Plasma chamber and wafer etching method using the plasma chamber

Abstract

The present invention relates to a plasma chamber and a wafer etching method using the plasma chamber. The plasma chamber of the present invention includes: a housing having a reaction space therein for etching a wafer using plasma; a base plate provided inside the housing and on which the wafer is placed; and a pressure adjusting unit for adjusting the pressure inside the housing, wherein the pressure adjusting unit adjusts the pressure inside the housing to 50 to 500 mTorr. The wafer etching method using the plasma chamber of the present invention includes: a pressure adjusting step for adjusting the pressure inside the housing; and a source power adjusting step for adjusting the plasma source.

Description

[Technical Field]

[0001] The present invention relates to a plasma chamber and a wafer etching method using the plasma chamber, and more particularly to a plasma chamber and a wafer etching method using the plasma chamber that can improve selectivity while maintaining a high etch rate. [Background technology]

[0002] In general, it is very important to ensure uniformity in the process of manufacturing semiconductors, and the uniformity of semiconductors can be ensured or controlled during the etching process of the semiconductor manufacturing process.

[0003] The semiconductor etching process can be performed inside a plasma chamber, which generates plasma within a reaction space therein and uses the plasma to perform the semiconductor etching process.

[0004] A plasma source for generating plasma is provided at the top of the plasma chamber. Typical examples of plasma sources include a capacitively coupled plasma (CCP) source and an inductively coupled plasma (ICP) source.

[0005] A capacitively coupled plasma (CCP) source uses an electric field and generally allows etching to proceed at a slightly higher pressure than an inductively coupled plasma (ICP). Although the CCP source has a slower etching rate, it is known to have excellent selectivity and process reproducibility.

[0006] However, the capacitively coupled plasma (CCP) source has the problem of non-uniform plasma density, where the plasma density at the center of the wafer is relatively higher than that at the edge of the wafer, and also has the problem of requiring high RF power to be applied to increase the plasma density because the overall plasma density is relatively low.

[0007] Inductively coupled plasma (ICP) uses an induced magnetic field and has the advantage of a higher overall plasma density compared to capacitively coupled plasma (CCP) sources. ICP can increase the etching rate at a lower pressure than CCP sources, but the plasma density at the center of the wafer is relatively higher than that at the edge of the wafer, resulting in a high etching rate but low selectivity and poor process reproducibility.

[0008] As such, conventional plasma sources such as capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) have the problem of being unable to simultaneously increase the etching rate and selectivity, and it has been recognized that there is a trade-off between the etching rate and selectivity. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention is directed to solving the above-mentioned problems, and more particularly, to a plasma chamber and a wafer etching method using the plasma chamber that can improve selectivity while maintaining a high etch rate. [Means for solving the problem]

[0010] The plasma chamber of the present invention, which solves the above-mentioned problems, is a plasma chamber for forming plasma, and includes: a housing having a reaction space therein for etching a wafer using the plasma; a base plate provided inside the housing and on which the wafer is placed; and a pressure adjusting unit for adjusting the pressure inside the housing; wherein the pressure adjusting unit adjusts the pressure inside the housing to 50 to 500 mTorr.

[0011] In order to solve the above-mentioned problems, the plasma chamber of the present invention further includes a plasma source provided on the upper part of the housing to generate plasma inside the housing, and the source power of the plasma source may be 500 to 3000 W.

[0012] To solve the above-mentioned problems, the pressure adjusting unit of the plasma chamber of the present invention can adjust the pressure inside the housing to a pressure equal to or greater than a resonance pressure where the driving frequency of the plasma source and the collision frequency between particles inside the housing are the same.

[0013] In order to solve the above-mentioned problems, an etching gas is supplied into the housing of the plasma chamber of the present invention, and the etching gas supplied into the housing is discharged to the outside of the housing after reaction, and the time the etching gas remains inside the housing may be 1 to 4 seconds.

[0014] In order to solve the above-mentioned problems, the density of the plasma formed in the reaction space of the housing of the plasma chamber of the present invention is 1 / 3 cubic centimeter (cm -3 ) can be 2E11 to 5E11.

[0015] In order to solve the above-mentioned problems, the plasma chamber of the present invention further includes a bias RF source connected to the base plate and capable of applying a bias to the base plate, and the bias RF source may have a bias power of 500 to 5000 W.

[0016] In order to solve the above-mentioned problems, the plasma formed in the reaction space of the housing of the plasma chamber of the present invention includes ions and radicals, and the wafer can be etched by a synergy effect of the ions and the radicals.

[0017] To solve the above-mentioned problems, the present invention provides a wafer etching method using a plasma chamber, which etches a wafer using a plasma chamber including a housing having a reaction space therein for etching a wafer using plasma, a base plate provided inside the housing and on which the wafer is placed, a pressure controller for controlling the pressure inside the housing, and a plasma source provided on an upper part of the housing for forming plasma inside the housing, the method comprising: a pressure controlling step of controlling the pressure inside the housing to 50 to 500 mTorr via the pressure controller; and a source power controlling step of controlling the source power of the plasma source to 500 to 3000 W via the plasma source.

