Patent Application
20250232974
One or more embodiments relate to a method of filling a gap, and more particularly, to a method of filling a gap to prevent a gap structure from being damaged in a flowable gap fill process and to fill the gap without a void or a seam.
In manufacturing a semiconductor device, a gap fill process to fill the gap with an insulating layer (e.g., SiO2, SiN, TiO2 etc.) is performed in various unit processes (e.g., isolation process, patterning process and VNAND gate process etc.). When the gap is filled incompletely with the insulating layer, a void or a seam remains in the gap and a device performance becomes low accordingly due to an electrical short or a leak, for instance. Therefore, it is required for the gap to be filled with the insulating layer without a void or a seam.
In order to solve this problem, a flowable gap fill method was introduced. Filling the gap with a flowable insulating layer is an effective void-free or seamless gap fill method as the flowability of the layer enables to fill the gap more effectively from the bottom of the gap without a void or a seam.
In a gap fill process to fill the gap with TiO2 layer, the solid TiO2 layer formed on the surface of the gap may become flowable by exposing the solid TiO2 layer to a fluorine source activated by a power (e.g., NF3 plasma). However, the fluorine may damage a gap structure (e.g., SOH (spin-on-hardmask) layer). Therefore, a protective layer may be formed on the surface of the gap, followed by forming the TiO2 layer thereon.
A protective layer, a HfO2 layer, for instance, may be formed on the surface of the gap before forming the TiO2 layer. However, a delamination may occur between TiO2 layer and HfO2 layer in the subsequent process such as annealing process due to different properties (e.g., different thermal expansion coefficients), resulting in incomplete filling of the gap (e.g., seam or void).
Therefore, it is required to introduce a method of filling a gap in which the gap structure may be protected from the fluorine.
The present disclosure discloses a method of forming a protective layer to prevent the gap structure from being damaged by a fluorine in a flowable TiO2 gap fill process and to fill the gap without a void or a seam, and a method of preventing an delamination between the protective layer and the TiO2 layer formed thereon to fill the gap.
In some embodiments, a method of filling a gap provided to a substrate may comprise: providing the substrate in a reactor, and performing a flowable gap-fill cycle repeatedly. The flowable gap-fill cycle may comprise forming a first solid layer on the surface of the gap, turning the first solid layer into a flowable layer by supplying a fluorine flow amount of a fluorine source activated by a power to the first solid layer, and converting the flowable layer into a second solid layer.
The method of filling a gap may further comprise calculating a ratio of the fluorine flow amount to a thickness of the first solid layer and controlling the fluorine flow amount based on the calculated ratio.
In some embodiments, the fluorine flow amount may be equal to a flow rate of the fluorine source multiplied by a fluorine source supply time, wherein controlling the fluorine flow amount comprises controlling at least one of the flow rate of the fluorine source and the fluorine source supply time.
In some embodiments, calculating the ratio of fluorine flow amount to the thickness of the first solid layer may comprise multiplying the flow rate (sccm) of the fluorine source by the fluorine supply time (second) divided by the thickness (nm) of the first solid layer.
In some embodiments, the ratio of fluorine flow amount to the thickness of the first solid layer may be 1,000:1 sccm-second/nm or below.
In some embodiments, the flowable gap-fill cycle may be repeated until the gap is filled with the second solid layer.
In some embodiments, the gap may comprise an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, and the first solid layer may be formed on the upper surface, the lower surface, and the side surface.
In some embodiments, a portion of the first solid layer formed on the upper surface and the side surface may be fluorinated into the flowable layer. The flowable layer on the upper surface and the side surface may flow into the lower surface.
In some embodiments, the first solid layer may comprise the same material as the second solid layer.
In some embodiments, the first solid layer may comprise a titanium oxide.
In some embodiments, the first solid layer may be formed by repeating a cycle comprising: supplying a titanium source, followed by supplying an oxygen source, wherein the oxygen source may be activated by a power.
In some embodiments, the titanium source may comprise at least one of titanium tetrakis(isopropoxide) (Ti(O-iPr)4), titanium halide, cyclopentadienyl titanium, titanium bis(isopropoxide)bis(2,2,6,6-tetramethyl-3,5-heptanedionate) (Ti(O-iPr)2(thd)2), tetrakisdimethylaminotitanium (Ti[N(CH3)2]4, TDMAT), tetrakis(diethylamino)titanium ((Et2N)4Ti, TEMAT), or mixtures thereof.
In some embodiments, the oxygen source may comprise at least one of O2, O3, H2O, H2O2, NO, N2O, NO2, CO, CO2, or mixtures thereof.
