Apparatus and method for controlling etch selectivity and damage in EUV PR / sion pattern using grid pulsing technique

Abstract

An embodiment of the present invention increases the etching resistance of a photoresist in an EUV PR / SiON pattern using an ion beam etching apparatus to which grid pulsing is applied, so that the photoresist is etched less and SiON is etched more, thereby improving the etching selectivity. According to an embodiment of the present invention, it is possible to improve the LER through repetition of constant etching and deposition, thereby reducing process defects and enabling damage control.

Description

Device and method for controlling etch selectivity and damage in EUV PR / SION patterns using grid pulsing technology

[0001] The present invention relates to an apparatus and method for controlling etching selectivity and damage in an EUV PR / SiON pattern using grid pulsing technology, and more particularly, to an apparatus and method for controlling damage through improved etching selectivity and improved surface roughness compared to a conventional ion beam etching process through pulsing a grid and a substrate that extract ions from plasma.

[0002] As devices become more miniaturized and line widths decrease, the importance of lithography technology is increasing. Lithography, a circuit pattern formation technology, is the process technology that plays the most significant role in device miniaturization.

[0003] The minimum line width that can be realized has been reduced by improving the resolution with an extreme ultraviolet (EUV) light source with a wavelength of 13.5 nm compared to when using a conventional ArF light source with a wavelength of 193 nm.

[0004] When etching SiON patterned with conventional EUV photoresist, the low sensitivity of EUV photoresist necessitates a low thickness, potentially leading to pattern collapse. This thin thickness leads to reduced etch resistance and etch selectivity during the etching process.

[0005] The etching process also affects line-edge roughness (LER). Because EUV light sources emit 1 / 14th as many photons as ArF light sources, fewer light sources are needed to form the pattern. This resulting shot noise can cause discontinuous activation of photoacid generators (PAGs) within the photoresist, potentially leading to an increase in LER.

[0006] Thin thickness and LER can cause problems in subsequent processes after pattern transfer, such as metal wiring resistance and low gate controllability.

[0007] Accordingly, in the case of fine patterning using EUV technology, a technology requiring high etch selectivity is required due to low level of process defects (LER) and thin thickness.

[0008] The technical problem to be achieved by the present invention is to provide a device and method that can control a high etching selectivity due to a low level of process defects (LER) and a thin thickness in fine patterning using EUV technology.

[0009] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0010] In order to achieve the above technical task, one embodiment of the present invention comprises: a source chamber containing plasma; a plurality of grids arranged in a vertical direction parallel to each other, the grids including a plurality of through holes through which an ion beam passes from the plasma in the source chamber; and a substrate portion in which the ion beam reaching the lower portion of the plurality of grids through the through holes reacts with an etching gas to perform an etching process; the substrate portion comprises: a substrate; a SiON layer located on an upper surface of the substrate; And a polymer deposition layer and an etching photoresist layer positioned on one side and the other side opposite to each other on the upper surface of the SiON layer; and the plurality of grids include a first grid, a second grid, and a third grid in order of proximity in the direction in which the ion beam passes, and a positive DC voltage is applied to the first grid, a negative DC voltage is applied to the second grid, and the third grid is grounded, and the first grid and the second grid are designed to apply a pulse, thereby providing an EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology.

[0011] In an embodiment of the present invention, it may be characterized in that in the pulse application state, ions with high energy cause etching, and in the pulse stop state, ions with low energy cause deposition.

[0012] In an embodiment of the present invention, it may be characterized in that the selectivity is improved and the line edge roughness is improved by repeating the pulse application and the pulse stop.

[0013]

[0014] In order to achieve the above technical problem, another embodiment of the present invention provides a method for controlling etching selectivity and damage in an EUV PR / SiON pattern using a grid pulsing technique, including: a step of generating an ion beam from plasma in a source chamber; a step of allowing the ion beam to pass through a through hole of each of a first grid, a second grid, and a third grid; a step of injecting a gas into a lower portion of the third grid; and a step of applying a pulse (Pulse-on) to the first grid and the second grid so that ions having high energy in the ion beam react with the gas to etch a substrate portion, and so that ions having low energy in the ion beam react with the gas to deposit on the substrate portion when the pulse is stopped (Pulse-off).

[0015] In an embodiment of the present invention, it may be characterized in that the selectivity is improved and the line edge roughness is improved by repeating the pulse application (Pulse-on) and the pulse stop (Pulse-off).

[0016] In an embodiment of the present invention, the etching selectivity may be improved by increasing the etching resistance of the photoresist so that less of the photoresist is etched and more of SiON is etched.

[0017] In an embodiment of the present invention, the gas may be characterized as being a gas of the fluorocarbon (CxFy) series.

[0018] According to an embodiment of the present invention, in an EUV PR / SiON pattern using an ion beam etching device applying grid pulsing, the etching resistance of the photoresist can be increased so that less photoresist is etched and more SiON is etched, thereby improving the etching selectivity.

[0019] LER improvement is possible through repeated etching and deposition, which reduces process defects and enables damage control.