[0018] In order to solve the above-mentioned problems, in the pressure adjusting step of the wafer etching method using a plasma chamber according to the present invention, the pressure inside the housing can be adjusted through the pressure adjusting unit to a pressure equal to or greater than a resonance pressure at which a driving frequency of the plasma source and a collision frequency between particles inside the housing are formed to be the same.

[0019] In the wafer etching method using a plasma chamber according to the present invention, an etching gas is supplied into the housing, and the etching gas is discharged to the outside of the housing after reaction, and the time the etching gas remains inside the housing may be 1 to 4 seconds.

[0020] In order to solve the above-mentioned problems, in the wafer etching method using the plasma chamber of the present invention, the density of the plasma formed in the reaction space of the housing is 1 / 3 cubic centimeter (cm -3 ) can be 2E11 to 5E11.

[0021] In order to solve the above-mentioned problems, the plasma chamber of the wafer etching method using the plasma chamber of the present invention may further include a bias RF source connected to the base plate and capable of applying a bias to the base plate, and a bias power adjusting step of adjusting a bias power of the bias RF source to 500 to 5000 W via the bias RF source.

[0022] In the wafer etching method using a plasma chamber of the present invention, which solves the above-mentioned problems, the plasma formed in the reaction space of the housing contains ions and radicals, and the wafer can be etched by a synergy effect of the ions and the radicals. [Effects of the Invention]

[0023] The present invention relates to a plasma chamber and a wafer etching method using the plasma chamber. The pressure inside the chamber is set to a relatively high pressure compared to conventional chambers, so that wafers can be etched using both ions and radicals. This has the advantage of improving PR selectivity while maintaining a high etch rate.

[0024] Furthermore, the present invention has the advantage that it can obtain a high etch rate and a high PR selectivity while using lower power than conventional chambers using a plasma source and a bias RF source. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 illustrates ions and radicals etching a wafer. [Figure 2] FIG. 1 illustrates a plasma chamber according to an embodiment of the present invention. [Figure 3] 1A and 1B are diagrams illustrating a wafer etching method using a plasma chamber according to an embodiment of the present invention. [Figure 4] FIG. 2 illustrates a process area for using ions and radicals according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing the change in etching rate depending on bias power and pressure when etching a wafer using ions. [Figure 6] FIG. 10 is a diagram showing the change in etching rate depending on bias power and pressure when etching a wafer using ions and radicals according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] This specification explains the principles of the present invention and discloses embodiments so that those skilled in the art can practice the invention, while clarifying the scope of the invention. The disclosed embodiments may be embodied in various forms.

[0027] The terms "comprise" or "may comprise" as used in various embodiments of the present invention indicate the presence of the disclosed feature, operation, component, etc., and do not limit the presence of one or more additional features, operations, components, etc. Furthermore, in various embodiments of the present invention, the terms "comprise" or "have" as used in various embodiments of the present invention are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] When a component is referred to as being "connected or coupled" to another component, it should be understood that the component may be directly connected or coupled to the other component, but that there may be other components between the component and the other component. On the other hand, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that there is no other components between the component and the other component.

[0029] As used herein, terms such as "first," "second," etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another.

[0030] The present invention relates to a plasma chamber and a wafer etching method using the plasma chamber, and more particularly to a plasma chamber and a wafer etching method using the plasma chamber that can improve selectivity while maintaining a high etch rate.

[0031] 1, plasma is largely composed of electrons, ions 21, and radicals 22. In the conventional method of etching a wafer using plasma, the dominant species in the plasma etching process is either ions or radicals.

[0032] Specifically, in the conventional method of etching a wafer through plasma, metal etching mainly uses radicals, and oxide etching mainly uses ions.

[0033] In the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention, the dominant species during the plasma etching process is not formed by either ions or radicals, but by using ions 21 and radicals 22 simultaneously.

[0034] That is, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention use a process region in which ions 21 and radicals 22 act together to produce a synergy effect, rather than an ion-dominated reaction or a radical-dominated reaction during the plasma etching process.

[0035] More specifically, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention utilizes the resonance phenomenon caused by collisions between particles and the applied source frequency, and can improve selectivity while maintaining a high etch rate through the synergistic effect of ions and radicals.

[0036] The plasma chamber and wafer etching method using the plasma chamber according to embodiments of the present invention may solve and improve upon the problems associated with conventional methods using an inductively coupled plasma (ICP) source.

[0037] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention may be a synergistic resonance ICP (SRICP) that utilizes a resonance phenomenon and a synergy effect.

[0038] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can adjust the conditions of the plasma chamber to simultaneously use ions and radicals.

[0039] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can adjust the pressure inside the chamber, the source power of the plasma source, the plasma density inside the chamber, the bias power of the bias RF source, etc., and the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can simultaneously use ions and radicals by changing the above conditions in the plasma chamber.

