-product according to the internal temperature of the chemical vapor deposition chamber.
4 is a graph showing the etch rate according to the flow ratio of Ar and F 3 NO.
5 is a graph illustrating an etch rate according to a process pressure of a chemical vapor deposition chamber.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and duplicate descriptions thereof are omitted.

1 is a diagram schematically showing the configuration of a cleaning apparatus for a semiconductor and display chemical vapor deposition chamber for performing a cleaning method according to an embodiment of the present invention. Referring to FIG. 1 , a cleaning apparatus 100 includes a process chamber 130 such as a remote plasma generator 110 , an equipment gas path 120 , a chemical vapor deposition chamber, and the like.

The cleaning apparatus 100 supplies active species of the cleaning gas generated by the remote plasma generator 110 to the process chamber 130 to remove various impurities attached to the process chamber 130 . For example, the cleaning apparatus 100 may be an apparatus for removing silicon byproducts such as silicon (Si), silicon oxide (SiOx), silicon nitride (SixNy), etc. attached to the chamber wall of the process chamber 130 .

The remote plasma generator 110 is a device for converting the cleaning gas supplied through a predetermined supply pipe (Gas Inlet) into a plasma, and for plasmaizing the cleaning gas through plasma discharge (P). To this end, a control gas is supplied to the plasma generator 110 together with a cleaning gas containing at least F 3 NO, and the plasma P may be generated by applying a voltage under an appropriate flow rate and pressure condition. There is no particular limitation on the type of the remote plasma generator 110, but it is preferable that the cleaning gas is dissociated by almost 100% to form a plasma P that does not contain FNO or NO.

The cleaning gas may include a combination of F3NO and O2 and/or an inert gas, wherein the inert gas may optionally use at least one inert gas from the group consisting of N2, He, Ne, Ar, Kr, Xe, Rn. have.

The remote plasma generator 110 functions as a remote plasma source (RPS) of the process chamber 130 to be cleaned. As shown in FIG. 1 , the plasma generator 110 is disposed outside (upper side) of the process chamber 130 , and one plasma generator may be provided. However, the present invention is not limited thereto, and a plurality of plasma generators 110 may be provided. In this case, the same cleaning gas and power are supplied to each plasma generator 110 to generate the same plasma or different cleaning gases and/or supplying power to generate different plasmas.

When the remote plasma generator 110 generates the plasma P, active components such as ions and electrons are generated from the cleaning gas in addition to the radicals R. In addition, an activated component of the generated cleaning gas is supplied to the process chamber 130 through the equipment gas path 120 . In this case, the cleaning apparatus 100 may be configured such that components unnecessary for the cleaning process are not sent to the process chamber 130 and are removed through the exhaust gas path 122 of the equipment gas path 120 . In addition, a cooling kit 121 is installed in the equipment gas path 120 to prevent problems such as failure due to recombination of the active gas or high heat. Although the long-term gas path 120 is illustrated as being connected to the upper side of the process chamber 130 in FIG. 1 , this is exemplary and may be connected through a side surface of the process chamber 130 or the like.

The process chamber 130 is a cleaning target of the cleaning apparatus 100 , and is for performing a unit process for manufacturing a semiconductor device, for example, a deposition process or an etching process. The process chamber 130 has an internal space limited by a chamber wall, and various parts for performing the process are installed therein and/or connected to the outside through a pipe or the like. The stage 132 for supporting a substrate in a deposition process or an etching process for manufacturing a semiconductor device is an example of a component installed in the process chamber 130 . In this specification, the 'process chamber 130' is only used on the chamber wall. It is not limited, and includes all parts that are installed inside or connected to the chamber wall, such as the stage 132 , and that require periodic cleaning together with the chamber wall.

Although not shown in the drawings, the process chamber 130 is provided with a temperature control means for controlling the temperature inside the chamber. The temperature control means includes a heater for heating the process chamber 130 and a heat exchanger for maintaining the temperature of the wall surface of the process chamber 130 at a constant temperature (eg, 100° C. or less). In addition, a pressure regulating valve and a vacuum pump for regulating the pressure inside the chamber are installed in a pipe connected to the chamber wall of the process chamber 130 .

As a result of the deposition process or the etching process in the process chamber 130 , a byproduct of the process is attached to components installed therein, including the chamber wall of the process chamber 130 . For example, the process chamber 130 is a deposition chamber for depositing a silicon compound thin film (eg, Si, SiOx, SixNy) by a chemical vapor deposition (CVD) method or silicon formed on a substrate In the case of an etching chamber for etching a compound thin film, silicon-based process by-products may be adhered to the chamber walls and components.

2 is a flowchart illustrating a method of cleaning a process chamber using a remote plasma according to an embodiment of the present invention.

