阅读说明：本技术 在热氧化物品质的低温生长厚氧化物膜的方法 (Method for growing thick oxide films at low temperature of thermal oxide quality ) 是由 柯蒂斯·莱施克斯 约翰内斯·F·斯温伯格 本杰明·科伦坡 史蒂文·韦尔韦贝克 于 2020-02-23 设计创作，主要内容包括：于此描述的实施方案大体涉及在半导体基板上形成低k介电材料的方法。更具体地,于此描述的实施方案涉及在高压和低温下形成氧化硅膜的方法。形成氧化硅膜的方法包括以下步骤：将其上形成有含硅膜的基板装载到高压容器的处理区域中。方法进一步包括以下步骤：在含硅膜上形成氧化硅膜。在含硅膜上形成氧化硅膜的步骤包括以下步骤：将含硅膜在大于约1bar的压力下暴露于包括胺添加剂的氧化介质,并将高压容器保持在约100摄氏度和约550摄氏度之间的温度下。(Embodiments described herein generally relate to methods of forming low-k dielectric materials on semiconductor substrates. More particularly, embodiments described herein relate to methods of forming silicon oxide films at high pressures and low temperatures. The method of forming a silicon oxide film includes the steps of: the substrate having the silicon-containing film formed thereon is loaded into a processing region of a high-pressure vessel. The method further comprises the steps of: a silicon oxide film is formed on the silicon-containing film. The step of forming a silicon oxide film on a silicon-containing film comprises the steps of: the silicon-containing film is exposed to an oxidizing medium comprising an amine additive at a pressure greater than about 1bar and the high pressure vessel is maintained at a temperature between about 100 degrees celsius and about 550 degrees celsius.)

1. A method of forming a silicon oxide film, comprising the steps of:

loading a substrate having a silicon-containing film deposited thereon into a processing region of a high pressure vessel; and

forming a silicon oxide film on the silicon-containing film, comprising:

exposing the silicon-containing film to an oxidizing medium comprising an amine additive at a pressure greater than about 1 bar; and

maintaining the high pressure vessel at a temperature between about 100 degrees Celsius and about 550 degrees Celsius.

2. The method of claim 1, wherein the amine additive comprises ammonium or ammonia, and wherein the oxidizing medium comprises from about 1,000ppm to about 20,000ppm of the amine additive.

3. The method of claim 1, wherein the oxidizing medium is selected from the group consisting of steam, peroxide, oxygen, ozone, water vapor, heavy water, hydroxide-containing compounds, isotopes of oxygen, hydrogen, and combinations thereof.

4. The method of claim 1, wherein the silicon-containing film is a silicon nitride film, and wherein the oxidizing medium further comprises a hydrogen-based additive.

5. The method of claim 1, wherein the silicon oxide film has a uniform thickness of between about 20 angstroms and about 400 angstroms, and wherein the temperature is between about 400 degrees celsius and about 505 degrees celsius.

6. The method of claim 1, wherein the step of forming the silicon oxide film on the silicon-containing film is performed for a period of time between about 5 minutes and about 150 minutes.

7. A method of forming a conformal silicon oxide film, comprising:

depositing a silicon-containing film on a substrate comprising a plurality of vias, the silicon-containing film being deposited on each exposed surface of the substrate and the plurality of vias;

loading the substrate having the silicon-containing film deposited thereon into a processing region of a high pressure vessel; and

forming a conformal silicon oxide film on the silicon-containing film, comprising:

exposing the silicon-containing film to an oxidizing medium comprising an amine additive, wherein the oxidizing medium comprises from about 1,000ppm to about 20,000ppm of the amine additive; and

maintaining the high pressure vessel at a temperature of between about 100 degrees Celsius and about 550 degrees Celsius and at a pressure of between about 1bar and about 65 bar.

8. The method of claim 7, wherein the amine additive comprises ammonium or ammonia, and wherein the oxidizing medium comprises about 7,000ppm of the amine additive.

9. The method of claim 7, wherein the oxidizing medium is selected from the group consisting of steam, peroxide, oxygen, ozone, water vapor, heavy water, a hydroxide-containing compound, an oxygen isotope, a hydrogen isotope, and combinations thereof, and wherein the silicon-containing film comprises silicon or silicon nitride.

10. The method of claim 7, wherein the oxidizing medium is steam and the amine additive is ammonia, wherein the silicon-containing film is a silicon nitride film, and wherein the oxidizing medium further comprises a hydrogen-based additive.