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0041] Referring to FIG. 2, a plasma chamber 100 according to an embodiment of the present invention includes a housing 110, a base plate 111, and a pressure adjusting unit 120.

[0042] The housing 110 has an internal reaction space for etching the wafer 10 using plasma. The housing 110 may be the outer chamber wall of the plasma chamber 100 according to an embodiment of the present invention, and has an internal space. When the wafer 10 is loaded into the housing 110, the wafer 10 can be etched by the plasma generated inside the housing 110.

[0043] The base plate 111 is provided inside the housing 110 and supports the wafer 10. The base plate 111 may be provided inside the housing 110 and supports the wafer 20.

[0044] More specifically, the base plate 111 may be a wafer chuck that places the wafer 10 and supports the wafer 10, and when the wafer 10 is placed on the base plate 111, etching of the wafer 10 can proceed.

[0045] The pressure adjusting unit 120 adjusts the pressure inside the housing 110. The pressure adjusting unit 120 may be a pressure adjusting device that adjusts the pressure inside the housing 110, and the pressure adjusting unit 120 may be a device having various configurations as long as it can adjust the pressure inside the housing 110.

[0046] According to the embodiment of the present invention, the pressure adjusting unit 120 can adjust the pressure inside the housing 110 to 50 to 500 mTorr. As described above, the plasma chamber according to the embodiment of the present invention can use ions 21 and radicals 22 simultaneously.

[0047] In the plasma chamber according to the embodiment of the present invention, the pressure inside the housing 110 can be adjusted to 50 to 500 mTorr through the pressure adjusting unit 120 in order to simultaneously use the ions 21 and the radicals 22 .

[0048] In the plasma chamber according to the embodiment of the present invention, if the pressure inside the housing 110 is less than 50 mTorr, it is difficult to expect a synergy effect using the ions 21 and the radicals 22 simultaneously.

[0049] More specifically, if the pressure inside the housing 110 is less than 50 mTorr, an etching reaction dominated by ions 21 may occur. Also, when ions 21 and radicals 22 are used simultaneously, if the pressure inside the housing 110 is less than 50 mTorr, there is a risk of a decrease in the etching rate.

[0050] If the pressure inside the housing 110 is greater than 500 mTorr, the reaction between particles becomes too frequent, shortening the reaction time and decreasing the etching rate.

[0051] Therefore, in the plasma chamber according to the embodiment of the present invention, it is preferable that the pressure inside the housing 110 is adjusted to 50 to 500 mTorr through the pressure adjusting unit 120.

[0052] According to another embodiment of the present invention, the pressure inside the housing 110 can be adjusted to 100 to 150 mTorr, 200 to 500 mTorr, or 300 to 500 mTorr through the pressure adjusting unit 120.

[0053] The plasma chamber according to the embodiment of the present invention may further include a plasma source 130 disposed on the upper portion of the housing 110 to generate plasma inside the housing 110 .

[0054] The plasma source 130 can generate plasma and may include a coil 131 and an RF power generator 132. According to an embodiment of the present invention, the source power of the plasma source 130 may be adjusted to 500 to 3000W.

[0055] If the source power generated by the plasma source 130 is less than 500W, the etching rate decreases. Therefore, it is preferable that the source power generated by the plasma source 130 is greater than 500W.

[0056] As described above, the plasma chamber according to the embodiment of the present invention adjusts the pressure inside the housing 110 to 50 to 500 mTorr through the pressure adjusting unit 120, so the pressure inside the housing 110 can be higher than that of conventional plasma chambers.

[0057] If the source power generated by the plasma source 130 is greater than 3000 W, the plasma density may become excessively high due to the relatively high internal pressure of the housing 110. If the plasma density becomes excessively high, reactions between particles may become excessive, shortening the reaction time and reducing the etching rate.

[0058] Therefore, in the plasma chamber according to the embodiment of the present invention, it is preferable that the source power of the plasma source 130 is adjusted to 500 to 3000 W. Also, according to another embodiment of the present invention, the source power of the plasma source 130 can be adjusted to 500 to 1500 W.

[0059] The pressure adjusting unit 120 of the plasma chamber according to the embodiment of the present invention can adjust the pressure inside the housing 110 to a pressure equal to or greater than the resonance pressure.

[0060] Here, the resonant pressure may be a pressure at which the driving frequency of the plasma source 130 and the collision frequency between particles inside the housing 110 are equal.

[0061] For example, when the driving frequency of the plasma source 130 is 13.56 MHz, the resonant pressure at which the driving frequency of the plasma source 130 and the collision frequency between particles inside the housing 110 are equal may be 52 mTorr in the case of Ar gas, and when the driving frequency of the plasma source 130 is 27.12 MHz, the resonant pressure may be 104 mTorr in the case of Ar gas.

[0062] The pressure adjusting unit 120 according to an embodiment of the present invention can adjust the pressure inside the housing 110 to a pressure equal to or greater than a resonance pressure determined by a driving frequency of the plasma source 130.

