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Apparatus for monitoring a density profile of impuritiesApparatus for monitoring a density profile of impurities description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070222999, Apparatus for monitoring a density profile of impurities. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATION(S) [0001] This is a divisional application based on pending application Ser. No. 10/787,772, filed Feb. 27, 2004, the entire contents of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1 . Field of the Invention [0003] The present invention relates to a method and an apparatus for monitoring a density profile of impurities. More particularly, the present invention relates to a method and an apparatus for monitoring a density profile of boron (B) or phosphorous (P) in an insulating interlayer of the semiconductor substrate. [0004] 2. Description of the Related Art [0005] Technological trends of high integration degree and operation speed of recent semiconductor devices render intervals between various patterns in a memory cell shorter, so that a space between gate electrodes becomes narrower and a conductive pattern forming a gate electrode becomes higher. [0006] Therefore, coating an insulating interlayer to planarize a substrate surface frequently causes a void defect between two adjacent gate electrodes. [0007] A borophosphorous silicate glass (hereinafter, referred to as BPSG) is now widely used as an insulating interlayer to prevent a void defect since BPSG has good fluidity and step coverage. The BPSG includes small doses of boron (B) and phosphorous (P) in a silicon oxide (SiO.sub.2) layer, and is generally deposited on a substrate surface through an atmospheric pressure chemical vapor deposition (APCVD) process. Accordingly, an operation characteristic of a BPSG layer is decisively influenced by the density of boron (B) and phosphorous (P). More specifically, the density profile of the boron (B) and phosphorous (P) distributed along a depth of a cross sectional surface of a BPSG layer (hereinafter, referred to as "depth profile") has more effect on operation characteristics of the BPSG layer than does the bulk density of the boron (B) and phosphorous (P). [0008] When relatively small quantities of the boron (B) and phosphorous (P) in a lower portion of the BPSG layer are used, a void defect is more frequently generated and a static refresh rate is considerably reduced during a self-aligned contact process. In addition, an etching rate is strongly influenced by the densities of the boron (B) and phosphorous (P) Therefore, the cross sectional surface of the BPSG layer becomes non-uniform in accordance with the density profiles of the boron (B) and phosphorous (P). [0009] In general, the density profile of boron (B) or phosphorous (P) has been measured by a secondary ion mass spectrometry (SIMS) method or a glow discharge luminescence spectrometry (GDLS) method. However, the SIMS and GDLS methods are carried out after destruction of the BPSG layer. Furthermore, a density analysis method using a Fourier transform infra-red (FT-IR) apparatus indicates the bulk density of boron (B) and phosphorous (P), but does not indicate any information regarding density variation along a thickness of the BPSG layer. [0010] Therefore, there is a need for an improved density analysis method for analyzing a depth profile of boron (B) and phosphorous (P) in real time during the process without destructing the substrate. SUMMARY OF THE INVENTION [0011] Accordingly, the present invention is directed to a method of monitoring a depth profile of impurity densities in a pattern of a semiconductor substrate without destruction of the substrate during the process. Furthermore, the present invention is directed to an apparatus for monitoring a depth profile of impurity densities in a pattern of a semiconductor substrate without destruction of the substrate during the process. [0012] Therefore, it is a feature of an embodiment of the present invention to provide a method of monitoring a density profile of impurities, the method including presetting a monitoring position of a thin layer coated on a substrate, the density profile of impurities being monitored from the monitoring position in a direction of thickness of the thin layer, moving an exposer for exposing a local area of the thin layer to the monitoring position, exposing the local area of the thin layer along the direction of thickness of the thin layer, forming a shape profile of the exposed local area of the thin layer, and monitoring the density profile of impurities by determining a density of impurities in accordance with the shape profile. [0013] The thin layer preferably includes an insulating interlayer coated on a semiconductor substrate. [0014] The insulating interlayer preferably includes a borophosphorous silicate glass (BPSG) layer. [0015] Exposing the local area of the thin layer along the direction of thickness of the thin layer may include a wet etching process. [0016] The wet etching process may be carried out using a buffer oxide etchant (BOE). [0017] Forming the shape profile may include irradiating a light onto the exposed local area of the thin layer, detecting an intensity of light reflected from the exposed local area of the thin layer, and comparing the intensity of the light reflected from adjacent reflecting points of the exposed local area. [0018] Forming the shape profile may further may include transforming the shape profile into an image. [0019] Transforming the shape profile into an image may include using a solid state imaging device. [0020] Therefore, it is another feature of an embodiment of the present invention to provide an apparatus for monitoring a density profile of impurities, the apparatus including a stage on which a substrate is disposed, a thin layer including a plurality of impurities being coated on the substrate, an exposer that exposes a local area of the thin layer along a direction of thickness of the thin layer, a shape profile generator that generates a shape profile of the exposed local area of the thin layer, a density profile generator that generates a density profile of impurities by determining a density of the impurities corresponding to the shape profile, and a controller that controls the exposer, the shape profile generator, and the density profile generator by using a preset monitoring position of the thin layer, the density profile of impurities being monitored from the preset monitoring position in the direction of thickness of the thin layer. [0021] The exposer preferably includes a container for containing an exposing material and a nozzle for injecting the exposing material into the local area of the thin layer. Continue reading about Apparatus for monitoring a density profile of impurities... Full patent description for Apparatus for monitoring a density profile of impurities Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Apparatus for monitoring a density profile of impurities 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. 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