11. The method of claim 7, wherein the step of forming the silicon oxide film on the silicon-containing film is performed at a temperature between about 400 degrees celsius and about 505 degrees celsius for a time period between about 5 minutes and about 150 minutes, and wherein the conformal silicon oxide film has a uniform thickness between about 20 angstroms and about 400 angstroms.

12. A method of forming a silicon oxide film, comprising the steps of:

loading a substrate having a silicon-containing film deposited thereon into a processing region of a high pressure vessel; and

forming a silicon oxide film on the silicon-containing film, comprising:

exposing the silicon-containing film to an oxidizing medium comprising ammonia, wherein the oxidizing medium is selected from the group consisting of steam, oxygen, and peroxide; and

maintaining the high pressure vessel at a temperature between about 400 degrees Celsius and about 505 degrees Celsius and at a pressure greater than about 10bar, wherein the silicon oxide film has a uniform thickness between about 100 angstroms and about 400 angstroms.

13. The method of claim 12, wherein the oxidizing medium comprises from about 1,000ppm to about 20,000ppm of the ammonia.

14. The method of claim 12, wherein the silicon-containing film comprises silicon or silicon nitride, and wherein the pressure is between about 10bar and about 60 bar.

15. The method of claim 12, wherein the step of forming the silicon oxide film on the silicon-containing film is performed for a period of time from about 5 minutes to about 120 minutes.

Technical Field

Embodiments described herein generally relate to methods for forming low-k dielectric materials on semiconductor substrates. More particularly, embodiments described herein relate to a method of forming a silicon oxide film at high pressure and low temperature using an oxidizing medium including an additive.

Background

The formation of semiconductor devices (such as memory devices, logic devices, microprocessors, etc.) involves the deposition of a low-k dielectric film over a semiconductor substrate. Low-k dielectric films are used to fabricate circuits of devices. Current dry or wet silicon oxidation techniques are typically performed at temperatures above 800 degrees celsius. However, materials deposited on semiconductor substrates may not be able to withstand temperatures greater than 800 degrees celsius. As a result, it may not be possible to deposit low-k dielectric films at temperatures above the thermal budget of 800 degrees celsius, and films deposited within the thermal budget often suffer from poor quality. In addition, current dry or wet silicon oxidation techniques are not capable of depositing high quality low-k dielectric films having a thickness greater than 100 angstroms.

Therefore, there is a need for a method of depositing high quality low-k dielectric films at temperatures that meet thermal budget targets.

Disclosure of Invention

Embodiments described herein generally relate to methods of forming low-k dielectric materials on semiconductor substrates. More particularly, embodiments described herein relate to a method of forming a silicon oxide film at high pressure and low temperature. The method of forming a silicon oxide film includes the steps of: the substrate having the silicon-containing film formed thereon is loaded into a processing region of a high-pressure vessel. The method further comprises the steps of: a silicon oxide film is formed on the silicon-containing film. The step of forming a silicon oxide film on a silicon-containing film comprises the steps of: exposing the silicon-containing film to an oxidizing medium comprising an amine additive at a pressure greater than about 1 bar; and maintaining the high pressure vessel at a temperature between about 100 degrees celsius and about 550 degrees celsius.

A method of forming a silicon oxide film includes the steps of: loading a substrate having a silicon-containing film deposited thereon into a processing region of a high pressure vessel; and forming a silicon oxide film on the silicon-containing film. The step of forming a silicon oxide film on a silicon-containing film comprises the steps of: exposing the silicon-containing film to an oxidizing medium comprising an amine additive at a pressure greater than about 1 bar; and maintaining the high pressure vessel at a temperature between about 100 degrees celsius and about 550 degrees celsius.

A method of forming a conformal (conformal) silicon oxide film comprising the steps of: a silicon-containing film is deposited on a substrate including a plurality of vias (via). A silicon-containing film is deposited on the substrate and each exposed surface of the plurality of vias. The method further comprises the steps of: loading a substrate having a silicon-containing film deposited thereon into a processing region of a high pressure vessel; and forming a conformal silicon oxide film on the silicon-containing film. The step of forming a conformal silicon oxide film on a silicon-containing film comprises the steps of: exposing the silicon-containing film to an oxidizing medium comprising an amine additive, wherein the oxidizing medium comprises about 1,000ppm to about 20,000ppm of the amine additive; and maintaining the high pressure vessel at a temperature between about 100 degrees celsius and about 550 degrees celsius and at a pressure between about 1bar and about 65 bar.

