| Multi-step anneal of thin films for film densification and improved gap-fill -> Monitor Keywords |
|
|
 
Multi-step anneal of thin films for film densification and improved gap-fillRelated Patent Categories: Electric Heating, Heating DevicesMulti-step anneal of thin films for film densification and improved gap-fill description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070000897, Multi-step anneal of thin films for film densification and improved gap-fill. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60/598,939, filed Aug. 4,2004, entitled "MULTI-STEP ANNEAL OF THIN FILMS FOR FILM DENSIFICATION AND IMPROVED GAP-FILL," the entire contents of which are herein incorporated by this reference. BACKGROUND OF THE INVENTION [0002] As semiconductor device densities continue to get larger and isolation structures between devices continue to get smaller, the challenge of isolating individual devices from one another gets ever more difficult. Improper device isolation is the root cause of a number of device defects, including current leakages that waste power, latch-up that can cause intermittent (and sometimes permanent) damage to circuit functioning, noise margin degradation, voltage shift, and signal crosstalk, to name just some of the problems. [0003] Prior device isolation techniques included local oxidization on silicon (LOCOS) processes that laterally isolated the active device regions on the semiconductor device. LOCOS processes, however, have some well known shortcomings: Lateral oxidization of silicon underneath a silicon nitride mask make the edge of field oxide resemble the shape of a "bird's beak." In addition, lateral diffusion of channel-stop dopants make the dopants encroach into the active device regions, thereby overshrinking the width of the channel region. These and other problems with LOCOS processes were exacerbated as device size continued to shrink with very large scale integration (VLSI) implementation, and new isolation techniques were needed. [0004] Current isolation techniques include shallow trench isolation (STI) processes. Early STI processes typically included etching a trench having a predetermined width and depth into a silicon substrate, filling the trench with a layer of dielectric material (e.g., silicon dioxide), and finally planarizing the dielectric materials by, for example, chemical-mechanical polishing (CMP). For a time, the early STI processes were effective for isolating devices spaced closer together (e.g., 150 nm or more), but as the inter-device space continued to shrink, problems developed. [0005] One of these problems is avoiding the formation of voids and weak seams during the deposition of dielectric material in the trenches. As trench widths continue to shrink, the aspect ratio of trench height to trench width gets higher, and high-aspect ratio trenches (e.g., aspect ratios of about 6:1 or more) are more prone to form voids in the dielectric material due to the premature closure of the trench (e.g., the "bread-loafing" of the dielectric material around the top comers of the trench). The weak seams and voids create uneven regions of dielectric characteristics in trench isolations, which adversely impact the electrical characteristics of the adjacent devices and can even result in device failure. [0006] One technique for avoiding voids is to reduce the deposition rate to a point were the dielectric material evenly fills the trench from the bottom up. While this technique has shown some effectiveness, it slows the overall production time and thereby reduces production efficiency. Thus, there remains a need for device isolation techniques that include the efficient filling of inter-device trenches that also reduce and/or eliminate voids created in the filled trenches. BRIEF SUMMARY OF THE INVENTION [0007] Embodiments of the present invention include a method of annealing a substrate. The substrate may include a trench containing a dielectric material. The method may include the steps of annealing the substrate at a first temperature of about 200.degree. C. to about 800.degree. C. in an oxidizing environment, or ambient. The method may also include annealing the substrate at a second temperature of about 800.degree. C. to about 1400.degree. C. in a second atmosphere lacking oxygen. [0008] Embodiments of the present invention also include a method of annealing a substrate that includes a trench containing a dielectric material. The method includes the step of annealing the substrate at a first temperature of about 400.degree. C. to about 800.degree. C. in the presence of an oxygen containing gas. The method also includes purging the oxygen containing gas away from the substrate, and raising the substrate to a second temperature from about 900.degree. C. to about 1100.degree. C. to further anneal the substrate in an atmosphere that lacks oxygen. [0009] Embodiments of the present invention further include an annealing system. The annealing system includes a housing configured to form an annealing chamber, and a substrate holder configured to hold a substrate within said annealing chamber, where the substrate comprises a trench filled with a dielectric material. The annealing system may further include a gas distribution system configured to introduce gases into said annealing chamber; and a heating system configured to heat the substrate. The gas distribution system introduces a first anneal gas comprising an oxygen containing gas into the chamber while the heating system heats the substrate to a first temperature of about 200.degree. C. to about 800.degree. C. In addition, the heating system heats the substrate to a second temperature of about 800.degree. C. to about 1400.degree. C. in an atmosphere lacking oxygen, after a purge of the oxygen containing gas from the chamber. [0010] Additional features are set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following specification or may be learned by the practice of the invention. The features and advantages of the invention may be realized and attained by means of the instrumentalities, combinations, and methods particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 shows an example of a furnace anneal chamber that may be used with embodiments of the methods of the present invention; [0012] FIG. 2 shows another example of a furnace anneal chamber that may be used with embodiments of the methods of the present invention; [0013] FIG. 3 shows an example of a rapid thermal processing (RTP) system that may be used with embodiments of the methods of the present invention; [0014] FIG. 4 shows an example of a dielectric filled trench formed in a substrate that may be annealed according to embodiments of the method of the present invention; [0015] FIG. 5 plots substrate temperature over a period of time according to embodiments of the method of the present invention; [0016] FIG. 6 shows a flowchart illustrating an example of an annealing method according to embodiments of the present invention; [0017] FIG. 7 shows an electron micrograph of comparative gap-filled shallow trench isolation structures that have been conventionally annealed; and [0018] FIG. 8 shows an electron micrograph of gap-filled shallow trench isolation structures that have been annealed according to an embodiment of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0019] As noted above, the development of voids and weak seams in trench isolations has become an increasing problem as trench widths get smaller (e.g., about 90 nm or less) and trench aspect ratios get higher (e.g., about 6:1 or higher). Embodiments of the present invention include methods of annealing these filled trenches at a lower temperature (e.g., about 200.degree. C. to about 800.degree. C.) in an atmosphere that includes an oxygen containing gas, followed by annealing the trenches at a higher temperature (e.g., about 800.degree. C. to about 1400.degree. C.) in an atmosphere that lacks oxygen. Continue reading about Multi-step anneal of thin films for film densification and improved gap-fill... Full patent description for Multi-step anneal of thin films for film densification and improved gap-fill Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Multi-step anneal of thin films for film densification and improved gap-fill patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Multi-step anneal of thin films for film densification and improved gap-fill or other areas of interest. ### Previous Patent Application: Welding torch device for connection to a welding robot Next Patent Application: Electric heating module Industry Class: Electric heating ### FreshPatents.com Support Thank you for viewing the Multi-step anneal of thin films for film densification and improved gap-fill patent info. IP-related news and info Results in 0.14897 seconds Other interesting Feshpatents.com categories: Accenture , Agouron Pharmaceuticals , Amgen , AT&T , Bausch & Lomb , Callaway Golf 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