[0020] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0021] Figure 1 is a schematic diagram showing an EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology according to the present invention.

[0022] Figure 2 is a schematic diagram showing the etching and deposition process of each ion in (a) the pulse on state and (b) the pulse off state.

[0023] Figure 3 is a graph showing (a) etching speed and (b) LER according to duty ratio.

[0024] Figure 4 is a top-view SEM image of the sample after etching according to the duty ratio.

[0025] Figure 5 is a side view SEM image of the sample after etching according to the duty ratio.

[0026] Figure 6 shows XPS analysis of (a) EUV PR and (b) SiON according to duty ratio.

[0027] Figure 7 shows the results of ion energy measurement according to the duty ratio.

[0028] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0029] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0030] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0032]

[0033] Figure 1 is a schematic diagram showing an EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology according to the present invention.

[0034] Referring to FIG. 1, an EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology according to an embodiment of the present invention is described.

[0035] An EUV PR / SiON pattern etching selectivity and damage control device using a grid pulsing technique according to one embodiment of the present invention may include: a source chamber containing plasma; a plurality of grids arranged vertically and parallel to each other, the grids including a plurality of through holes through which an ion beam passes from the plasma in the source chamber; and a substrate portion in which an etching process is performed by reacting the ion beam reaching the lower portion of the plurality of grids through the through holes with an etching gas.

[0036] The chamber may be divided into two parts, and the upper layer of the chamber (upper chamber) may be a chamber where plasma is discharged, and the lower layer of the chamber (lower chamber) may include a process chamber where etching actually takes place. The process chamber may be viewed as a chamber where a process is performed using ions and radicals, such as ions descending from the upper chamber.

[0037] A plurality of grids may be positioned between the upper chamber and the lower chamber. The grids may be perforated graphite or a conductive material.

[0038] Normally, gas must be injected into the upper chamber, i.e., the chamber where plasma is discharged. However, the device according to the present invention can inject gas into the lower chamber instead of the upper chamber. In addition, the gas injected into the upper and lower chambers is designed differently so that the gas is injected into the lower part of the grid, thereby reducing direct decomposition and preventing excessive polymer production. If gas is injected into the upper chamber, the problem of the gas remaining in the chamber or contaminating the grid as it descends can be prevented. The gas may be a fluorocarbon (CxFy) series gas.

[0039] The above substrate portion may include a substrate; a SiON layer positioned on an upper surface of the substrate; and a polymer deposition layer and an etching photoresist layer positioned on one side and the other side of the upper surface of the SiON layer, which are opposite to each other.

[0040] The above plurality of grids may include a first grid, a second grid, and a third grid in order of proximity in the direction in which the ion beam passes, and a positive DC voltage is applied to the first grid, a negative DC voltage is applied to the second grid, and the third grid is grounded, and the first grid and the second grid may be designed to apply a pulse.

[0041] In the pulse application state, high-energy ions cause etching, and in the pulse stop state, low-energy ions can be deposited. By repeating the pulse application and pulse stop, the selectivity can be improved and the line edge roughness can be improved.

[0042]

[0043] Figure 2 is a schematic diagram showing the etching and deposition process of each ion in (a) the pulse on state and (b) the pulse off state.

[0044] Referring to FIG. 2, an etching selectivity and damage control method in an EUV PR / SiON pattern using grid pulsing technology according to another embodiment of the present invention will be described.

[0045] A method for controlling etching selectivity and damage in an EUV PR / SiON pattern using a grid pulsing technique according to one embodiment of the present invention may include the steps of: generating an ion beam from plasma in a source chamber; passing the ion beam through each of a through hole of a first grid, a second grid, and a third grid; injecting a gas into a lower portion of the third grid; and applying a pulse (Pulse-on) to the first grid and the second grid so that ions having high energy in the ion beam react with the gas to etch a substrate portion, and stopping the pulse (Pulse-off) so that ions having low energy in the ion beam react with the gas to deposit on the substrate portion.

[0046] By repeating the pulse application (Pulse-on) and pulse stopping (Pulse-off), the selectivity and line edge roughness can be improved.

[0047] This increases the etching resistance of the photoresist, so that less photoresist is etched and more SiON is etched, thereby improving the etching selectivity.

[0048] In addition, as described above, gas generally has to be injected into the upper chamber, that is, the chamber where plasma is discharged, but the device according to the present invention can inject gas into the lower chamber instead of the upper chamber. In addition, by designing the gas injected into the upper and lower chambers differently, the gas can be injected into the lower part of the grid, thereby reducing direct decomposition and preventing excessive production of polymers. If the gas is injected into the upper chamber, contamination of the grid may occur as the gas stays in the chamber or descends, but such problems can be prevented. The gas may be a fluorocarbon (CxFy) series gas. The gas may be a fluorocarbon (CxFy) series gas.

[0049]

[0050] Hereinafter, an experimental example of the present invention will be described.

[0051]

[0052] Figure 3 is a graph showing (a) etching speed and (b) LER according to duty ratio. A duty ratio of 100 is continuous, and as the duty ratio decreases, the pulse on time decreases and the pulse off time increases.