A method of forming a silicon oxide film includes the steps of: loading a substrate having a silicon-containing film deposited thereon into a processing region of a high pressure vessel; and forming a silicon oxide film on the silicon-containing film. The step of forming a silicon oxide film on a silicon-containing film comprises the steps of: exposing the silicon-containing film to an oxidizing medium comprising ammonia, wherein the oxidizing medium is selected from the group consisting of steam (steam), oxygen, and peroxide; and maintaining the high pressure vessel at a temperature between about 400 degrees celsius and about 505 degrees celsius and at a pressure greater than about 10 bar. The silicon oxide film has a uniform thickness between about 100 angstroms and about 400 angstroms.

Drawings

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

Fig. 1 depicts a simplified front cross-sectional view of one example of a high pressure vessel that may be used to implement one or more embodiments described herein.

Fig. 2A shows a semiconductor device having a silicon-containing film deposited thereon according to embodiments disclosed herein.

Fig. 2B-2D show various views of a semiconductor device having a conformal and uniform silicon oxide film formed thereon according to embodiments disclosed herein.

Fig. 3 is a flow chart showing a method of forming a conformal silicon oxide film according to one embodiment.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

Embodiments described herein generally relate to methods of forming low-k dielectric materials on semiconductor substrates. More particularly, embodiments described herein relate to a method of forming a silicon oxide film at high pressure and low temperature. The method of forming a silicon oxide film includes the steps of: the substrate having the silicon-containing film formed thereon is loaded into a processing region of a high-pressure vessel. The method further comprises the steps of: a silicon oxide film is formed on the silicon-containing film. The step of forming a silicon oxide film on a silicon-containing film comprises the steps of: the silicon-containing film is exposed to an oxidizing medium comprising an amine additive at a pressure greater than about 1bar and the high pressure vessel is maintained at a temperature between about 100 degrees celsius and about 550 degrees celsius.

Embodiments described herein will be described below with reference to a high pressure oxidation process that may be performed using a high pressure oxidation system. In fig. 1, the device descriptions described herein are illustrative and should not be read or construed as limiting the scope of the embodiments described herein.

Fig. 1 is a simplified front cross-sectional view of a high pressure vessel 100 for high pressure annealing. The high pressure vessel 100 has a body 110, the body 110 having an outer surface 112 enclosing a processing region 115 and an inner surface 113. In some embodiments, such as fig. 1, the body 110 has a circular cross-section, but in other embodiments, the cross-section of the body 110 may be rectangular or any closed shape. The outer surface 112 of the body 110 may be made of Corrosion Resistant Steel (CRS), such as, but not limited to, stainless steel. In one embodiment, the inner surface 113 of the body 110 is made of a nickel-based steel alloy (such as, but not limited to, nickel-based steel alloys) that exhibits high corrosion resistance) And (4) preparing.

The high pressure vessel 100 has a door 120 configured to sealably enclose the processing region 115 within the body 110 such that the processing region 115 is accessible when the door 120 is open. The high pressure seal 122 is used to seal the door 120 to the body 110 in order to seal the processing region 115 for processing. The high pressure seal 122 may be made of a polymer, such as, but not limited to, a perfluoroelastomer. A cooling channel 124 is disposed on the door 120 adjacent the high pressure seal 122 to maintain the high pressure seal 122 below a maximum safe operating temperature of the high pressure seal 122 during processing. A coolant (such as, but not limited to, an inert, dielectric, and/or high performance heat transfer fluid) may be circulated within the cooling channel 124 to maintain the high pressure seal 122 at a temperature between about 150 degrees celsius and about 250 degrees celsius. The flow of coolant within the cooling channels 124 is controlled by the controller 180 through feedback received from the temperature sensor 116 or a flow sensor (not shown).

The high pressure vessel 100 has a port 117 through the body 110. The port 117 has a tube 118 therethrough, the tube 118 being coupled to a heater 119. One end of the tube 118 is connected to the processing region 115. The other end of the tube 118 branches into an inlet conduit 157 and an outlet conduit 161. The inlet conduit 157 is fluidly connected to the gas panel 150 via an isolation valve 155. The inlet conduit 157 is coupled to a heater 158. The outlet conduit 161 is fluidly connected to the condenser 160 via an isolation valve 165. The outlet conduit 161 is coupled to a heater 162. Heaters 119, 158, and 162 are configured to maintain a process gas (such as an oxidizing medium) flowing through tube 118, inlet conduit 157, and outlet conduit 161, respectively, at a temperature between a condensation point of the process gas and about 250 degrees celsius. Heaters 119, 158, and 162 are powered by power supply 145.