[0063] According to an embodiment of the present invention, the collision frequency between particles inside the housing 110 can be determined by the product of the number of particles per unit volume and the rate constant for the collision reaction.

[0064] The plasma chamber according to an embodiment of the present invention may include a collision frequency analyzer for analyzing a collision frequency between particles generated inside the housing 110. The collision frequency analyzer may be used to derive a resonant pressure at which the collision frequency is equal to the driving frequency of the plasma source 130.

[0065] According to an embodiment of the present invention, the pressure adjusting unit 120 can receive data about the resonance pressure through the collision frequency analysis unit, and thereby adjust the pressure inside the housing 110 to a pressure equal to or greater than the resonance pressure.

[0066] According to an embodiment of the present invention, the density of the plasma formed in the reaction space of the housing 110 is cubic centimeters (cm -3 ) is preferably 2E11 to 5E11.

[0067] The density of the plasma formed in the reaction space of the housing 110 is cubic centimeters (cm -3 If the value is less than 2E11 per mol / L, the target etching rate cannot be obtained.

[0068] On the other hand, the density of the plasma formed in the reaction space of the housing 110 is 1 / 3 cubic centimeter (cm -3 ) is greater than 5E11, the ions 21 and radicals 22 may separate, which may adversely affect the selectivity.

[0069] That is, the plasma chamber according to the embodiment of the present invention simultaneously uses ions 21 and radicals 22 to increase the etching rate and selectivity, and the density of the plasma formed in the reaction space of the housing 110 is set to cubic centimeters (cm -3 ) is formed with 2E11 to 5E11.

[0070] According to an embodiment of the present invention, the density of the plasma formed in the reaction space of the housing 110 can be adjusted by the plasma source 130. Specifically, the plasma source 130 can form a plasma density inside the housing 110 suitable for simultaneously using ions 21 and radicals 22.

[0071] Referring to FIG. 2, the plasma chamber 100 according to an embodiment of the present invention may further include a bias RF source 140 connected to the base plate 111 and capable of applying a bias to the base plate 111.

[0072] The bias RF source 140 applies a bias to the base plate 111, thereby applying a bias to the plasma during the etching process.

[0073] According to an embodiment of the present invention, it is preferable that the bias power of the bias RF source 140 is adjusted to 500 to 5000 W. The bias power has a direct effect on the ions 21.

[0074] If the bias power of the bias RF source 140 is less than 500 W, the activity of the ions 21 is restricted and the radicals 22 become dominant, making it impossible to expect a synergy effect between the ions 21 and the radicals 22.

[0075] On the other hand, if the bias power of the bias RF source 140 is greater than 5000 W, the ions become dominantly active, and the synergy effect between the ions 21 and the radicals 22 cannot be expected.

[0076] As a result, in the plasma chamber 100 according to an embodiment of the present invention, the bias power of the bias RF source 140 must be adjusted to 500 to 5000 W in order to generate a synergy effect through the ions 21 and radicals 22.

[0077] An etching gas for etching a wafer may be supplied into the housing 110 of the plasma chamber 100 according to an embodiment of the present invention. After reaction, the etching gas supplied into the housing 110 may be discharged to the outside of the housing 110 via a pump or the like.

[0078] According to an embodiment of the present invention, the time period during which the etching gas remains inside the housing 110 may be 1 to 4 seconds. Here, the time period during which the etching gas remains inside the housing 110 may be from the time the etching gas is supplied into the housing 110 to the time the etching gas is discharged outside the housing 110.

[0079] If the etching gas remains in the housing 110 for less than 1 second, the etching gas does not flow smoothly and the reaction cannot proceed satisfactorily.

[0080] Conversely, if the etching gas remains inside the housing 110 for more than 4 seconds, polymerization of byproducts can cause random accumulation of byproducts inside the housing 110, which can have a negative impact on the process profile, etching rate, and etching rate uniformity.

[0081] Therefore, it is preferable that the etching gas remains inside the housing 110 for 1 to 4 seconds.

[0082] According to an embodiment of the present invention, the plasma formed in the reaction space of the housing 110 includes ions 21 and radicals 22, and the wafer 10 can be etched by the synergistic effect of the ions 21 and the radicals 22.

[0083] Furthermore, according to an embodiment of the present invention, the plasma formed in the reaction space of the housing 110 includes electrons, and the electron energy relaxation length (EERL) of the electrons may be smaller than the diameter of the housing.

[0084] The plasma chamber 100 according to an embodiment of the present invention can be operated in a process region of local electron kinetics. Conventional etching processes are operated in a process region of nonlocal electron kinetics, where the electron energy relaxation length (EERL) is always larger than the diameter of the process chamber.

[0085] However, the plasma chamber 100 according to an embodiment of the present invention can be operated in a process region with local electron kinetics where the electron energy relaxation length (EERL) is smaller than the diameter of the process chamber (the diameter of the housing 110).