1 and 2 , in the cleaning method of the process chamber according to the present embodiment, first, an inert gas (eg, argon (Ar)) for plasma ignition of the remote plasma generator 110 of the cleaning apparatus 100 . is supplied up to a pressure at which plasma can be ignited through a mass flow controller (MFC) (S10). And when the flow and pressure of the inert gas are stabilized to the set values, power is supplied to the remote plasma system for discharging the inert gas to form plasma (S20). At this time, the stabilization time of the inert gas such as Ar is important for purifying the contamination by the electronegative gas that may interfere with the ignition inside the remote plasma generator, so sufficient time must be allowed. In addition, the inert gas not only activates the ionization of the cleaning gas in the plasma, but also the active species of the inert gas weakens the bonding of silicon by-products in the chamber, thereby lowering the activation energy of the reaction of the cleaning gas with the active species. , the cleaning rate by the active species can also be improved. In the case of a conventional perfluoro cleaning gas such as CF4 or NF3, O2 is sometimes mixed together to increase the cleaning rate by increasing the concentration of F active species, but in the cleaning method of the present invention, F3NO is used as the main cleaning gas. , it is possible to sufficiently increase the cleaning rate without separately mixing O2. As will be described later with reference to FIGS. 3 to 5 , in the cleaning method according to the embodiment of the present invention, by appropriately setting the flow rate ratio of F 3 NO and Ar in the cleaning gas introduced into the plasma generator 110 , the silicon by-product is cleaned speed can be maximized.

After plasma ignition of the inert gas, the system must transition smoothly to the cleaning process. To this end, a cleaning gas containing F 3 NO is introduced into the remote plasma generator 110 (S30). However, if a large amount of gas is introduced at once when a cleaning gas such as F3NO is introduced into the remote plasma generator 110, the generated plasma may be extinguished. Therefore, in order to prevent such a problem, in this step, it is preferable that each step lasts for several seconds in the plasma forming state of the inert gas and the injection amount of the cleaning gas is increased stepwise to a target value.

In the embodiment of the present invention, since a plasma containing FNO or almost no NO is formed in the remote plasma generator 110 by including F3NO as a cleaning gas, in the remote plasma generator 110, F, F2, N, N2, O , Ar and other active gases are generated.

In addition, the active gases generated by the remote plasma generator 110 are supplied to the process chamber 130 through the equipment gas path 120 (S40). In this case, the active gas escaping from the remote plasma generator 110 may cause problems such as chemical recombination or failure due to high heat in the process of transferring a significant amount of heat and chemical energy through the equipment gas path 120 . Therefore, it is important to cool the equipment gas path 120 with the cooling kit 121 . In addition, active species and/or ions unnecessary for cleaning may be removed from the plasma through the exhaust gas path 122 .

The process chamber 130 to which the active gas is supplied is set to a predetermined process condition. As will be described later with reference to FIGS. 3 to 5 , in the cleaning method according to an embodiment of the present invention, by controlling the temperature if necessary together with the internal pressure of the process chamber 130 to which the active gas is supplied, the silicon It is possible to maximize the cleaning speed of by-products. The temperature of the process chamber 130 may be controlled by, for example, adjusting the height of the stage 132 in which the heater is installed.

When the active gas is supplied to the process chamber 130 , the active species reacts with an adherent (eg, silicon by-product) attached to the process chamber 130 , and the silicon by-product is removed from the process chamber 130 by etching ( S50 ). ). According to the cleaning method of the embodiment of the present invention, silicon (Si), silicon nitride (SixNy), and silicon oxide (SiOx) can be rapidly etched and removed from the process chamber 130 in this order.

Hereinafter, with reference to FIGS. 3 to 5 , the remote plasma generator 110 , together with the temperature and pressure in the process chamber 130 into which the active gas of the cleaning gas including F NO generated in the remote plasma generator 130 is introduced. The cleaning rate (etch rate) of the silicon-based thin film according to the flow ratio of F3NO and Ar injected into the

3 shows that the cleaning gas is supplied into the remote plasma generator 110 at a flow ratio of Ar:F3NO of 2000:500 (sccm) in the cleaning gas supply step ( S30 ), and the silicon deposits are removed in the process chamber ( S50 ). When the process pressure of 130 is set to 2.7 Torr, the internal temperature of the process chamber 130 is set through the heater temperature of the stage 132, and the silicon attachment attached to the chamber wall is replaced with a silicon-based thin film. It is a graph showing the etch rate. Referring to FIG. 3 , as the heater temperature of the stage 132 increases, the etch rate also increases almost linearly, which means that as the temperature rises, the reactive species supplied into the process chamber 130 as well as the reactivity of the Ar gas decreases. This is thought to be due to an increase in