The gas panel 150 is configured to provide a process gas (such as an oxidizing medium) under pressure into an inlet conduit 157 for delivery into the processing region 115 through the tube 118. The oxidizing medium includes an amine additive. The pressure of the process gas introduced into the processing region 115 is monitored by a pressure sensor 114 coupled to the body 110. The condenser 160 is fluidly coupled to the cooling fluid and is configured to condense gaseous products flowing through the outlet conduit 161 after being removed from the processing region 115 via the tube 118. The condenser 160 converts the gaseous products from the gas phase to the liquid phase. A pump 170 is fluidly connected to the condenser 160 and draws the liquefied product from the condenser 160. The operation of the gas panel 150, the condenser 160, and the pump 170 is controlled by a controller 180.

The isolation valves 155 and 165 are configured to allow only one fluid to flow through the tube 118 into the processing region 115 at a time. When the isolation valve 155 is open, the isolation valve 165 closes, allowing process gas flowing through the inlet conduit 157 to enter the processing region 115, thereby preventing the process gas from flowing into the condenser 160. On the other hand, when the isolation valve 165 is open, the isolation valve 155 is closed such that gaseous products are removed from the processing region 115 and flow through the outlet conduit 161, thereby preventing the gaseous products from flowing into the gas panel 150.

One or more heaters 140a, 140b (collectively 140) are disposed on the body 110 and are configured to heat the processing region 115 within the high pressure vessel 100. In some embodiments, as shown in fig. 1, the heater 140 is disposed on the outer surface 112 of the body 110, although in other embodiments, the heater 140 may be disposed on the inner surface 113 of the body 110. Each of the heaters 140 may be a resistive coil, a lamp, a ceramic heater, a graphite-based Carbon Fiber Composite (CFC) heater, a stainless steel heater, or an aluminum heater. The heater 140 is powered by a power source 145. The power to the heater 140 is controlled by the controller 180 through feedback received from the temperature sensor 116. A temperature sensor 116 is coupled to the body 110 and monitors the temperature of the processing region 115.

A cassette (cassette)130 coupled to an actuator (not shown) is moved into and out of the processing region 115. The cartridge 130 has a top surface 132, a bottom surface 134, and a wall 136. The wall 136 of the cassette 130 has a plurality of substrate storage slots 138. Each substrate reservoir 138 is evenly spaced along the wall 136 of the cassette 130. Each substrate storage slot 138 is configured to hold a substrate 135 therein. The cassette 130 may have as many as fifty substrate storage slots 138 for holding substrates 135. The cassette 130 provides an efficient carrier for moving the plurality of substrates 135 into and out of the high pressure vessel 100 and for processing the plurality of substrates 135 in the processing region 115.

The controller 180 controls the operation of the high pressure vessel 100. The controller 180 controls the operation of the gas panel 150, the condenser 160, the pump 170, the isolation valves 155 and 165, and the power supply 145. The controller 180 is also communicatively connected to the temperature sensor 116, the pressure sensor 114, and the cooling channel 124. The controller 180 includes a Central Processing Unit (CPU)182, a memory 184, and support circuits 186. The CPU182 may be any form of a general purpose computer processor that can be used in an industrial environment. The memory 184 may be random access memory, read only memory, floppy or hard disk drive, or other form of digital storage. The support circuits 186 are conventionally coupled to the CPU182 and may include cache memory (cache), clock circuits, input/output systems, power supplies, and the like.

The high pressure vessel 100 provides a convenient chamber to perform a method of forming a silicon oxide film on a plurality of substrates 135 at a temperature of 550 degrees celsius or less. The heater 140 is energized to preheat the high pressure vessel 100 and maintain the processing region 115 at a temperature of about 550 degrees celsius or less. At the same time, heaters 119, 158 and 162 are energized to preheat tube 118, inlet conduit 157 and outlet conduit 161, respectively.

A plurality of substrates 135 are loaded on the cassette 130. The door 120 of the high pressure vessel 100 is opened to move the cassette 130 into the processing region 115. The door 120 is then hermetically closed to change the high pressure vessel 100 into a high pressure vessel. Once the door 120 is closed, the high pressure seal 122 ensures that there is no pressure leak from the processing region 115.

A process gas (i.e., an oxidizing medium including an amine additive) is provided into the processing region 115 inside the high pressure vessel 100 by a gas panel 150. The isolation valve 155 is opened by the controller 180 to allow process gas to flow into the processing region 115 through the inlet conduit 157 and the pipe 118. The process gas is introduced at a flow rate, for example, between about 500sccm and about 2000 sccm. At this time, the isolation valve 165 remains closed. In some embodiments, the pressure in the high pressure vessel 100 is gradually increased. The high pressure effectively drives the oxygen into the silicon-containing film into a more fully oxidized state, particularly in the deeper portions of the trench.