[0086] Therefore, in the plasma chamber 100 according to the embodiment of the present invention, the plasma density at the ends of the housing 110 can be higher than that at the center of the housing 110, and the etching rate at the ends of the housing 110 can also be higher than that at the center of the housing 110.

[0087] In conventional etching processes, a problem of weak etching at the edge of the wafer (low edge yield problem) can occur, but the plasma chamber 100 according to an embodiment of the present invention can prevent this problem by forming the etching rate at the edge of the housing 110 to be higher than that at the center of the housing 110.

[0088] In addition, in the conventional etching process, in order to solve the problem of weak etching at the edge of the wafer (low edge yield problem), an independent RF power is applied or a heater, a lift device to prevent erosion of the edge ring, etc. are used.

[0089] However, the plasma chamber 100 according to an embodiment of the present invention does not require the use of a separate device because the etching rate at the edge of the housing 110 is higher than that at the center of the housing 110, which has the advantage of reducing manufacturing costs and improving yields.

[0090] The wafer etching method using the plasma chamber according to the embodiment of the present invention relates to a method of etching the wafer 10 through the plasma chamber 100 according to the embodiment of the present invention described above.

[0091] The plasma chamber 100 according to the embodiment of the present invention has been described in detail above, so a detailed description of the plasma chamber 100 according to the embodiment of the present invention will be omitted below.

[0092] Referring to FIG. 3, the wafer etching method using a plasma chamber according to the embodiment of the present invention includes a pressure adjusting step (S110) and a source power adjusting step (S120).

[0093] The pressure adjusting step (S110) is a step of adjusting the pressure inside the housing 110 to 50 to 500 mTorr through the pressure adjusting unit 120.

[0094] In the plasma chamber according to the embodiment of the present invention, if the pressure inside the housing 110 is less than 50 mTorr, it is difficult to expect a synergy effect using the ions 21 and the radicals 22 simultaneously.

[0095] More specifically, if the pressure inside the housing 110 is less than 50 mTorr, an etching reaction dominated by ions 21 may occur. Also, when ions 21 and radicals 22 are used simultaneously, if the pressure inside the housing 110 is less than 50 mTorr, there is a risk of a decrease in the etching rate.

[0096] If the pressure inside the housing 110 is greater than 500 mTorr, the reaction between particles becomes too frequent, shortening the reaction time and decreasing the etching rate.

[0097] Therefore, in the pressure adjusting step (S110), it is preferable to adjust the pressure inside the housing 110 to 50 to 500 mTorr through the pressure adjusting unit 120. Also, according to another embodiment of the present invention, in the pressure adjusting step (S110), the pressure inside the housing 110 can be adjusted to 100 to 150 mTorr, 200 to 500 mTorr, or 300 to 500 mTorr through the pressure adjusting unit 120.

[0098] The source power adjusting step (S120) is a step of adjusting the source power of the plasma source 130 to 500 to 3000 W via the plasma source 130.

[0099] If the source power generated by the plasma source 130 is less than 500W, the etching rate decreases. Therefore, it is preferable that the source power generated by the plasma source 130 is greater than 500W.

[0100] As described above, in the pressure adjusting step (S110), the pressure inside the housing 110 is adjusted to 50 to 500 mTorr through the pressure adjusting unit 120, so the pressure inside the housing 110 may be higher than that of a conventional plasma chamber.

[0101] If the source power generated by the plasma source 130 is greater than 3000 W, the plasma density may become excessively high due to the relatively high internal pressure of the housing 110. If the plasma density becomes excessively high, reactions between particles may become excessive, shortening the reaction time and reducing the etching rate.

[0102] Therefore, in the source power adjusting step (S120), it is preferable to adjust the source power of the plasma source 130 to 500 to 3000W.

[0103] In the pressure adjusting step (S110) according to the embodiment of the present invention, the pressure inside the housing 110 can be adjusted to a pressure equal to or greater than the resonance pressure through the pressure adjusting unit 120.

[0104] Here, the resonant pressure may be a pressure at which the driving frequency of the plasma source 130 and the collision frequency between particles inside the housing 110 are equal.

[0105] For example, when the driving frequency of the plasma source 130 is 13.56 MHz, the resonant pressure at which the driving frequency of the plasma source 130 and the collision frequency between particles inside the housing 110 are the same may be 52 mTorr, and when the driving frequency of the plasma source 130 is 27.12 MHz, the resonant pressure may be 104 mTorr.

[0106] In the pressure adjusting step (S110) according to an embodiment of the present invention, the pressure adjusting unit 120 can adjust the pressure inside the housing 110 to a pressure equal to or greater than the resonance pressure determined by the driving frequency of the plasma source 130.

[0107] According to an embodiment of the present invention, the collision frequency between particles inside the housing 110 can be determined by the product of the number of particles per unit volume and the rate constant for the collision reaction.

