A thin film deposition apparatus and a thin film deposition process method

Abstract

This invention provides a thin film deposition apparatus and a thin film deposition process. The radio frequency (RF) power supply of the thin film deposition apparatus is connected from the bottom of a heating plate, which serves as the upper electrode, and a spray plate as the lower electrode. A plasma field for carbon plug deposition is formed between the upper and lower electrodes. The RF power supply frequency is greater than 13.56 MHz to increase the diffusion free path of free radicals during carbon plug deposition. Carbon plug deposition is achieved through a one-step deposition process. The thin film deposition apparatus and process provided by this invention can increase the filling depth of carbon plugs, improve film roughness, and increase throughput even with a high aspect ratio.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing, and more particularly to a thin film deposition apparatus and a thin film deposition process. Background Technology

[0002] Fabricating a larger number of NAND memory cells on a substrate places high demands on the depth of the channels formed by directional etching. Existing 3D NAND technology fabricates a larger number of NAND memory cells through multiple stages, but this method requires a suitable etch stop layer to protect the memory cells fabricated in the previous stage from being affected by the directional etching in the next stage. Carbon plugs are considered a suitable etch stop layer, offering advantages such as high etch selectivity, high pattern fidelity, and the ability to be dry-cleaned in an oxygen atmosphere.

[0003] However, in existing technologies, carbon plugs still present some problems in actual thin film deposition processes. For example, the carbon plugs do not fill deeply enough, the filling is not uniform enough, the throughput is low, and the film surface roughness is poor, which makes subsequent mechanical polishing processes difficult.

[0004] In order to overcome the above-mentioned defects of the existing technology, there is an urgent need in the field for a thin film deposition equipment and a thin film deposition process that can increase the filling depth of carbon plugs, improve the roughness of the film and increase the production capacity when the aspect ratio is high. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a thin film deposition apparatus and a thin film deposition process method, which can increase the filling depth of carbon plugs, improve the roughness of the film and increase the production capacity when the aspect ratio is high.

[0007] Specifically, in the thin film deposition apparatus provided by the first aspect of the present invention, an RF power supply is connected from the bottom of a heating plate, the heating plate serves as the upper electrode, a spray plate serves as the lower electrode, a plasma field for carbon plug deposition is formed between the upper electrode and the lower electrode, the frequency of the RF power supply is greater than 13.56 MHz to increase the diffusion free path of free radicals during the carbon plug deposition process, and the carbon plug deposition is achieved by a one-step deposition method.

[0008] Preferably, in one embodiment of the present invention, the frequency of the radio frequency power supply is 27.12MHz or 40MHz.

[0009] Preferably, in one embodiment of the present invention, the power of the radio frequency power supply is 500 to 3000W.

[0010] Preferably, in one embodiment of the present invention, the pressure of the thin film deposition equipment is 11 to 30 torr and the temperature is 400 to 650°C.

[0011] Furthermore, the thin film deposition process method provided by the second aspect of the present invention includes the steps of: turning on the radio frequency power supply of the thin film deposition apparatus provided by the first aspect of the present invention, wherein the frequency of the radio frequency power supply is greater than 13.56MHz; and introducing process gas into the thin film deposition apparatus to perform carbon plug deposition.

[0012] Preferably, in one embodiment of the present invention, the frequency of the radio frequency power supply is 27.12MHz or 40MHz.

[0013] Preferably, in one embodiment of the present invention, the power of the radio frequency power supply is 500 to 3000W.

[0014] Preferably, in one embodiment of the present invention, the process gas includes C2H2, He, H2, N2O, N2, Ar and CO2.

[0015] Preferably, in one embodiment of the present invention, the flow rate of C2H2 is 200-1000 sccm, the flow rate of He is 200-3000 sccm, the flow rate of H2 is 40-500 sccm, the flow rate of N2O is 50-400 sccm, the flow rate of N2 is 2000-8000 sccm, the flow rate of Ar is 500-9000 sccm, and the flow rate of CO2 is 100-2000 sccm.

[0016] Preferably, in one embodiment of the present invention, the pressure of the thin film deposition equipment is 11 to 30 torr and the temperature is 400 to 650°C. Attached Figure Description

[0017] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0018] Figure 1 A schematic diagram of a thin film deposition apparatus according to some embodiments of the present invention is shown;

[0019] Figure 2 A schematic diagram of a carbon plug deposited by a thin film deposition apparatus 100 provided in some embodiments of the present invention is shown;

[0020] Figure 3 A schematic diagram of a thin film deposition apparatus is shown, in which the radio frequency power supply is connected from the spray plate.