In some embodiments described herein, the process gas is steam that includes the amine additive at a pressure between about 1bar and about 65bar (e.g., between about 35bar and about 65 bar; or between about 40bar and 60 bar). However, in other embodiments, other oxidizing media (such as, but not limited to, ozone, oxygen, peroxides, or hydroxide-containing compounds) may be used with or in place of steam. The amine additive added to the oxidation medium may be ammonium or ammonia. When the gas panel 150 releases sufficient vapor, the controller 180 closes the isolation valve 155.

During processing of the substrate 135, the processing region 115, as well as the inlet conduit 157, outlet conduit 161, and tube 118, are maintained at a temperature and pressure such that the process gases remain in a gas phase. Under the applied pressure, the temperature of the processing region 115, as well as the inlet conduit 157, outlet conduit 161, and tube 118, is maintained above the condensation point of the processing gas (e.g., 100 degrees celsius), but at a temperature of 550 degrees celsius or less. The processing region 115, as well as the inlet conduit 157, outlet conduit 161 and tube 118, are maintained at a pressure less than the condensing pressure of the processing gas at the application temperature. The process gas is selected accordingly. In the embodiments described herein, steam at a pressure between about 1bar and about 65bar is an effective treatment gas when the high pressure vessel is maintained at a temperature between about 100 degrees celsius and about 550 degrees celsius. This ensures that the vapor does not condense into water, which is detrimental to the silicon film deposited on the substrate 135.

When the film is observed to have the target density, the process is complete, as evidenced by testing the wet etch rate and the leakage and breakdown characteristics of the film. The isolation valve 165 is then opened to allow the process gas to flow from the process region 115 through the pipe 118 and the outlet conduit 161 into the condenser 160. The process gas is condensed to a liquid phase in condenser 160. The liquefied process gas is then removed by pump 170. When the liquefied process gas is completely removed, the isolation valve 165 is closed. The heaters 140, 119, 158 and 162 are then powered down. The door 120 of the high pressure vessel 100 is then opened to remove the cassette 130 from the processing region 115.

Fig. 2A illustrates a semiconductor device 200 according to one or more embodiments described herein, the semiconductor device 200 including a substrate 202 and a silicon-containing film 208 deposited on the substrate 202. As shown in fig. 1, when the substrate 202 is loaded onto the cassette 130, the substrate 202 may be used instead of each substrate 135. One or more openings or vias 204 may be formed in the substrate 202. Although only one via 204 is shown in the semiconductor device 200, a plurality of vias 204 may be included. In such embodiments, each via 204 of the plurality of vias may have the same dimensions, such as having a depth of about 10 μm. Additionally, the sides 214 and bottom 216 of the via 204 may be patterned and may not be planar as shown. Silicon-containing film 208 can be deposited on each exposed surface (i.e., top surface 212, sides 214, and bottom 216) of substrate 202 and via 204. The silicon-containing film 208 can be deposited using Atomic Layer Deposition (ALD). Silicon-containing film 208 can be comprised of silicon or silicon nitride.

The substrate 202 may contain one or more materials used in forming semiconductor devices, such as metal contacts, trench isolations, gates, bitlines (bitlines) or any other interconnect features. The substrate 202 may include one or more metal layers, one or more dielectric materials, semiconductor materials, and combinations thereof for fabricating semiconductor devices. For example, the substrate 202 may include an oxide material, a nitride material, a polysilicon material, or the like, depending on the application. In one embodiment targeted for memory applications, the substrate 202 may comprise a silicon substrate material, an oxide material, and a nitride material, with or without polysilicon sandwiched therebetween.

In another embodiment, the substrate 202 may include a plurality of alternating oxide and nitride materials (i.e., oxide-nitride-oxide (ONO)) deposited on a surface of the substrate (not shown). In various embodiments, the substrate 202 may include a plurality of alternating oxide and nitride materials, one or more oxide or nitride materials, polycrystalline or amorphous silicon materials, oxides alternating with amorphous silicon, oxides alternating with polycrystalline silicon, undoped silicon alternating with doped silicon, undoped polycrystalline silicon alternating with doped polycrystalline silicon, or undoped amorphous silicon alternating with doped amorphous silicon. The substrate 202 may be any substrate or material surface on which film processing is performed. For example, the substrate 202 may be a material such as crystalline silicon, silicon oxide, silicon oxynitride, silicon nitride, strained silicon, silicon germanium, tungsten, titanium nitride, doped or undoped polysilicon, doped or undoped silicon wafers, and patterned or unpatterned silicon wafers, silicon-on-insulator (SOI), carbon doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, low-k dielectrics, and combinations thereof.