In some embodiments, the flowable layer may comprise TiOxFy.
In some embodiments, the second solid layer may comprise a titanium oxide.
In some embodiments, the fluorine source may comprise at least one of F2, SF6, CF4, C2F6, CHF3, CH2F2, ClF3, NF3, C3F8, C4F8, HF, SiF4, or mixtures thereof.
In some embodiments, converting the flowable layer may be performed by a plasma treatment.
In some embodiments, the plasma treatment may be performed by supplying an oxygen source comprising at least one of O2, O3, H2O, H2O2, NO, N2O, NO2, CO, CO2, or mixtures thereof, wherein the oxygen source may be activated by a power.
In some embodiments, a method of filling a gap may comprise: providing a substrate in a reactor, wherein the substrate comprises the gap, forming a first solid layer on the surface of the gap, turning the first solid layer into a first flowable layer by supplying a fluorine source activated by a power to a the first solid layer, converting the first flowable layer into a second solid layer, forming a third solid layer on the second solid layer, turning the third solid layer into a second flowable layer by supplying the fluorine source activated by the power to the third solid layer, and converting the second flowable layer into a fourth solid layer. The first solid layer may be thicker than the third solid layer.
In some embodiments, a thickness of the first solid layer may be about 5 nm or more.
In some embodiments, a thickness of the third solid layer may be about 3 nm or less.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
Hereinafter, one or more embodiments will be described more fully with reference to the accompanying drawings.
In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Rather, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey the scope of the disclosure to one of ordinary skill in the art.
The terminology used herein is for describing particular embodiments and is not intended to limit the disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes”, “comprises” and/or “including”, “comprising” used herein specify the presence of stated features, integers, steps, processes, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, processes, members, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms first, second, etc. may be used herein to describe various members, components, regions, layers, and/or sections, these members, components, regions, layers, and/or sections should not be limited by these terms. These terms do not denote any order, quantity, or importance, but rather are only used to distinguish one component, region, layer, and/or section from another component, region, layer, and/or section. Thus, a first member, component, region, layer, or section discussed below could be termed a second member, component, region, layer, or section without departing from the teachings of embodiments.
In the specification, “gas” may include evaporated solids and/or liquids and may include a single gas or a mixture of gases. In the specification, a process gas introduced into a reaction chamber through a shower head may include a precursor gas and an additive gas.
The precursor gas and the additive gas may typically be introduced as a mixed gas or may be separately introduced into a reaction space. The precursor gas may be introduced together with a carrier gas such as an inert gas. The additive gas may include a dilution gas such as a reactive gas and an inert gas. The reactive gas and the dilution gas may be mixedly or separately introduced into the reaction space.
The precursor may include two or more precursors, and the reactive gas may include two or more reactive gases. The precursor may be a gas that is chemisorbed onto a substrate and typically contains metalloid or metal elements constituting a main structure of a matrix of a dielectric film, and the reactive gas for deposition may be a gas that is reactive with the precursor chemisorbed onto the substrate when excited to fix an atomic layer or a monolayer on the substrate. The term “chemisorption” may refer to chemical saturation adsorption.
A gas other than the process gas, that is, a gas introduced without passing through the shower head, may be used to seal the reaction space, and it may include a seal gas such as an inert gas.
In some embodiments, the term “film” may refer to a layer that extends continuously in a direction perpendicular to a thickness direction without substantially having pinholes to cover an entire target or a relevant surface or may refer to a layer that simply covers a target or a relevant surface. In some embodiments, the term “layer” may refer to a structure, or a synonym of a film, or a non-film structure having any thickness formed on a surface.
The film or layer may include a discrete single film or layer or multiple films or layers having some characteristics, and the boundary between adjacent films or layers may be clear or unclear and may be set based on physical, chemical, and/or some other characteristics, formation processes or sequences, and/or functions or purposes of the adjacent films or layers.
In the specification, the expression “containing an Si—N bond” may be referred to as characterized by an Si—N bond or Si—N bonds having a main skeleton substantially constituted by the Si—N bond or Si—N bonds and/or having a substituent substantially constituted by the Si—N bond or Si—N bonds. A silicon nitride layer may be a dielectric layer containing a Si—N bond, and may include a silicon nitride layer (SiN) and a silicon oxynitride layer (SiON).