[0021] Figure 4 A simplified schematic diagram of a thin film deposition apparatus 100 is shown;

[0022] Figure 5 A schematic diagram of a carbon plug deposited when the radio frequency power supply is connected from the spray plate is shown.

[0023] Figure 6 A schematic diagram of a carbon plug deposited using a thin film deposition apparatus with a frequency of 13.56 MHz radio frequency power supply is shown.

[0024] Figure 7 A comparison diagram of the fill depth of a thin film deposition apparatus using a 13.56 MHz radio frequency power supply and a thin film deposition apparatus 100 is shown; and

[0025] Figure 8 A comparison chart showing the production capacity of a thin film deposition apparatus using a 13.56MHz radio frequency power supply and a thin film deposition apparatus 100 is presented.

[0026] Figure label:

[0027] 100: Thin film deposition equipment;

[0028] 101: Plasma;

[0029] 110: Radio frequency power supply;

[0030] 111: Impedance matching circuit;

[0031] 112: AC filter;

[0032] 120: Heating plate;

[0033] 130: Sprayer plate;

[0034] 140: Cavity sidewall;

[0035] 210: Substrate;

[0036] 221: First material layer;

[0037] 222: Second material layer;

[0038] 231, 232: Carbon film;

[0039] 301: Plasma;

[0040] 310: Radio frequency power supply;

[0041] 320: Sprayer plate;

[0042] 330: Heating plate;

[0043] 340: Cavity sidewall;

[0044] 510: Surface carbon film;

[0045] 610: Hollow;

[0046] 710, 720: Fill depth results; and

[0047] 810, 820: Production capacity results. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood as the orientations shown in the relevant paragraphs and accompanying drawings. These relative terms are for illustrative purposes only and do not imply that the described apparatus must be manufactured or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0051] It is understood that although terms such as "first," "second," and "third" may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first components, regions, layers, and / or parts discussed below may be referred to as second components, regions, layers, and / or parts without departing from some embodiments of the present invention.

[0052] As mentioned above, existing technologies still present some problems in the actual deposition process of carbon plugs. For example, the carbon plug filling depth is not deep enough, the filling is not uniform enough, the production capacity is low, and the film surface roughness is poor, which makes subsequent mechanical polishing processes difficult.

[0053] In order to overcome the above-mentioned defects of the prior art, the present invention provides a thin film deposition apparatus and a thin film deposition process method, which can increase the filling depth of carbon plugs, improve the roughness of the film and increase the production capacity when the aspect ratio is high.

[0054] Please refer to Figure 1 , Figure 1 A schematic diagram of a thin film deposition apparatus provided according to some embodiments of the present invention is shown.

[0055] like Figure 1 As shown, the radio frequency power supply 110 of the thin film deposition equipment 100 can be connected from the bottom of the heating plate 120. An impedance matching device 111 and an AC filter 112 can be sequentially provided between the radio frequency power supply 110 and the heating plate 120.

[0056] In some embodiments, the thin film deposition apparatus 100 may be a PECVD (Plasma-Enhanced Chemical Vapor Deposition) thin film deposition apparatus.

[0057] The heating plate 120, connected to the radio frequency power supply 110, can serve as the upper electrode, and the spray plate 130 as the lower electrode. A plasma field for carbon plug deposition can be formed between the upper and lower electrodes, i.e., between the heating plate 120 and the spray plate 130. The frequency of the radio frequency power supply is greater than 13.56 MHz to increase the diffusion free path of free radicals during carbon plug deposition. Figure 1 In the embodiment shown, the frequency of the radio frequency power supply 110 can be 27.12MHz.

[0058] Please refer to Figure 2 , Figure 2 A schematic diagram of a carbon plug deposited by a thin film deposition apparatus 100 provided in some embodiments of the present invention is shown.

[0059] like Figure 2 As shown, the substrate 210 may have a structure consisting of a first material layer 221 and a second material layer 222 stacked on top of it. In some embodiments, the substrate may have a stacked ONO (Oxide-Nitride-Oxide) structure, where the first material layer 221 is an oxide layer and the second material layer 222 is a nitride layer. The stacked structure above the substrate 210 is etched to form channels with a high aspect ratio. Figure 2As shown, the thin film deposition apparatus 100 of the present invention, which uses a radio frequency power supply with a frequency of 27.12MHz, has a channel filled with a carbon film 231 and a carbon film 232 deposited on the surface of the stacked structure.