Fig. 2B illustrates the semiconductor device 200 with a conformal silicon oxide film 206 formed in the via 204 according to one or more embodiments described herein. The silicon oxide film 206 is formed on the substrate 202 and the silicon-containing film 208 at a temperature of 550 degrees celsius or less, such as at a temperature of about 350 degrees celsius to about 505 degrees celsius. Silicon oxide film 206 is formed using a high pressure anneal at a pressure of 1bar or more, such as about 35bar to about 65bar, in an oxidizing medium including an amine additive.

The oxidizing medium may include steam, oxygen, peroxide, etc., and the amine additive may include ammonium (NH)₄) Or ammonia (NH)₃). The oxidizing medium may include about 1,000ppm to about 20,000ppm of the amine additive, such as about 7,000 ppm. In one embodiment, steam is used as the oxidizing medium and about 7,000ppm NH is used₃As an amine additive. When reacting a film comprising silicon nitride, a hydrogen-based additive may be added to the oxidizing medium. When making the bagWhen reacting silicon nitride including films, a hydrogen-based additive may be added in addition to or as a substitute for the amine additive. The hydrogen-based additive may include pure hydrogen (H)₂) Or trace amounts of hydrogen as a component of the inert gas. The amine and/or hydrogen-based additive added to the oxidizing medium can increase the oxidation rate by a factor of about 2 to 3 compared to a high temperature rapid thermal oxidation film. In one embodiment, the annealing process used to form silicon oxide film 206 is performed at a pressure of about 40bar to about 60bar for about one hour.

Silicon-containing film 208 is disposed between substrate 202 and silicon oxide film 206; however, after forming silicon oxide film 206, silicon-containing film 208 may have a smaller thickness. In one embodiment, silicon-containing film 208 is fully oxidized such that silicon-containing film 208 is no longer disposed between silicon oxide film 206 and substrate 202 (i.e., silicon oxide film 206 can be in contact with substrate 202). Although not shown, silicon oxide film 206 and/or silicon-containing film 208 can be disposed on surface 212 of substrate 202.

Fig. 2C shows an enlarged cross-sectional view through the top portion of the semiconductor device 200 at line 2C-2C. The 2C-2C line may be about 500nm below the surface 212 of the semiconductor device 200. Fig. 2D shows an enlarged cross-sectional view through the bottom portion of the semiconductor device 200 at the 2D-2D line. The 2D-2D line may be about 500nm above the bottom 216 of the semiconductor device 200. The silicon oxide film 206 of the top portion of fig. 2C has a thickness of 210A, while the silicon oxide film 206 of the bottom portion of fig. 2D has a thickness of 210B (generally 210).

As shown in fig. 2C and 2D, the thickness 210A of the top portion of silicon oxide film 206 is about the same as the thickness 210B of the bottom portion of silicon oxide film 206. Silicon oxide film 206 has an approximately uniform thickness 210 at both the top and bottom portions of via 204, representing approximately 100% conformality (i.e., the ratio of thickness 210A of the top portion to thickness 210B of the bottom portion) of silicon oxide layer 206. Silicon oxide film 206 formed using an oxidizing medium comprising an amine additive at a temperature less than about 550 degrees celsius and a pressure greater than 1bar has a near uniform conformality of greater than about 90% on sides 214 and bottom 216 of via 204. Silicon oxide film 206 has a uniform thickness 210 of about 20 angstroms to about 400 angstroms, such as about 150 angstroms to about 400 angstroms.

Fig. 3 depicts a process flow diagram of a method 300 for forming a silicon oxide film on a substrate according to one or more embodiments described herein. The substrate may be the substrate 135 as depicted in fig. 1 or the substrate 202 as depicted in fig. 2A-2D. For clarity, the method 300 will be described with reference to elements of the semiconductor device 200 of fig. 2A-2D.

