KR100634153B1 - Method for detecting oxidation induced stacking fault of a semiconductor device - Google Patents

Abstract

The present invention relates to an OISF detection method of a semiconductor device, wherein the OISF detection method removes an oxide film formed on a wafer after heat treatment of a wafer on which a pattern is not formed. Dip the wafer into SECCO etchant to expose the OISF and check the OISF through the dark hood. In addition, the wafer on which the multilayer film for pattern formation is formed is etched after the heat treatment using an LAL. Next, the conductive film formed on the wafer is etched and analyzed for OISF using KLA. The wafer is immersed in SECCO etchant and analyzed for OISF defects through a dark hood. As such, the operator can confirm this directly by exposing the OISF latent on the wafer to the surface.

Description

METHOOD FOR DETECTING OXIDATION INDUCED STACKING FAULT OF A SEMICONDUCTOR DEVICE}

1 is a flowchart sequentially showing a method for detecting an OISF of a bare wafer according to the present invention;

2 is a flowchart sequentially showing an OISF detection method of a patterned wafer according to the present invention;

3a to 3c show the results of analyzing the OISF exposed on the wafer using the KLA facility; And

4 is a view showing the number of OISF detected according to the analysis method according to the present invention.

The present invention relates to a semiconductor device, and more particularly to a method for detecting OISF of a semiconductor device.

As semiconductor memory devices are highly integrated, wafer design rules are becoming smaller. Therefore, device isolation methods are also changing. As shown in the table below, as design rules become smaller, it has shifted from LOCOS and sepoly oxide (SEPOX) isolation methods to poly spacer LOCOS and trench isolation methods. As the design rule becomes smaller and smaller, stress is increased to generate an oxidation induced stacking fault (OISF). The OISF is more easily generated at higher oxygen concentrations and at higher temperatures.

OISF generated in the state of high oxygen concentration increases to the temperature, and AOP (abnormal oxyen precipitation) acts as a nucleation site and appears as line OISF or point OISF. As described above, defects generated by OISF acting as a nucleus do not appear on the wafer surface and cannot be visually confirmed.

In addition, OISF is generated when stress increases due to mutual organic relation with device isolation structure in PSL structure. OISF generated by the PSL structure is also not exposed on the wafer surface, which makes it difficult to analyze.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a method for analyzing an OISF that is latent on a wafer and does not appear on the surface.

According to a feature of the present invention for achieving the object of the present invention as described above, the OISF analysis method provides a wafer without a pattern formed. The wafer is heat treated at 1150 ° C. for 10 hours. The oxide film formed on the wafer is removed. The wafer is immersed in SECCO etchant to expose the OISF. Light is irradiated onto the wafer to identify the OISF as the contrast of the wafer surface. And microscopically confirm the exposed OISF.

According to another feature of the invention, the OISF analysis method provides a wafer in which a pattern is formed by etching the multilayer film of the oxide film and the nitride film. The wafer is heat treated at 1150 ° C. for 10 hours. The oxide film and nitride film formed on the wafer are etched. The oxide film is etched using LAL-BOE. The conductive film formed on the wafer is etched to expose the OISF to the wafer surface. The exposed OISF is analyzed using a particle measuring device (KLA-Tencor). After immersing the wafer in SECCO etchant, the wafer is illuminated with light to analyze OISF defects. And microscopically analyze the OISF defects on the substrate.
Here, LAL-BOE is an oxide film etching chemical (NH4F + HF mixed solution) of BOE (Buffered Oxide Etchant-buffered oxide etching) series, and is commonly referred to as LAL-BOE. Silicon Etchant).

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4.

Referring to FIGS. 1 and 2, in the novel OISF detection method of the present invention, after a wafer is heat-treated at a high temperature, a wafer having no pattern is analyzed after etching with a Seco (SECCO) etchant and a wafer having a pattern formed thereon After etching using the LAL-BOE solution, the OISF expressed on the wafer is analyzed using a particle measuring apparatus.

1 is a flowchart sequentially illustrating a method of analyzing an OISF latent in a bare wafer.

Referring to FIG. 1, an oxide film is formed by heat treating a wafer without a pattern at 1150 ° C. for 10 hours (12). The oxide layer is removed through a strip process, and the wafer is exposed to SECCO etchant to partially etch the silicon substrate (16). In this case, the wafer is exposed to SECCO etchant for 30 minutes. As a result, latent OISF is exposed to the surface. The exposed OISF is detected through an analysis operation through a dark hood that irradiates light on the wafer. Finally, the OISF is checked through the microscope.