[0060] Here, compared to carbon plugs deposited by a thin film deposition apparatus where the RF power supply is connected from the spray plate, carbon plugs deposited by a thin film deposition apparatus 100 where the RF power supply 110 is connected from the bottom of the heating plate 120 can have a denser and smoother film, and the roughness of the surface carbon film 232 of the carbon plug is also effectively improved. For example... Figure 2 As shown, the carbon film 232 deposited on the surface of the carbon plug by the thin film deposition equipment 100 is very smooth.

[0061] Please refer to Figure 3 and Figure 4 , Figure 3 A schematic diagram of a thin film deposition apparatus with radio frequency power supplied from a spray plate is shown. Figure 4 A simplified schematic diagram of a thin film deposition apparatus 100 is shown.

[0062] The relationship between the sheath voltage of the electrode and the electrode area is shown below:

[0063]

[0064] Where Aa is the area of ​​electrode a, Ab is the area of ​​electrode b, Va is the sheath voltage of electrode a, and Vb is the sheath voltage of electrode b.

[0065] When the area Aa of electrode a is greater than the area Ab of electrode b, the sheath voltage Va of electrode a will be less than the sheath voltage Vb of electrode b; similarly, when the area Ab of electrode b is greater than the area Aa of electrode a, the sheath voltage Vb of electrode b will be less than the sheath voltage Va of electrode a.

[0066] like Figure 3 As shown, when the RF power supply 310 is connected to the thin film deposition equipment from the spray plate 320, the spray plate 320 serves as the upper electrode, and the heating plate 330 serves as the lower electrode, forming plasma 301 between the spray plate 320 and the heating plate 330. The area of ​​the upper electrode is the same as the area of ​​the spray plate 320, and the area of ​​the lower electrode is the sum of the areas of the heating plate 330 and the cavity sidewall 340 of the thin film deposition equipment.

[0067] like Figure 4 As shown, the radio frequency power supply 110 is connected from the bottom of the heating plate 120, which is the upper electrode, and the spray plate 130 is the lower electrode. Plasma 101 is formed between the heating plate 120 and the spray plate 130. The area of ​​the upper electrode is the same as the area of ​​the heating plate 120, and the area of ​​the lower electrode is the sum of the areas of the spray plate 130 and the cavity sidewall 140 of the thin film deposition equipment 100.

[0068] The area of ​​the spray plate is larger than the area of ​​the heating plate, meaning that... Figure 4 In the embodiment shown, when the radio frequency power supply 110 is connected from the bottom of the heating plate 120, the area of ​​the upper electrode is smaller than when the radio frequency power supply 310 is connected from the spray plate 320. The sheath voltage acting on the heating plate 120 is higher, and the ion energy provided is also higher, thus making it easier to form high-density plasma.

[0069] Furthermore, since the wafer is placed on the heating plate 120, a higher sheath voltage applied to the heating plate 120 can result in a higher sheath potential on the wafer. In addition, the RF power supply 110, after being connected to the heating plate 120, can directly apply power to the wafer. Compared to the method where the RF power supply is connected from the spray plate, the RF transmission path to the wafer is shorter, thereby improving RF utilization.

[0070] Thus, the radio frequency power supply 110, connected from the bottom of the heating plate 120, can generate higher ion energy, forming a high-density plasma, resulting in... Figure 2 The resulting film is denser. Furthermore, since the radio frequency can act directly on the wafer, the utilization rate of the radio frequency power supply 110 is improved, the probability of partial discharge is reduced, and a higher sheath potential is achieved on the wafer.

[0071] Please refer to the reference. Figure 5 , Figure 5 A schematic diagram of a carbon plug deposited when the radio frequency power supply is connected from the spray plate is shown.

[0072] like Figure 5 As shown, when the RF power supply is connected from the spray plate, i.e., when the RF power supply is connected from the top, the carbon film 510 deposited on the surface of the carbon plug is uneven and has very poor roughness. However, when the RF power supply 110 of the thin film deposition apparatus 100 is connected from the heating plate 120, the deposited... Figure 2 The carbon film 232 on the surface of the carbon plug shown is very smooth, and its roughness is relatively low compared to... Figure 5 The surface carbon film 510 shown has also been greatly improved.

[0073] As mentioned above, NAND flash memory cells have high channel aspect ratios. Low-frequency (e.g., 400kHz) radio frequency (RF) power supplies have high ion energy. Compared to high-frequency RF power supplies, low-frequency RF power supplies tend to form carbon films on the surface during the initial thin-film deposition process, blocking the channel openings. Therefore, with high channel aspect ratios, low-frequency RF power supplies are extremely unfavorable for channel filling.

[0074] Compared to a radio frequency power supply with a frequency of 13.56 MHz, the radio frequency power supply 110 provided by this invention has a higher frequency. The frequency of the radio frequency power supply 110 is greater than 13.56 MHz to increase the diffusion free path of free radicals in the plasma field during carbon plug deposition. In other embodiments, the frequency of the radio frequency power supply 110 may preferably be 40 MHz.