[0108] The plasma chamber according to an embodiment of the present invention may include a collision frequency analyzer for analyzing a collision frequency between particles generated inside the housing 110. The collision frequency analyzer may be used to derive a resonant pressure at which the collision frequency is equal to the driving frequency of the plasma source 130.

[0109] In the pressure adjusting step (S110) according to an embodiment of the present invention, the pressure adjusting unit 120 can receive data on the resonance pressure through the collision frequency analysis unit, and thus the pressure adjusting unit 120 can adjust the pressure inside the housing 110 to a pressure equal to or greater than the resonance pressure.

[0110] According to an embodiment of the present invention, the density of the plasma formed in the reaction space of the housing 110 is cubic centimeters (cm -3 ) is preferably 2E11 to 5E11.

[0111] The density of the plasma formed in the reaction space of the housing 110 is cubic centimeters (cm -3 If the value is less than 2E11 per mol / L, the target etching rate cannot be obtained.

[0112] Conversely, the density of the plasma formed in the reaction space of the housing 110 is cubic centimeters (cm -3 ) is greater than 5E11, the ions 21 and radicals 22 may separate, which may adversely affect the selectivity.

[0113] That is, the plasma chamber according to the embodiment of the present invention simultaneously uses ions 21 and radicals 22 to improve the etching rate and selectivity, and the density of the plasma formed in the reaction space of the housing 110 is set to cubic centimeters (cm -3 ) is formed with 2E11 to 5E11.

[0114] According to an embodiment of the present invention, the density of the plasma formed in the reaction space of the housing 110 may be adjusted in the source power adjusting step S120. In the source power adjusting step S120, the source power of the plasma source 130 is adjusted to adjust the density of the plasma formed in the reaction space of the housing 110 to 1 / 3 cubic centimeter (cm -3 ) can be formed at 2E11 to 5E11.

[0115] Referring to FIG. 3, the wafer etching method using a plasma chamber according to an embodiment of the present invention may further include a bias power adjusting step (S130) of adjusting the bias power of the bias RF source 140 to 500 to 5000 W via the bias RF source 140.

[0116] The bias RF source 140 applies a bias to the base plate 111, thereby applying a bias to the plasma during the etching process.

[0117] The bias power may have a direct effect on the ions 21. If the bias power of the bias RF source 140 is less than 500 W, the activity of the ions 21 is restricted and the radicals 22 become dominant, making it impossible to expect a synergy effect between the ions 21 and the radicals 22.

[0118] On the other hand, if the bias power of the bias RF source 140 is greater than 5000 W, the ions become dominantly active, and the synergy effect between the ions 21 and the radicals 22 cannot be expected.

[0119] Therefore, in order to generate a synergy effect through the ions 21 and the radicals 22, the bias power of the bias RF source 140 can be adjusted to 500 to 5000 W in the bias power adjusting step (S130).

[0120] An etching gas for etching a wafer may be supplied into the housing 110 of the plasma chamber 100 according to an embodiment of the present invention. After reaction, the etching gas supplied into the housing 110 may be discharged to the outside of the housing 110 via a pump or the like.

[0121] According to an embodiment of the present invention, the time period during which the etching gas remains inside the housing 110 may be 1 to 4 seconds. Here, the time period during which the etching gas remains inside the housing 110 may be from the time the etching gas is supplied into the housing 110 to the time the etching gas is discharged outside the housing 110.

[0122] If the etching gas remains in the housing 110 for less than 1 second, the etching gas does not flow smoothly and the reaction cannot proceed satisfactorily.

[0123] On the other hand, if the etching gas remains inside the housing 110 for more than 4 seconds, the byproducts may randomly accumulate inside the housing 110 due to polymerization, which may adversely affect the process.

[0124] Therefore, it is preferable that the etching gas remains inside the housing 110 for 1 to 4 seconds.

[0125] In the wafer etching method using a plasma chamber according to an embodiment of the present invention, the pressure adjusting step (S110), the source power adjusting step (S120), and the bias power adjusting step (S130) do not need to be performed in order, and each step can be performed regardless of the order.

[0126] In addition, in the wafer etching method using a plasma chamber according to an embodiment of the present invention, the pressure adjusting step (S110), the source power adjusting step (S120), and the bias power adjusting step (S130) may be performed simultaneously.

[0127] As described above, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can adjust the pressure inside the housing 110 through the pressure adjusting unit 120, adjust the source power through the plasma source 130, and adjust the bias power through the bias RF source 140.

[0128] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can improve selectivity while maintaining a high etch rate by controlling the pressure inside the housing 110, the source power, and the bias power to generate a resonant pressure effect due to the number of particle collisions and a synergy effect by simultaneously using ions 21 and radicals 22.

[0129] According to an embodiment of the present invention, the plasma formed in the reaction space of the housing 110 includes ions 21 and radicals 22, and the wafer 10 can be etched by the synergistic effect of the ions 21 and the radicals 22.

