阅读说明：本技术 在衬底上沉积的膜的质量改进 (Quality improvement of films deposited on substrates ) 是由 P·曼纳 A·B·玛里克 K·莱斯彻基什 S·文哈弗贝克 S·卡玛斯 Z·王 H·张 于 2018-05-29 设计创作，主要内容包括：本公开的实施方式整体涉及一种在小于250摄氏度的温度下处理半导体衬底的方法。在一个实施方式中,所述方法包括：将具有沉积的膜的所述衬底装载到压力容器中；在大于约2巴的压力下将所述衬底暴露于包括氧化剂的处理气体；以及维持所述压力容器处于在所述处理气体的冷凝点与约250摄氏度之间的温度。(Embodiments of the present disclosure generally relate to a method of processing a semiconductor substrate at a temperature of less than 250 degrees celsius. In one embodiment, the method comprises: loading the substrate with the deposited film into a pressure vessel; exposing the substrate to a process gas comprising an oxidant at a pressure greater than about 2 bar; and maintaining the pressure vessel at a temperature between a condensation point of the process gas and about 250 degrees celsius.)

1. A method of processing a substrate:

loading the substrate, having a film deposited thereon, into a pressure vessel;

exposing the substrate to a process gas comprising an oxidant at a pressure greater than about 2 bar; and

maintaining the pressure vessel at a temperature between a condensation point of the process gas and about 250 degrees Celsius.

2. The method of claim 1, wherein the membrane comprises one or more of:

metal oxide, metal nitride, metal oxynitride, silicon oxide, silicon nitride, or silicon oxynitride.

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

4. The method of claim 1, wherein the oxidizing agent comprises hydroxide ions.

5. The method of claim 1, wherein the oxidizing agent is a peroxide.

6. The method of claim 1, wherein exposing the substrate to a process gas comprises:

exposing the substrate to a vapor at a pressure of about 5 bar to about 35 bar.

7. The method of claim 6, wherein the temperature of the pressure vessel is maintained between about 150 degrees Celsius and about 250 degrees Celsius.

8. A method of processing a substrate, comprising:

loading a cassette having a plurality of substrates, each having a film deposited thereon, into a pressure vessel;

exposing the plurality of substrates to a process gas comprising an oxidizing agent at a pressure greater than about 2 bar; and

maintaining the pressure vessel at a temperature between a condensation point of the process gas and about 250 degrees Celsius.

9. The method of claim 8, wherein the membrane comprises one or more of:

metal oxide, metal nitride, metal oxynitride, silicon oxide, silicon nitride, or silicon oxynitride.

10. The method of claim 8, wherein the oxidizing agent is selected from the group consisting of: ozone, oxygen, water vapor, heavy water, peroxide, hydroxide-containing compounds, isotopes of oxygen and hydrogen.

11. The method of claim 8, wherein the oxidizing agent comprises hydroxide ions.

12. The method of claim 8, wherein the oxidizing agent is a peroxide.

13. The method of claim 8, wherein exposing the plurality of substrates to a process gas comprises:

exposing the plurality of substrates to a vapor at a pressure of about 5 bar to about 35 bar.

14. A method of sequentially processing a substrate, comprising:

opening the first valve;

flowing a process gas comprising an oxidant into a chamber having a substrate with a film disposed therein at a pressure greater than about 2 bar;

exposing the process gas to the substrate, wherein the process gas is maintained at a temperature above a condensation point temperature of the process gas and below about 250 degrees Celsius;

closing the first valve; and

opening a second valve to remove the process gas from the chamber.

15. The method of claim 14, wherein the oxidizing agent is selected from the group consisting of: ozone, oxygen, water vapor, heavy water, peroxide, hydroxide-containing compounds, isotopes of oxygen and hydrogen.

Technical Field

Embodiments of the present disclosure relate generally to the fabrication of integrated circuits, and in particular to methods of improving the quality of films deposited on semiconductor substrates.

Background

Disclosure of Invention

Embodiments of the present disclosure generally relate to a method of processing a semiconductor substrate at a temperature of less than 250 degrees celsius. In one embodiment, the method comprises: loading the substrate with the deposited film into a pressure vessel; exposing the substrate to a process gas comprising an oxidant at a pressure greater than about 2 bar; and maintaining the pressure vessel at a temperature between a condensation point of the process gas and about 250 degrees celsius.