In the specification, the expression “same material” should be interpreted as meaning that main components (constituents) are the same. For example, when a first layer and a second layer are both silicon nitride layers and are formed of the same material, the first layer may be selected from the group consisting of Si2N, SiN, Si3N4, and Si2N3 and the second layer may also be selected from the above group, but a particular film quality thereof may be different from that of the first layer.
In addition, in the specification, according as an operable range may be determined based on a regular job, any two variables may constitute an operable range of the variable and any indicated range may include or exclude terminated sites. Additionally, the values of any indicated variables may refer to exact values or approximate values (regardless of whether they are indicated as “about”), may include equivalents, and may refer to an average value, a median value, a representative value, a majority value, or the like.
In the specification where conditions and/or structures are not specified, one of ordinary skill in the art may easily provide these conditions and/or structures as a matter of customary experiment in the light of the specification. In all described embodiments, any component used in an embodiment may be replaced with any equivalent component thereof, including those explicitly, necessarily, or essentially described herein, for intended purposes, and in addition, the disclosure may be similarly applied to devices and methods.
Hereinafter, embodiments of the disclosure will be described with reference to the accompanying drawings. In the drawings, variations from the illustrated shapes may be expected because of, for example, manufacturing techniques and/or tolerances. Thus, the embodiments of the disclosure should not be construed as being limited to the particular shapes of regions illustrated herein but may include deviations in shapes that result, for example, from manufacturing processes.
Referring to
In detail, the step S20 may comprise forming a first solid layer on the surface of the gap in step S21, turning the first solid layer into a flowable layer in step S22, converting the flowable layer into a second solid layer in step S23.
After converting into the second solid layer, it is determined whether the gap is filled with the second solid layer or not in step S24. When the gap is filled with the second solid layer, performing a flowable gap-fill cycle may end, and then the substrate may be unloaded from the reactor in step S30.
However, when the gap is not filled with the second solid layer, the step S21 to the step S23 may be repeated a plurality of times. Accordingly, the flowable gap-fill cycle may be repeated a plurality of times until the gap is filled with the second solid layer. The second solid layer herein may be referred to as all solid layers formed in the subsequent cycles after forming the first solid layer in the first cycle.
The method of filling a gap according to an embodiment may comprise calculating a ratio of a fluorine flow amount to a thickness of the first solid layer and controlling an amount of the fluorine flow amount based on the calculated ratio. Accordingly, the first solid layer formed on the gap may be thick enough to protect the gap structure from a fluorine. The gap structure may comprise hereinafter not only the surface of the gap but also the layer under the surface of the gap.
In some embodiments of the present disclosure, the first solid layer may be formed as the same material as the second solid layer. Therefore, a delamination due to different material properties (e.g., a thermal expansion coefficient) may be prevented between the first solid layer and the second solid layer in the subsequent processes (e.g., an annealing process).
Since the first solid layer and the second solid layer may be the same material, a protective layer process and a gap fill process may be performed in the same reactor in-situ. Therefore, the gap fill process may be simplified and the substrate processing time may be shorter, resulting in high throughput per unit time.
The fluorine flow amount may be equal to a flow rate (sccm) of the fluorine source multiplied by a fluorine source supply time (second). Accordingly, calculating the ratio of fluorine flow amount to the thickness of the first solid layer may comprise multiplying the flow rate of the fluorine source (sccm) by the fluorine source supply time (second) divided by the thickness (nm) of the first solid layer.
In some embodiments, the ratio of the fluorine flow amount to the thickness of the first solid layer may be 1,000:1 sccm·second/nm or below, such that the gap structure may not be damaged due to the sufficient thickness of the first solid layer.
On the contrary, when the ratio of the fluorine flow amount to the thickness of the first solid layer is greater than 1,000:1 sccm·second/nm, a fluorine flow amount may be excessive such that the first solid layer may not be thick enough to protect the gap structure from the fluorine, resulting in a damage to the gap structure.
Referring to
The topography forming the upper surface 113 and the side surface 112 of the gap structure 110 may be a separate structure formed on a base substrate 115 having the lower surface 111 or may be integrated with the base substrate 115. The side surface 112 may extend generally perpendicular or at an angle with respect to the lower surface 111.
Referring to
In step S21, a first solid layer 120 may be formed on the upper surface 113, the lower surface 111 and the side surface 112 of the gap structure 110. In some embodiments, the first solid layer 120 may be formed to have a substantially uniform thickness along the surface of the gap. The first solid layer 120 may be formed by a Plasma Enhanced ALD (PEALD) method.
In some embodiments, the first solid layer 120 may comprise a titanium oxide. For example, the titanium oxide layer may be formed on the surface of the gap structure 110 by repeating a cycle comprising: supplying a titanium source, followed by supplying an oxygen source activated by a power.