4 is a graph showing the etching rate according to the flow rate ratio of Ar and F NO supplied into the remote plasma generator 110 in the supply step of the cleaning gas ( S30 ). The process pressure of the process chamber 130 is set to 2.7 Torr, It is a case where the heater temperature of the stage 132 is set to 100 degreeC. Here, the reason for setting the heater temperature of the stage 132 to 100°C is that the wall surface of the process chamber 130 is for vacuum, whereas the CVD deposition process is usually performed at 300-400°C to secure the characteristics of the thin film. This is because it is common to keep the temperature below 100°C to prevent deformation of the O-ring and the like. Referring to FIG. 4, first, if the flow ratio of Ar:F3NO is 2000:500 (sccm) and 1000:500 (sccm), the amount of Ar is not significantly different between the silicon-based thin films (Si, SiO2, Si3N4). It can be seen that the etching rate of the silicon thin film, the silicon nitride film, and the silicon oxide film is high in the order of the silicon thin film, the silicon nitride film, and the silicon oxide film according to the difference in chemical bonding energy. It can be seen that the silicon oxide film has a greater effect than the silicon nitride film. And when the flow ratio of Ar:F3NO is 1000:500 (sccm) and 2000:1000 (sccm), it can be seen that the greater the amount of F3NO gas or Ar gas, the greater the etching rate. It is determined that this is because there is a predetermined proportional relationship with the amount of gas.

5 shows that the cleaning gas is supplied into the remote plasma generator 110 at a flow ratio of Ar:F3NO of 2000:500 (sccm) in the cleaning gas supply step ( S30 ), and the silicon by-product removal step ( S50 ) of the process chamber It is a graph showing the etching rate for each silicon-based thin film according to the process pressure of the process chamber 130 when the heater temperature of the stage 132 of 130 is set to 100°C.

Referring to FIG. 5 , it can be seen that the etch rate gradually decreases as the process pressure increases from 2.0 Torr to 4.0 Torr. The reason why the etch rate decreases as the pressure increases is that reaction by-products generated in the etch process are not exhausted but are scattered and redeposited to cause a decrease in the etch rate. On the other hand, if the process pressure is too low, the reaction with the active species inside the process chamber 130 may be inhibited, so it is preferable to set an appropriate process pressure for each thin film.

Combining the above experimental data, if the flow ratio of Ar: F 3 NO is fixed (eg, 2000: 500 (sccm)) and the temperature of the process chamber 130 is fixed (eg, 100° C.), the cleaning process When the process pressure of the process chamber 130 is set in an appropriate range (eg, 2.0 to 3.5 Torr), the silicon-based thin film is removed at a relatively high etch rate, so the silicon by-products attached to the process chamber 130 are removed. It can be seen that they can be removed quickly. In particular, when the process pressure is in the range of 2.7 to 3.3 Torr, the cleaning effect of silicon by-products is better, and in the case of a silicon thin film and silicon nitride film, the process pressure is 2 Torr, and in the case of a silicon oxide film, the cleaning is maximized at 3.0 Torr. can do.

The above description is merely an example, and should not be construed as limiting the technical spirit of the present invention thereby. The technical idea of the present invention should be specified only by the invention described in the claims to be described later, and all technical ideas within an equivalent range should be interpreted as being included in the scope of the present invention. Therefore, it is apparent to those skilled in the art that the above-described embodiment can be modified and implemented in various forms.

100: cleaning device
110: remote plasma generator
120: long-term gas path
121: cooling kit
122: exhaust gas path
130: process chamber
132: stage

Claims (5)

A method for dry cleaning a semiconductor and display chemical vapor deposition chamber to which silicon by-products are attached, comprising:
plasmaizing at least one cleaning gas comprising F 3 NO in a remote plasma generator located outside the chemical vapor deposition chamber;
setting the chemical vapor deposition chamber to predetermined process conditions; and
supplying the active species of the cleaning gas generated by the remote plasma generator to the chemical vapor deposition chamber set under the predetermined process conditions to remove the silicon by-product from the chemical vapor deposition chamber,
The predetermined process condition includes setting an internal pressure of the chemical vapor deposition chamber within a range of 2.0 to 4.0 Torr. According to claim 1,
The cleaning method of a chemical vapor deposition chamber, characterized in that the internal pressure of the chemical vapor deposition chamber is set within a range of 2.0 to 3.0 Torr. 3. The method of claim 2,
The chemical vapor deposition chamber, characterized in that the internal pressure of the chemical vapor deposition chamber is set to 2.0 Torr when silicon or silicon nitride is removed, and 3.0 Torr when silicon oxide is removed. cleaning method. 4. The method of claim 3,
The predetermined process condition, the cleaning method of the chemical vapor deposition chamber, characterized in that it further comprises setting the temperature of the wall surface of the chemical vapor deposition chamber to 100 ℃ or less. 5. The method of claim 3 or 4,
The cleaning gas includes an inert gas, and a flow rate ratio of the F 3 NO introduced into the plasma generator is 20 to 50% with respect to the flow rate of the inert gas.

Images