[0130] Furthermore, according to an embodiment of the present invention, the plasma formed in the reaction space of the housing 110 includes electrons, and the electron energy relaxation length (EERL) of the electrons may be smaller than the diameter of the housing.

[0131] Unlike conventional etching methods that are performed in a nonlocal electron kinetics process region where the electron energy relaxation length (EERL) is larger than the diameter of the process chamber, the plasma chamber 100 according to an embodiment of the present invention can be performed in a local electron kinetics process region where the electron energy relaxation length (EERL) is smaller than the diameter of the process chamber (the diameter of the housing 110).

[0132] Therefore, in the plasma chamber 100 according to the embodiment of the present invention, the plasma density at the ends of the housing 110 can be higher than that at the center of the housing 110, and the etching rate at the ends of the housing 110 can also be higher than that at the center of the housing 110.

[0133] The plasma chamber 100 according to an embodiment of the present invention can solve the problem of weak etching at the edge of the wafer (low edge yield problem) by forming the etching rate at the edge of the housing 110 to be higher than that at the center of the housing 110, and has the advantage of not requiring the use of a separate device to solve the problem.

[0134] Referring to FIG. 4, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention finds a process region where ions 21 and radicals 22 can be used simultaneously and proceeds with etching.

[0135] Region A in Figure 4 is a stable plasma regime where the plasma maintains its stability over time. Region B in Figure 4 is a region where excessive byproducts are generated, and region C in Figure 4 is a region where the plasma etch profile is distorted. Therefore, regions B and C in Figure 4 cannot be suitable process regions.

[0136] In Figure 4, region D is a region with a center low etch rate, and region E is a region where the process results do not change over time and are repeatable. To improve repeatability over time while avoiding wafer edge yield loss, a region that satisfies both region D and region E may be a preferred process region.

[0137] In conclusion, area F in FIG. 4, which is included in area A but does not fall under areas B and C, and simultaneously satisfies areas D and E, can be the appropriate process area.

[0138] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can adjust conditions such as pressure inside the housing 110, source power, bias power, etc. to control the wafer etching process in the F region where ions 21 and radicals 22 can be used simultaneously.

[0139] That is, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can form a process region in the F region where ions 21 and radicals 22 can be used simultaneously by adjusting the pressure inside the housing 110, the source power, and the bias power. This generates a synergy effect between the ions 21 and the radicals 22, thereby improving selectivity while maintaining a high etch rate.

[0140] As described above, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can maintain a high etch rate by simultaneously using the ions 21 and radicals 22.

[0141] Referring to Figure 5, when using only ions, as in conventional etching methods, the etching rate tends to decrease as the pressure increases. Ions are independent of temperature and perform best at low pressures. When etching using ions, the bias power must be increased to increase the etching rate. (Referring to Figure 5, the etching rate can be increased as the bias power increases.)

[0142] However, radicals increase exponentially with temperature, and as the pressure increases, the reaction becomes more active, allowing the etching rate to be increased. Therefore, if ions and radicals are used simultaneously as in the embodiment of the present invention, the etching rate can be improved by increasing the pressure without increasing the bias power.

[0143] Specifically, referring to FIG. 6, when ions and radicals are used simultaneously as in the embodiment of the present invention, as the pressure increases, the etching rate decreases up to a certain point, and once the critical point is passed, the etching rate increases as the pressure increases.

[0144] The etching rate increases as the pressure increases, and above this critical point, a synergy effect occurs between ions and radicals, improving the etching rate. In the plasma chamber and wafer etching method using the plasma chamber according to the present invention, the pressure in the housing 110 is set to be above the critical point (50 mTorr).

[0145] However, if the pressure continues to increase, the surface reaction time may become too short and the etching rate may not increase sufficiently. Therefore, in the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention, the pressure in the housing 110 is set to 50 mTorr to 500 mTorr.

[0146] In the etching rate vs. pressure graph in Figure 6, the dotted line represents the graph when the bias power is reduced from the solid line. Referring to Figure 6, if the bias power is adjusted appropriately, a high etching rate can be obtained at a pressure above the critical point.

[0147] For this purpose, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can set the bias power to 500 to 5000W and the source power to 500 to 3000W.

[0148] That is, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can form a pressure that can improve the etching rate by generating a synergy effect between ions and radicals, and can implement a process region having an optimal etching rate by adjusting the bias power and source power.

[0149] The plasma chamber according to the embodiment of the present invention may include a controller that controls the operation of the pressure regulator 120 , the plasma source 130 , the RF power generator 132 , and the bias RF source 140 .

[0150] According to an embodiment of the present invention, the pressure adjusting unit 120, the plasma source 130, the RF power generator 132, and the bias RF source 140 are controlled in operation through the control unit, thereby creating a condition in which ions 21 and radicals 22 can be used simultaneously.

[0151] In addition, the pressure adjusting step (S110), the source power adjusting step (S120), and the bias power adjusting step (S130) of the wafer etching method using a plasma chamber according to an embodiment of the present invention can be performed under control via the control unit.