In some embodiments, the titanium source may comprise at least one of titanium tetrakis(isopropoxide) (Ti(O-iPr)4), titanium halide (TiCl4), cyclopentadienyl titanium, titanium bis(isopropoxide)bis(2,2,6,6-tetramethyl-3,5-heptanedionate) (Ti(O-iPr)2(thd)2), tetrakisdimethylaminotitanium (Ti[N(CH3)2]4, TDMAT), tetrakis(diethylamino)titanium ((Et2N)4Ti, TEMAT), or mixtures thereof.
In some embodiments, the oxygen source may comprise at least one of O2, O3, H2O, H2O2, NO, N2O, NO2, CO, CO2, or mixtures thereof.
In step S22, a portion of the first solid layer 120 may turn into a first flowable layer 130 by supplying a fluorine flow amount of a fluorine source activated by a power (i.e., fluorine plasma) to the first solid layer 120. In more detail, a portion of the first solid layer 120 formed on the upper surface 113 and the side surface 112 may be fluorinated by the fluorine source activated by a power and may flow into the lower surface 111, resulting in filling the gap with a flowable layer 130.
A portion of the first solid layer 120 may react with a fluorine and become flowable. The flowable layer may flow into the lower surface 111 along the side surface 112, resulting in filling the gap with the first flowable layer 130. A remaining portion 121 of the first solid layer 120 in step S22 may have the thickness b thinner than the thickness a of the first solid layer 120 in step S21. The first solid layer 120 may comprise a titanium oxide and the first flowable layer 130 may comprise TiOxFy.
In some embodiments, the fluorine source may comprise at least one of F2, SF6, CF4, C2F6, CHF3, CH2F2, ClF3, NF3, C3F8, C4F8, HF, SiF4, or mixtures thereof.
In step S23, the first flowable layer 130 may be converted into a second solid layer 122 by plasma treatment. In this case, the second solid layer 122 may comprise the same material as the first solid layer 120. For instance, the first solid layer 121 may comprise a titanium oxide, and the second solid layer 122 may also comprise a titanium oxide. The remaining portion 121 of the first solid layer 120 in step S22 may maintain the thickness b in step S23.
In some embodiments, the plasma treatment may be performed by supplying an oxygen source comprising at least one of O2, O3, H2O, H2O2, NO, N2O, NO2, CO, CO2, or mixtures thereof, wherein the oxygen source may be activated by a power.
Referring to
In step S21′, a third solid layer 123 may be formed on the remaining portion 121 of the first solid layer 120 and the second solid layer 122. The third solid layer 123 may be formed to have a substantially uniform thickness c along the surface of the remaining portion 121 of the first layer 120 and the second solid layer 122. The third solid layer 123 may be formed by Plasma Enhanced ALD (PEALD) method.
In some embodiments, the thickness a of the first solid layer 120 in
In other words, the first solid layer 120 may be formed thick enough to protect the gap structure from a fluorine in step S22′ of the second cycle even after the thickness a of the first layer 120 is reduced to the thickness b of the remaining portion 121 in steps S22.
In some embodiments, the third solid layer 123 may comprise a titanium oxide by performing a cycle comprising: supplying a titanium source, followed by supplying an oxygen source activated by a power.
In operation S22′, the third solid layer 123 may turn into a second flowable layer 131 by supplying a fluorine flow amount of a fluorine source activated by a power (i.e., fluorine plasma) to the third solid layer 123, and may flow into the lower surface 111 of the gap structure 110 (i.e., an upper surface of the second solid layer 122), resulting in filling the remaining space of the gap with the second flowable layer 131.
In more detail, a portion of the third solid layer 123 formed on the remaining portion 121 of the first solid layer 120 may be fluorinated by reacting with a fluorine source activated by a power and become the flowable layer 131, resulting in flowing into the upper surface of the second solid layer 122 to fill the gap.
A remaining portion 124 of the third solid layer 123 may have the thickness d thinner than the thickness c of the third solid layer 123 formed in step S21′. The third solid layer 123 may comprise a titanium oxide, and the flowable layer 131 may comprise TiOxFy.
In step S23′, the flowable layer 131 may be converted into a fourth solid layer 125 by plasma treatment. In this case, the fourth solid layer 125 may comprise the same material as the third solid layer 123. For example, the third solid layer 123 may comprise a titanium oxide, and the fourth solid layer 125 may also comprise a titanium oxide. The remaining portion 124 of the third solid layer 123 in step S22′ may maintain the thickness d in step S23′.