The method 300 begins at operation 310 by loading a substrate 202 having a silicon-containing film 208 (shown in fig. 2A) deposited thereon into a high pressure vessel. The high pressure vessel may be the high pressure vessel 100 depicted in fig. 1. The substrate 202 may be placed in a cassette, such as the cassette 130 shown in fig. 1. A silicon-containing film 208 is deposited on each exposed side or surface 212, 214, 216 of the substrate 202 and the vias 204 prior to loading the substrate 202 into the high pressure vessel. The silicon-containing film 208 can be deposited using ALD. Silicon-containing film 208 can be comprised of silicon or silicon nitride. The substrate 202 may be composed of any of the materials discussed above in fig. 2A-2D.

In one embodiment, similar to that shown in fig. 2A-2D, the surface 212 of the substrate 202 includes a patterned structure, e.g., a surface having trenches, holes, or vias 204 formed therein. In such embodiments, the silicon-containing film 208 is disposed on the sides 214 and the bottom 216 of the via 204. Alternatively, the surface 212 of the substrate 202 may be substantially planar. The substrate 202 may also have a substantially planar surface 212, the substantially planar surface 212 having structures formed thereon or therein at a target height. Although the surface 212 of the substrate 202 may include trenches, holes, vias, or bumps (elevation), the pattern of the surface 212 will be referred to as vias throughout the specification, and the term "vias" is not intended to be limiting.

At operation 320, the substrate 202 is exposed to an oxidizing medium including an amine additive at a target temperature between a condensation point of the oxidizing medium (e.g., about 100 degrees celsius) and about 550 degrees celsius and a pressure greater than 1 bar. In one embodiment, the target temperature is between about 100 degrees Celsius and about 550 degrees Celsius (e.g., between about 350 degrees Celsius and about 520 degrees Celsius; or between about 400 degrees Celsius and about 505 degrees Celsius). The temperature may be raised to a target temperature using the heaters 140a, 140 b. In addition to increasing the temperature, the pressure may also be increased to a target pressure. In one embodiment, the pressure is between about 1bar and about 65bar (e.g., between about 30bar and about 65 bar; or between about 40bar and about 60 bar).

In one embodiment, the oxidizing medium is selected from the group consisting of steam, ozone, oxygen, water vapor, heavy water, peroxides, hydroxide-containing compounds, isotopes of oxygen (14, 15, 17, 18, etc.) and hydrogen (1, 2, 3), and combinations thereof. The peroxide may be hydrogen peroxide in the gas phase. In some embodiments, the oxidizing medium comprises hydroxide ions, such as, but not limited to, water vapor or heavy water in vapor form. The amine additive may consist of ammonium or ammonia. The oxidizing medium may include about 1,000ppm to about 20,000ppm of the amine additive, such as about 7,000 ppm. In one embodiment, steam is used as the oxidizing medium and about 7,000ppm NH is used₃As an amine additive. When reacting a film comprising silicon nitride, a hydrogen-based additive may be added to the oxidizing medium. When reacting silicon nitride including a film, a hydrogen-based additive may be added in addition to or as a substitute for the amine additive. The hydrogen-based additive may include pure hydrogen (H)₂) Or trace amounts of hydrogen as a component of the inert gas. The amine and/or hydrogen-based additive added to the oxidizing medium can increase the oxidation rate by a factor of about 2 to 3 compared to a high temperature rapid thermal oxidation film.

In some embodiments, the substrate 202 or plurality of substrates is exposed to steam including an amine additive at a pressure between about 5bar to about 60bar, wherein the pressure may be gradually increased from 5bar to about 60 bar. In some embodiments, the steam comprising the amine additive is introduced into the high pressure vessel at a flow rate of, for example, between about 500sccm and about 5,000sccm (e.g., between about 500sccm and about 5,000 sccm; or between about 500sccm and about 2,000 sccm). In one embodiment, water vapor comprising the amine additive is injected into the high pressure vessel and, when heated in the high pressure vessel, the water vapor forms steam comprising the amine additive. In another embodiment, water or water vapor including the amine additive may be present in the high pressure vessel prior to heating to the target temperature. As the high pressure vessel is heated to the target temperature, the water or water vapor present in the high pressure vessel forms steam that includes the amine additive.

At operation 330, a silicon oxide film 206 is formed on the substrate 202. The silicon oxide film 206 is formed as a conformal or uniform layer. Silicon oxide film 206 is uniformly formed on sides 214 and bottom 216 of via 204 and on surface 212 of substrate 202. Silicon oxide film 206 can be deposited to have greater than about 90% conformality on sides 214 and bottom 216 of via 204, as shown in fig. 2A-2D. Silicon oxide film 206 can have a thickness 210 of about 20 angstroms to about 400 angstroms, such as about 150 angstroms to about 400 angstroms.