[0053] Referring to Fig. 3, (a) the etching speeds of SiON and EUV PR increased as the duty ratio increased, and the etching selectivity tended to increase as the duty ratio decreased. Until the duty ratio is 50%, SiON is etched, while EUV PR undergoes deposition, and through this, the selectivity can be seen to be almost infinite. When the duty ratio drops below 50%, deposition occurs frequently and SiON is not etched, but only deposited, making it impossible to obtain the etching selectivity.

[0054] (b) For LER, as the duty ratio increased, the LER also tended to increase. At a duty ratio of 50%, we can confirm that the LER increases only slightly, by approximately 0.4 nanometers, from 5.8 nm to 6.2 nm. This ensures high etch selectivity and reference-level LER.

[0055]

[0056] Figure 4 is a top-view SEM image of the sample after etching according to the duty ratio.

[0057] Referring to Figure 4, it was confirmed that LER did not improve in the case of a duty ratio of 100 (continuous) in the top image, and it was confirmed that LER improved as the duty ratio decreased.

[0058]

[0059] Figure 5 is a side view SEM image of the sample after etching according to the duty ratio.

[0060] Referring to Figure 5, it can be confirmed that as the duty ratio in the side image decreases, more of the mask height survives.

[0061]

[0062] Figure 6 shows XPS analysis of (a) EUV PR and (b) SiON according to duty ratio.

[0063] Referring to Fig. 6, in the surface composition analysis measured by XPS, (a) in the case of EUV PR, the proportion of carbon represented by polymer was high at low duty ratios, and (b) in the case of SiON, as the duty ratio decreased, the proportion of carbon increased and the proportion of Si, O, and N, which are the compositions of SiON, decreased. Through this, it is judged that the deposition phenomenon by low-energy ions is strengthened at low duty ratios.

[0064]

[0065] Figure 7 shows the results of ion energy measurement according to the duty ratio.

[0066] Referring to Fig. 7, the results of measuring ion energy according to the duty ratio showed that ions with low energy in the range of approximately ~10 eV were observed at all duty ratios except for the duty ratio of 100% (continuous). In the pulse off section, deposition occurred due to the injection of fluorocarbon series gas from below due to the low ion energy, and in the high energy pulse on state, etching occurred by high energy ions. Based on this, it can be confirmed that by using grid pulsing, etching and deposition are repeated due to low energy ions and high energy ions, and based on this, the etch selectivity and LER are improved.

[0067]

[0068] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0069] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A source chamber containing plasma; A plurality of grids arranged in a vertically parallel manner, each grid comprising a plurality of through holes for passing an ion beam from the plasma within the source chamber; and A substrate portion in which the ion beam and the etching gas that pass through the through hole and reach the lower portion of the plurality of grids react to perform an etching process; The substrate portion includes a substrate; a SiON layer located on the upper surface of the substrate; and a polymer deposition layer and an etching photoresist layer located on one side and the other side of the upper surface of the SiON layer, which are opposite to each other; The above plurality of grids include a first grid, a second grid, and a third grid in order of proximity in the direction in which the ion beam passes, An EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology, characterized in that a positive DC voltage is applied to the first grid, a negative DC voltage is applied to the second grid, and the third grid is grounded, and the first grid and the second grid are designed to apply pulses.

2. In paragraph 1, An EUV PR / SiON pattern etching selectivity and damage control device using grid pulsing technology, characterized in that in the pulse application state, ions with high energy cause etching, and in the pulse stop state, ions with low energy cause deposition.

3. In paragraph 2, An etching selectivity and damage control device in an EUV PR / SiON pattern using grid pulsing technology, characterized in that the selectivity is improved and the line edge roughness is improved by repeating the pulse application and the pulse stop.

4. A step of generating an ion beam from plasma in a source chamber; A step in which the ion beam passes through the penetration holes of each of the first grid, the second grid, and the third grid; A step of injecting gas into the lower part of the third grid; and A method for controlling etching selectivity and damage in an EUV PR / SiON pattern using a grid pulsing technique, comprising: a step of applying a pulse (Pulse-on) to the first grid and the second grid, wherein ions having high energy in the ion beam react with the gas to etch the substrate portion, and when the pulse is stopped (Pulse-off), ions having low energy in the ion beam react with the gas to deposit the ions on the substrate portion; 5. In paragraph 4, A method for controlling etching selectivity and damage in an EUV PR / SiON pattern using grid pulsing technology, characterized in that the selectivity is improved and line edge roughness is improved by repeating the pulse application (Pulse-on) and pulse stopping (Pulse-off).

6. In paragraph 5, A method for controlling etching selectivity and damage in an EUV PR / SiON pattern using grid pulsing technology, characterized in that the etching selectivity is improved by increasing the etching resistance of the photoresist so that less photoresist is etched and more SiON is etched.

7. In paragraph 4, A method for controlling etching selectivity and damage in an EUV PR / SiON pattern using grid pulsing technology, characterized in that the above gas is a fluorocarbon (CxFy) series gas.

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