As described above, the wafer in which the pattern is not formed exposes the latent OIS to the surface by removing the oxide film and etching the silicon substrate.

2 is a flowchart sequentially illustrating a method of analyzing an OISF latent on a patterned wafer.

Referring to FIG. 2, a process for forming a pattern on a substrate of a semiconductor memory device (after deposition of a pad oxide film and an insulating film (52) and a photo process is performed to form an active region (54), followed by deposition of a conductive film (56) on the spacer) The wafer on which the process (58) is formed) is heat-treated at 1100 ° C. for 10 hours to form an oxide film (60 ', an oxide film is formed at the same time as the field oxidation process is performed). The wafer is etched 1 μm for 20 minutes through the LAL-BOE etchant (64). The conductive film is then etched to expose the OISF to the wafer surface (66). Next, the OISF is checked using a particle measuring apparatus (68). The OISF analysis result using the particle measuring device is shown in FIGS. 3A to 3C. OISF appears in the form of a ring on the wafer surface, Figure 3a is a case of a lot of OISF throughout the wafer, Figure 3b is an OISF appears in the form of an inner ring of the wafer. If there is no OISF at all, it does not appear in any form on the wafer surface as shown in FIG. 3C.

The table below shows OISF detection results for bare wafers and unpatterned wafers.

Active pattern + OISF recipe after B / S Bare (OISF recipe) vendor laser mark Dv.D2 OISF by KLA AOP-size AOP Dia Dv.D2 AOP-size AOP Dia vendor OISF by D / H Dv.D2 AOP-size AOP Dia A # O1 8.8 U 0.7 13.2 10.5 radish radish SEH SWI radish 9.2 radish radish # 02 8.8 0.9 13.3 8.3 B # O3 7.85 1.5 16.1 11.9 SITIX 8.3 # O4 7.9 1.7 14.4 8.05 C # O5 10.85 0.7 13.2 11.7 MSILPI 9.9 # O6 11.45 1.2 13.1 11.85 D # O7 12 1.1 16.6 14.25 SILTRON 10.2 # O8 13.8 0.9 18.7 12.2 E # O9 7.1 1.7 10.4 9.45 PHC HPS 7.95 0.2 12 # 1O 7.6 2.0 10.1 9.2 0.2 11.8 F # 11 13.3 1.5 15.9 15.2 PHC 10.85 # 12 13.4 1.3 15.7 13.1 G # 13 10.45 1.3 12.6 10.4 PHC 9.15 # 14 8.4 1.0 12.2 11 H # 15 10.55 1.1 15.4 12.4 SILTRON 9.1 # 16 10.96 1.2 15.2 9.2

Where Dv.D2 is the diameter of the OISF ring (cm) appearing on the wafer, AOP-size is the size of the AOP (μm), and AOP Dia represents the AOP length (cm) around the ring.

After OISF analysis using the particle measuring device, the wafer is exposed to SECO (etch liquid) for 30 minutes (70), and the OISF on the wafer is analyzed through a dark hood that irradiates the wafer (72). Finally, the wafer is analyzed through a microscope (74). According to the above analysis method, it is possible to confirm the number of OISF exposed on the wafer as shown in FIG.

According to the present invention as described above, through the heat treatment to form an oxide film on the wafer and the etching process by the LAL-BOE solution and SECCO etching solution to expose the potential OISF on the wafer surface to confirm the distribution and number of OISF It can be effective.

Claims (3)

delete Providing a wafer on which a multilayer film of a first oxide film, a nitride film, and a conductive film is formed; Heat treating the wafer to form a second oxide film; Etching the second oxide layer using a buffer oxidation etching (BOE) solution; Etching the conductive film formed on the wafer to expose the OISF to the wafer surface; Identifying the OISF using a particle measuring device; Dipping the wafer into SECCO etchant; Irradiating light on the wafer to identify OISF; OISF detection method comprising the step of identifying the OISF on the wafer with a micro microscope. The method of claim 2, Heat treatment of the wafer is performed at 1100 ° C. for 10 hours; Exposing the wafer to a SECCO etchant for 30 minutes.

Images