In another embodiment of the present disclosure, the method comprises: loading a cassette having a plurality of substrates, each having a film deposited thereon, into a pressure vessel; exposing the plurality of substrates to a process gas comprising an oxidizing agent at a pressure greater than about 2 bar; and maintaining the pressure vessel at a temperature between a condensation point of the process gas and about 250 degrees celsius.

In yet another embodiment of the present disclosure, the method comprises: opening the first valve; flowing a process gas comprising an oxidant into a chamber having a substrate with a film disposed therein at a pressure greater than about 2 bar; exposing the process gas to the substrate, wherein the process gas is maintained at a temperature above a condensation point temperature of the process gas and below about 250 degrees Celsius; closing the first valve; and opening a second valve to remove the process gas from the chamber.

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 disclosure may admit to other equally effective embodiments.

FIG. 1 is a simplified front cross-sectional view of a pressure vessel for improving the quality of films deposited on a substrate at temperatures less than 250 degrees Celsius.

Fig. 2A is a simplified cross-sectional view of a low quality film deposited on a semiconductor substrate.

Fig. 2B is a simplified cross-sectional view of a membrane having improved quality after performing the methods described herein.

Fig. 3 is a block diagram of a method of improving the quality of a film deposited on a semiconductor substrate at a temperature of less than 250 degrees celsius.

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/or features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

Embodiments of the present disclosure generally relate to a method of improving the quality of films deposited on semiconductor substrates at temperatures below 250 degrees celsius. The method repairs areas of poor film deposited at temperatures below 200 degrees celsius. In some embodiments, commercially available from Applied Materials, Inc., Santa Clara, Calif. is usedAvila^TMA plasma enhanced chemical vapor deposition chamber (PECVD) chamber to produce the film. In other embodiments, the film may be produced by any Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD) technique, including in chambers produced by other manufacturers. During the post-deposition annealing process disclosed herein, the film is exposed to a process gas comprising an oxidizing agent at high pressure to increase the density of the film. The process gas penetrates deeply into the film layer to reduce porosity through the oxidation process, thereby enhancing the density and quality of the film deposited on the substrate. For the purpose of performing the high pressure annealing process, a batch processing chamber, such as but not limited to the pressure vessel 100 shown in fig. 1 and described herein, is utilized. However, the methods described herein are equally applicable to a single substrate disposed in a single substrate chamber.

Fig. 1 is a simplified front cross-sectional view of a pressure vessel 100 for a high pressure annealing process. The pressure vessel 100 has a body 110, the body 110 having an outer surface 112 and an inner surface 113 enclosing a processing region 115. In some embodiments, such as in 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)Not limited to stainless steel). The inner surface 113 of the body 110 may be made of a nickel-based steel alloy (such as, but not limited to, nickel-based alloys) exhibiting high corrosion resistance) And (4) preparing.

The pressure vessel 100 has a door 120, the door 120 being 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 channels 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 passage 124 is controlled by the controller 180 through feedback received from the temperature sensor 116 or a flow sensor (not shown).

The pressure vessel 100 has a port 117 through the body 110. The port 117 has a conduit 118 therethrough, the conduit 118 being coupled to a heater 119. One end of the conduit 118 is connected to the processing region 115. The other end of the conduit 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. The heaters 119, 158, and 162 are configured to maintain the process gas flowing through the conduit 118, the inlet conduit 157, and the outlet conduit 161, respectively, at a temperature between the 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 process gas including an oxidant under pressure into the inlet conduit 157 for delivery into the processing region 115 through the conduit 118. 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 the gaseous products flowing through the outlet conduit 161 after being removed from the processing region 115 through the conduit 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 pumps 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.

Isolation valves 155 and 165 are configured to allow only one fluid to flow through conduit 118 into treatment area 115 at a time. When the isolation valve 155 is open, the isolation valve 165 closes such that process gas flowing through the inlet conduit 157 enters 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 140 are disposed on the body 110 and are configured to heat the processing region 115 within the pressure vessel 100. In some embodiments, the heater 140 is disposed on the outer surface 112 of the body 110, as shown in fig. 1, but 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, an aluminum heater, or the like. The heater 140 is powered by a power source 145. Power to heater 140 is controlled by controller 180 through feedback received from temperature sensor 116. A temperature sensor 116 is coupled to the body 110 and monitors the temperature of the processing region 115.