[0075] Higher frequency radio frequency (RF) power supplies provide higher plasma densities, which facilitates the formation of denser thin films and thus improves film roughness. Simultaneously, higher frequency RF power supplies effectively increase the diffusion path of free radicals, thereby increasing the filling depth of the carbon plugs. Thus, the thin film deposition apparatus 100 can achieve carbon plug deposition in a one-step deposition process.

[0076] Please refer to Figure 6 , Figure 6 A schematic diagram of a carbon plug deposited using a thin-film deposition apparatus with a frequency of 13.56 MHz radio frequency power supply is shown.

[0077] like Figure 6 As shown, the carbon plugs deposited by a thin-film deposition apparatus using a 13.56MHz RF power supply, when using a one-step deposition method, do not achieve sufficient filling depth and are prone to forming voids 610 at the top of the channel, resulting in an unreliable deposited film. Therefore, after deposition, the thin-film deposition apparatus using a 13.56MHz RF power supply requires an intermediate etching method to open up the blocked area on the upper surface of the channel, followed by a second deposition to achieve a higher filling depth and obtain a reliable etch stop layer without voids. In other words, the thin-film deposition apparatus using a 13.56MHz RF power supply requires a multi-step deposition process of deposition, etching, and re-deposition to form a relatively reliable film with a high aspect ratio. This multi-step deposition method is cumbersome and has low throughput.

[0078] Please continue to refer to this. Figure 2 The thin film deposition apparatus 100 can ensure sufficient channel filling depth without void formation when using one-step deposition. This demonstrates that using a high-frequency radio frequency power supply can effectively increase the diffusion path of free radicals, thereby increasing the carbon plug filling depth and preventing void formation at the channel tip.

[0079] Please refer to Figure 7 , Figure 7 A comparison diagram of the fill depth of a thin film deposition apparatus using a 13.56MHz radio frequency power supply and a thin film deposition apparatus 100 is shown.

[0080] like Figure 7As shown, a thin-film deposition apparatus using a 13.56MHz RF power supply performs carbon plug filling of the channel through a multi-step deposition process. The carbon plug filling depth is as follows. Figure 7 The filling depth results in Figure 710 show a filling depth of 375–435 nm. The thin film deposition equipment 100 achieves carbon plug filling through a one-step deposition process, and the carbon plug filling depth is as shown in Figure 710. Figure 7 As shown in the filling depth result 720, the filling depth is 435-440 nm. It can be seen that the filling depth of the thin film deposition equipment 100 using one-step deposition is deeper and more uniform than the filling depth of the thin film deposition equipment using a 13.56 MHz RF power supply using multi-step deposition.

[0081] Please refer to Figure 8 , Figure 8 A comparison chart showing the production capacity of a thin film deposition apparatus using a 13.56MHz radio frequency power supply and a thin film deposition apparatus 100 is presented.

[0082] like Figure 8 As shown, a thin-film deposition equipment using a 13.56MHz RF power supply achieves carbon plug filling through a multi-step deposition process, with a throughput of X pcs / h (pieces / hour). Thin-film deposition equipment 100 achieves carbon plug filling through a one-step deposition process, with a throughput of 1.4X pcs / h (pieces / hour). Compared to the multi-step deposition process used by the thin-film deposition equipment using a 13.56MHz RF power supply, the throughput of thin-film deposition equipment 100 is 1.4 times higher. This demonstrates that the thin-film deposition equipment using a 13.56MHz RF power supply, due to its cumbersome multi-step deposition process, significantly impacts throughput. In contrast, thin-film deposition equipment 100, with its simple one-step deposition process, achieves higher filling depth and better filling uniformity, greatly simplifying the process flow and significantly increasing throughput.

[0083] Thus, the thin film deposition equipment 100 can achieve a higher filling depth, and in the process of carbon plug filling using a one-step deposition method, it can ensure the filling depth while avoiding the formation of voids, thereby greatly improving production capacity.

[0084] In summary, the thin film deposition apparatus provided by this invention, by changing the connection method of the radio frequency (RF) power supply to the heating plate, results in a higher sheath potential and higher plasma density on the wafer, significantly improving the roughness of the carbon plug process thin film. Furthermore, the combination of the thin film deposition apparatus with a higher frequency (>13.56MHz) RF power supply increases the diffusion path of free radicals during carbon plug deposition, thereby further improving the film roughness while increasing the carbon plug filling depth.