Referring to
In the method of filling a gap in
Since the TiO2 layer may be relatively thick, a portion of the TiO2 layer may still remain during the fluorination and, therefore, prevent the gap structure from being damaged by the fluorine during the fluorination.
In
Since the TiO2 layer may be relatively thin in
After the first cycle, the subsequent cyclic process may be processed in which a TiO2 layer with relatively thin thickness may be formed, followed by fluorinating the TiO2 layer may be repeated a plurality of times.
The flow rate (sccm) of the fluorine source and the fluorine source supply time (second) to protect the gap structure from the fluorine may be determined by the ratio of the fluorine flow amount (sccm·second) to the thickness (nm) of the TiO2 layer (i.e., a first solid layer) formed on the gap structure in the first cycle. The fluorine flow amount may be calculated by multiplying the flow rate (sccm) of the fluorine source by the fluorine source supply time (second).
In some embodiments, the ratio of the fluorine flow amount (sccm·second) to the thickness (nm) of the TiO2 layer formed in the first cycle (i.e., a first solid layer) may be about 1,000:1 sccm·second/nm or below to protect the gap structure from the fluorine. Therefore, the flow rate of the fluorine source and the supply time of the fluorine source may be determined based on the thickness of the TiO2 layer to be formed in the first cycle.
In another embodiments, the thickness of the TiO2 layer to be formed in the first cycle may be determined based on the flow rate of the fluorine source and the supply time of the fluorine source.
For instance, when the thickness of the TiO2 layer formed in the first cycle is 5 nm, the fluorine flow amount may be 5,000 sccm.second or below to meet the ratio 1,000:1 sccm·second/nm or below. In other words, the flow rate of the fluorine source and the supply time of the fluorine source may be determined within the range of the calculated fluorine flow amount. For instance, when the thickness of the TiO2 layer is 5 nm, 200 sccm of NF3 may be supplied for 25 seconds or below to protect the gap structure.
Referring to
For instance, the fluorination depth (e.g., a thickness of TiOxFy layer) may be less than 2 nm or 3 nm. Accordingly, forming about 5 nm or more thickness of TiO2 layer on the gap structure may be preferable as a protective layer, such that the thickness of the remaining TiO2 layer may be 3 nm or 2 nm after the fluorination.
Referring to
After forming the first TiO2 layer (i.e., a first solid layer), followed by fluorinating the first TiO2 layer into a first flowable layer (e.g., TiOxFy layer) to fill the gap, an oxygen source may be supplied to convert the first flowable layer into a second TiO2 layer (i.e., a second solid layer).
In the subsequent cycles (e.g., a second cycle or more), a third TiO2 layer with 2 nm thickness (i.e., a third solid layer) may be formed, followed by fluorinating the third TiO2 layer into a second flowable layer (e.g., TiOxFy layer) by supplying 100 sccm of NF3 for 45 seconds to fill the gap.
After that, an oxygen source may be supplied to convert the second flowable layer into a fourth TiO2 layer (i.e., a fourth solid layer). Even though the ratio of the fluorine flow amount (100 sccm·45 seconds) to the thickness (2 nm) of the third TiO2 layer formed in the subsequent cycles is 2,250:1 sccm·second/nm, greater than 1,000:1 sccm·second/nm, the gap structure may not be damaged since the first TiO2 layer may be formed thick enough to protect the gap structure in the first cycle.
Referring to
Referring to
After forming the TiO2 layer, a fluorination may be performed from T5 to T8 by supplying NF3 activated by the power at T6, such that a flowable TiOxFy layer may be formed on the TiO2 layer. The NF3 and Ar may be supplied at T5 to stabilize the gas flow in the reactor, followed by being activated by the power at T6 to fluorinate the TiO2 layer. After the power is turned off, the reactor may be purged without supplying a gas at T7 (i.e., a vacuum purge step by a vacuum pump only), followed by a purge step at T8 by supplying Ar and oxygen source.
Next to the fluorination, a conversion may be performed from T9 to T11 by supplying the oxygen source. The oxygen source may be activated at T10 by the power. In the conversion step, the flowable TiOxFy layer may be converted into the TiO2 layer.
The above gap filling process may be repeated a plurality of times (X times) until the gap is filled with the TiO2 layer.
Table 1 shows test conditions to perform the method of filling a gap according to an embodiment.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/619,809 filed Jan. 11, 2024 titled METHOD OF FILLING A GAP, the disclosure of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63619809 | Jan 2024 | US |