A 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 storage slot 138 is evenly spaced along the wall 136 of the cassette 130. Each substrate storage tank 138 is configured to hold a substrate 135 therein. The cassette 130 may have up to fifty substrate storage slots 138 for holding substrates 135. The cassette 130 provides an efficient carrier for transporting a plurality of substrates 135 into and out of the pressure vessel 100 and for processing a plurality of substrates 135 in the processing region 115.

The controller 180 controls the operation of the 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 passage 124. The controller 180 includes a Central Processing Unit (CPU)182, a memory 184, and support circuits 186. The CPU 182 may be any form of a general purpose computer processor useful 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 CPU 182 and may include cache, clock circuits, input/output systems, power supplies, and the like.

The pressure vessel 100 provides a convenient chamber to perform a method of improving the quality of films deposited on a plurality of substrates 135 at temperatures less than 250 degrees celsius. During operation, the heater 140 is energized to preheat the pressure vessel 100 and maintain the processing region 115 at a temperature below 250 degrees celsius. At the same time, heaters 119, 158 and 162 are energized to preheat conduit 118, inlet conduit 157 and outlet conduit 161, respectively.

A plurality of substrates 135 are loaded on the cassette 130. When the substrates 135 are loaded on the cassette 130, each of the substrates 135 is considered as a semiconductor substrate 200 in fig. 2A. Fig. 2A shows a simplified cross-sectional view of a low quality film deposited on a semiconductor substrate 200 similar to substrate 135 prior to the substrate 135 being loaded onto cassette 130. The substrate 200 has a film 210 deposited thereon at a temperature of less than 200 degrees celsius. In some embodiments, film 210 may also include silicon oxide, silicon nitride, or silicon oxynitride. In other embodiments, film 210 may also include a metal oxide, a metal nitride, or a metal oxynitride. The quality of the film 210 is low due to the presence of the plurality of pores 225 within the trenches 220 of the film 210. The voids 225 are open spaces located deep within the trenches 220 of the film 210 and result in a low density of the film 210.

The door 120 of the pressure vessel 100 is opened to move the cassette 130 into the processing region 115. The door 120 is then sealingly closed to provide a high pressure chamber within the pressure vessel 100. Once the door 120 is closed, the seal 122 ensures that there is no pressure leak from the processing region 115.

Process gas is provided to the process region 115 within the pressure vessel 100 through the gas panel 150. The isolation valve 155 is opened by the controller 180 to allow process gas to flow through the inlet conduit 157 and the conduit 118 into the processing region 115. The process gas is introduced at a flow rate of between about 500sccm and about 2000sccm for a period of between about 1 minute and about 10 minutes. At this time, the isolation valve 165 remains closed. The process gas is an oxidizing agent that is flowed into the processing region 115 at a high pressure. The pressure of the applied process gas is gradually increased. The oxidizing agent is effective to drive the film 210 into a more fully oxidized state, particularly in the deeper portions of the trenches 220. In embodiments described herein, the process gas is a vapor at a pressure between about 5 bar and about 35 bar. However, in other embodiments, other oxidizing agents may be used, such as, but not limited to, ozone, oxygen, peroxides, or hydroxide-containing compounds. When sufficient vapor has been released by the gas panel 150, the isolation valve 155 is closed by the controller 180.

During processing of the substrate 135, the processing region 115, as well as the inlet conduit 157, outlet conduit 161, and conduit 118, are maintained at a temperature and a pressure such that the process gases remain in the vapor phase. The temperature of the processing region 115, as well as the inlet conduit 157, outlet conduit 161, and conduit 118, is maintained at a temperature above the condensation point of the process gas at the applied pressure, but below 250 degrees celsius. The processing region 115, as well as the inlet conduit 157, outlet conduit 161 and conduit 118, is maintained at a pressure below the condensing pressure of the process gas at the applied temperature. The process gas is selected accordingly. In the embodiments described herein, vapor at a pressure between about 5 bar and about 35 bar is an effective process gas when the pressure vessel is maintained at a temperature between about 150 degrees celsius and about 250 degrees celsius. This ensures that the vapor does not condense into water, which could damage the film 210 deposited on the substrate 200.