[0152] The plasma chamber and wafer etching method using the plasma chamber according to the above-described embodiment of the present invention have the following advantages.

[0153] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can etch the wafer using both ions and radicals by forming the pressure inside the chamber at a relatively high pressure compared to conventional chambers, thereby providing the advantage of improving the PR selectivity while maintaining a high etch rate.

[0154] The plasma chamber and wafer etching method using the plasma chamber according to embodiments of the present invention can be performed in a pressure range (50 to 500 mTorr) where local electron kinetics are applied, and in this case, the etching rate at the edge can be higher than that at the center.

[0155] Therefore, the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention have the advantage of being able to prevent a decrease in uniformity at the edge of the wafer.

[0156] The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention are suitable for HARC (High Aspect Ratio Etch) processes, and can achieve high etching rates and high selectivity with low power in other processes as well.

[0157] Although the plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention have been described mainly for the etching process, the present invention is not limited thereto. The plasma chamber and wafer etching method using the plasma chamber according to the embodiment of the present invention can be applied to processes such as deposition, ashing, PR stripping, doping, etc. in addition to the etching process.

[0158] The plasma chamber and wafer etching method using the plasma chamber according to embodiments of the present invention can be applied to etching processes and deposition processes that require high etching rates, but are not limited thereto. Of course, they can also be applied to many processes that simultaneously require high etching rates and improved selectivity at low power.

[0159] The plasma chamber and wafer etching method using the plasma chamber according to embodiments of the present invention can be used to improve inductively coupled plasma (ICP), but is not limited to this and can also be used with various types of plasma.

[0160] Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely an example, and those skilled in the art will recognize that various modifications and variations of the embodiment are possible. Therefore, the true technical scope of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. In a plasma chamber for forming a plasma, a housing having an internal reaction space for etching wafers via plasma; a base plate provided inside the housing and on which the wafer is placed; a pressure adjusting portion for adjusting the pressure inside the housing; The plasma chamber is characterized in that the pressure adjusting unit adjusts the pressure inside the housing to 50 to 500 mTorr.

2. The plasma source is disposed on the upper portion of the housing and generates plasma inside the housing.

2. The plasma chamber of claim 1, wherein the source power of the plasma source is 500 to 3000 W.

3. The pressure adjustment unit is The driving frequency of the plasma source and the collision frequency between particles inside the housing are the same as the resonance pressure formed; 3. The plasma chamber of claim 2, wherein the pressure inside the housing is adjusted to a pressure greater than the resonance pressure.

4. An etching gas is supplied into the housing, and the etching gas supplied into the housing is discharged to the outside of the housing after reaction; 2. The plasma chamber of claim 1, wherein the etching gas remains inside the housing for 1 to 4 seconds.

5. The density of the plasma formed in the reaction space of the housing is cubic centimeter (cm －３ 2. The plasma chamber of claim 1, wherein the .lambda. / .lambda.

6. The semiconductor device further includes a bias RF source connected to the base plate and capable of applying a bias to the base plate; 2. The plasma chamber of claim 1, wherein the bias power of the bias RF source is 500 to 5000 W.

7. the plasma formed in the reaction space of the housing includes ions and radicals; 2. The plasma chamber of claim 1, wherein the wafer is etched by a synergy effect of the ions and the radicals.

8. A wafer etching method for etching a wafer through a plasma chamber including: a housing having a reaction space therein for etching the wafer through plasma; a base plate provided inside the housing and on which the wafer is placed; a pressure adjusting unit for adjusting the pressure inside the housing; and a plasma source provided on an upper portion of the housing for forming plasma inside the housing, a pressure adjusting step of adjusting the pressure inside the housing to 50 to 500 mTorr via the pressure adjusting unit; a source power adjusting step of adjusting a source power of the plasma source to 500 to 3000 W via the plasma source.

9. In the pressure adjusting step, The pressure adjusting unit adjusts the driving frequency of the plasma source to a resonance pressure where the collision frequency between particles inside the housing is equal to the resonance pressure; 9. The method of claim 8, wherein the pressure inside the housing is adjusted to a pressure greater than the resonance pressure.

10. An etching gas is supplied into the housing, and the etching gas supplied into the housing is discharged to the outside of the housing after reaction; 9. The method of claim 8, wherein the etching gas remains in the housing for 1 to 4 seconds.

11. The density of the plasma formed in the reaction space of the housing is cubic centimeter (cm －３ 9. The wafer etching method using a plasma chamber according to claim 8, wherein the concentration of the plasma is 2E11 to 5E11 per 1000 keV.

12. The plasma chamber includes a bias RF source connected to the base plate and capable of applying a bias to the base plate; 10. The method of claim 8, further comprising: adjusting a bias power of the bias RF source to 500 to 5000 W via the bias RF source.

13. the plasma formed in the reaction space of the housing includes ions and radicals; 9. The wafer etching method according to claim 8, wherein the wafer is etched by a synergy effect of the ions and the radicals.

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