At operation 330, the high pressure vessel is maintained at a temperature between the condensation point of the oxidizing medium and about 550 degrees celsius while the substrate 202 with the silicon-containing film 208 is exposed to the oxidizing medium comprising the amine additive to form the silicon oxide film 206. In one embodiment, where steam including an amine additive is used at a pressure of about 40bar to about 60bar, the temperature of the high pressure vessel is maintained between about 400 degrees celsius and about 505 degrees celsius. In some embodiments, the forming of the silicon oxide film 206 on the substrate 202 of operation 330 is performed for a time period of between about 5 minutes and about 150 minutes (such as about 30 minutes to about 120 minutes). In at least one embodiment, silicon-containing film 208 is fully oxidized with an oxidizing medium comprising an amine additive for about 120 minutes at a temperature between about 400 degrees celsius and about 505 degrees celsius and a pressure of about 60bar such that silicon-containing film 208 is no longer disposed between substrate 202 and silicon oxide layer 206.

Applying an oxidizing medium comprising an amine additive at high pressure, such as steam comprising ammonia, allows a high concentration of oxidizing species to penetrate deep into the silicon-containing film from the oxidizing medium, such that the oxidizing species can generate more silicon oxide film material via oxidation. Without being bound by theory, it is believed that the high pressure inside the high pressure vessel drives the diffusion of the oxidizing species into the deeper vias. In addition, it is believed that the presence of the amine additive in the steam allows the target pressure to be achieved at a faster rate and increases the oxidation rate by a factor of 2-3 compared to high temperature rapid thermal oxidation of the film.

The quality of silicon oxide film 206 can be verified by comparing the wet etch rate of silicon oxide film 206 formed using an oxidizing medium including an amine additive at a temperature less than 550 degrees celsius and a pressure greater than 1bar with the wet etch rate of a silicon oxide film formed without an amine additive at a temperature in excess of 800 degrees celsius at a low pressure (i.e., a high temperature rapid thermal oxide film). When both silicon oxide film 206 having a thickness greater than about 20 angstroms and the high temperature rapid thermal oxide film having the same thickness are wet etched, the wet etch rate is about the same for both films. In one embodiment, both silicon oxide film 206 and the high temperature rapid thermal oxide film have a wet etch rate of about 26 a/min to about 32 a/min.

In addition, the quality of silicon oxide film 206 can be further verified by comparing the leakage and capacitance equivalent thickness of silicon oxide film 206 formed using an oxidizing medium including an amine additive at temperatures below 550 degrees celsius and pressures greater than 1bar with a high temperature rapid thermal oxide film. When comparing the leakage of silicon oxide film 206 having a thickness greater than about 20 angstroms with the leakage of a high temperature rapid thermal oxide film having the same thickness, both silicon oxide films are disposed along the thermal trend line or extrapolated thermal trend line of the voltage leakage versus thickness graph. Thus, the leakage and capacitance equivalent thickness of the silicon oxide film 206 is about the same as or comparable to that of the high temperature rapid thermal oxide film. In one embodiment, silicon oxide film 206 and the high temperature rapid thermal oxide film each have a leakage versus capacitance equivalent thickness of about 0.22V/angstrom to about 0.25V/angstrom.

Thus, for a process performed at a relatively low temperature of 550 degrees celsius or less, the film quality improvement is substantially similar to a process performed at a temperature of 800 degrees celsius or more at a low pressure. Processing performed at relatively low temperatures of 550 degrees celsius or less with an oxidizing medium including an amine additive enables a silicon oxide layer to be deposited uniformly, including deposition on substrates having challenging or non-planar structures.

Furthermore, forming the silicon oxide film using an oxidizing medium comprising an amine and/or hydrogen-based additive at a temperature of less than 550 degrees celsius and a pressure of greater than 1bar enables the silicon oxide film to achieve a thickness greater than the capability of a high temperature rapid thermal oxidation process while maintaining high quality. Thus, depositing a silicon oxide film using an oxidizing medium including an amine additive at a temperature less than 550 degrees celsius and a pressure greater than 1bar produces a conformal or uniform silicon oxide film having an increased oxidation rate and having the same quality as a high temperature rapid thermal oxide film.

Further, depositing the silicon oxide film at a temperature less than about 550 degrees celsius with an oxidizing medium including an amine additive expands the process window for forming the silicon oxide film as the process window is no longer limited to temperatures of about 800 degrees celsius or greater. Expanding the process window increases the capabilities of current tools for forming silicon oxide films, thereby reducing overall resources.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.