When the film is observed to have the desired density, processing is complete, as verified by testing the wet etch rate and electrical 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 conduit 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. Then, the power supply to the heaters 140, 119, 158 and 162 is turned off. The door 120 of the pressure vessel 100 is then opened to remove the cassette 130 from the processing region 115. When the substrates 135 are unloaded from the cassette 130, each of the substrates 135 is considered as a semiconductor substrate 200 in fig. 2B. Fig. 2B is a simplified cross-sectional view of a high quality film 210 deposited on a substrate 200. The trenches 230 of the high quality film 210 are void free and thus the film 210 has low porosity and high density.

Fig. 3 is a block diagram of a method of improving the quality of a film deposited on a semiconductor substrate at a temperature below 250 degrees celsius according to one embodiment of the present disclosure. The method 300 begins at block 310 by loading one or more substrates on a cassette into a pressure vessel. In some embodiments, the substrate has a film of silicon oxide, silicon nitride, or silicon oxynitride deposited thereon. In other embodiments, the substrate has a film of metal oxide, metal nitride, or metal oxynitride deposited thereon. In some embodiments, a plurality of substrates may be placed on a cassette and loaded into a pressure vessel. In other embodiments, the cartridge may be omitted.

At block 320, one or more substrates are exposed to a process gas comprising an oxidant at a pressure greater than about 2 bar. In some embodiments, the process gas is an oxidant, including one or more of: ozone, oxygen, water vapor, heavy water, peroxide, hydroxide-containing compounds, isotopes of oxygen (14, 15, 16, 17, 18, etc.) and hydrogen (1, 2, 3), or some combination thereof. The peroxide may be hydrogen peroxide in the gas phase. In some embodiments, the oxidizing agent comprises hydroxide ions, such as, but not limited to, water vapor or heavy water in vapor form. In some embodiments, the one or more substrates are exposed to the vapor at a pressure between about 5 bar and about 35 bar, wherein the pressure is gradually increased from about 5 bar to about 35 bar. In some embodiments, the vapor is introduced at a flow rate of about 500sccm for a period of about 1 minute.

At block 330, the pressure vessel is maintained at a temperature between a condensation point of the process gas and about 250 degrees celsius while exposing the substrate with the film thereon to the process gas. In embodiments using vapor at a pressure between about 5 bar and about 35 bar, the temperature of the pressure vessel is maintained between about 150 degrees celsius and about 250 degrees celsius.

Applying a process gas containing an oxidizing agent at high pressure allows a high concentration of oxidizing species from the process gas to penetrate deeply into the trenches of the film so that the oxidizing species can more thoroughly oxidize the film. The high pressure within the pressure vessel drives the diffusion of the oxidizing species into the deeper trenches where more of the pore region is located. The quality of the resulting processed film can be verified by reducing the wet etch rate of the film by about two-thirds compared to the quality of the film prior to processing. The quality of the treated film can also be verified by testing electrical properties such as breakdown voltage, leakage current, etc. For processes performed at relatively low temperatures below 250 degrees celsius, the improvement in film quality is substantially similar to processes performed at 500 degrees celsius at atmospheric pressure. Furthermore, the time required to complete the high pressure vapor anneal of the film between about 150 degrees celsius and about 250 degrees celsius is about 30 minutes, which makes the process relatively faster than a conventional vapor anneal process performed at 500 degrees celsius at atmospheric pressure.

Applying the treatment gas at high pressure provides advantages over conventional vapor annealing processes at atmospheric pressure. Conventional vapor annealing processes at atmospheric pressure are inadequate due to diffusion of oxidizing species into the membrane and the difference in penetration depth. Conventional vapor annealing processes generally do not drive the oxidizing species deep into the film layer. Accordingly, the disclosure herein advantageously demonstrates an effective method of producing high quality films deposited on semiconductor substrates at temperatures below 250 degrees celsius. By producing high quality films within a thermal budget, the method is capable of creating circuits on the film to fabricate next generation semiconductor devices for desired applications.

While the foregoing is directed to particular embodiments of the present disclosure, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other embodiments may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.