[0085] Furthermore, based on the thin film deposition equipment provided by this invention, carbon plug deposition can be achieved through the thin film deposition process method provided by this invention. The thin film deposition process method includes step S1: turning on the radio frequency power supply of the thin film deposition equipment. The frequency of the radio frequency power supply is greater than 13.56MHz.

[0086] Because the radio frequency (RF) power supply operates at a higher frequency and generates a higher plasma density, its power can be appropriately reduced in some embodiments. Reducing the RF power supply power can decrease the probability of abnormal discharges during the process reaction. In some embodiments, the RF power supply power is 500–3000 W.

[0087] Subsequently, the thin film deposition process may include step S2: introducing process gases into the thin film deposition apparatus to perform carbon plug deposition. The process gases may include C2H2, He, H2, N2O, N2, Ar, and CO2. In some embodiments, the flow rate of C2H2 may be 200–1000 sccm, the flow rate of He may be 200–3000 sccm, the flow rate of H2 may be 40–500 sccm, the flow rate of N2O may be 50–400 sccm, the flow rate of N2 may be 2000–8000 sccm, the flow rate of Ar may be 500–9000 sccm, and the flow rate of CO2 may be 100–2000 sccm.

[0088] In a preferred embodiment, during carbon plug deposition, the pressure of the thin film deposition equipment is 11–30 torr, and the temperature is 400–650°C. Under higher pressure, combined with the thin film deposition equipment provided by this invention, high-performance deposited films can be achieved. Higher pressure easily generates more free radicals; simultaneously, the high frequency of the thin film deposition equipment provided by this invention helps increase the diffusion path of free radicals, thus further facilitating thin film deposition. Furthermore, low-pressure, high-temperature environments easily generate localized abnormal discharge phenomena; the high-pressure environment of the thin film deposition equipment helps reduce these phenomena.

[0089] In some embodiments, after carbon plug deposition, the filling depth and film surface roughness of the carbon plug deposition can be tested and the production capacity can be calculated using focused ion beam microscopy.

[0090] Compared with the prior art, the carbon plugs formed by the thin film deposition equipment and thin film deposition process provided by the present invention have greatly improved filling depth, filling uniformity and film roughness, and the production capacity has also been increased.

[0091] In summary, the thin film deposition equipment provided by this invention, combined with the thin film deposition process method provided by this invention, can increase the filling depth of carbon plugs, improve the roughness of thin films, and reduce deposition steps under conditions of high depth-to-width ratio, thereby increasing production capacity.

[0092] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0093] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thin film deposition apparatus, characterized by, The radio frequency power supply is connected from the bottom of the heating plate, which serves as the upper electrode and the spray plate as the lower electrode. A plasma field for carbon plug deposition is formed between the upper electrode and the lower electrode. The frequency of the radio frequency power supply is greater than 13.56MHz to increase the diffusion free path of free radicals during the carbon plug deposition process. The carbon plug deposition is achieved through a one-step deposition method.

2. The thin film deposition apparatus as described in claim 1, characterized in that, The frequency of the radio frequency power supply is 27.12MHz or 40MHz.

3. The thin film deposition apparatus as described in claim 1, characterized in that, The power of the radio frequency power supply is 500-3000W.

4. The thin film deposition apparatus as described in claim 1, characterized in that, The pressure of the thin film deposition equipment is 11–30 torr, and the temperature is 400–650°C.

5. A thin film deposition process, characterized in that, Including the following steps: The radio frequency power supply of the thin film deposition apparatus as described in any one of claims 1 to 4 is switched on, wherein the frequency of the radio frequency power supply is greater than 13.56 MHz; and Process gas is introduced into the thin film deposition equipment to perform carbon plug deposition.

6. The thin film deposition process method as described in claim 5, characterized in that, The frequency of the radio frequency power supply is 27.12MHz or 40MHz.

7. The thin film deposition process method as described in claim 5, characterized in that, The power of the radio frequency power supply is 500-3000W.

8. The thin film deposition process method as described in claim 5, characterized in that, The process gases include C2H2, He, H2, N2O, N2, Ar, and CO2.

9. The thin film deposition process method as described in claim 8, characterized in that, The flow rate of C2H2 is 200–1000 sccm, the flow rate of He is 200–3000 sccm, the flow rate of H2 is 40–500 sccm, the flow rate of N2O is 50–400 sccm, the flow rate of N2 is 2000–8000 sccm, the flow rate of Ar is 500–9000 sccm, and the flow rate of CO2 is 100–2000 sccm.

10. The thin film deposition process method as described in claim 5, characterized in that, The pressure of the thin film deposition equipment is 11–30 torr, and the temperature is 400–650°C.

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