TW466681B - Method for preventing HDP dielectric layer from peeling off - Google Patents

Abstract

The present invention provides a method for preventing high density plasma (HDP) dielectric layer on the silicon nitride layer of a semiconductor chip surface from peeling off. The method comprises first applying inert gas and oxygen into a reaction chamber to be performed with a HDP depositing process; next, using a radio frequency to decompose the inert gas and oxygen into plasma for filling up the reaction chamber; heating the semiconductor chip to increase the temperature for about 20 seconds; then performing a pre-HDP depositing process to form a pre-HDP layer on the surface of the silicon nitride layer; and finally performing a HDP depositing process to form a main HDP layer on the pre-HDP layer.

Description

^ ο 68 1 V. Description of the invention (1) Field of invention 1 The present invention provides a method for avoiding peeling off of the dielectric layer of a high concentration plasma (Chyh density plasma, hdp) on a semiconductor wafer. A method of exfoliating the HDP dielectric layer on a layer. Background: In the semiconductor process, 'in order to have a good isolation between the electronic components on the wafer' to avoid the short circuit phenomenon caused by mutual interference of components, the area oxidation method (1 oca 1 i zed ox i da ti on i so 1 at i on (LOCOS) or shallow trench isolation method for isolation and protection. Because the field oxide layer (Held oxide) produced in the L0c0s process occupies an area of the wafer that is too large, and the generation process is accompanied by the occurrence of the bird, s beak phenomenon, so the minimum line width is 0.2. Below 5 / zm. Semiconductor processes use shallow trench isolation. The shallow trench isolation method is to create a shallow trench (s h a 1 10 w t r e n c h) between components on the surface of the wafer and fill it with an insulating material to produce the effect of electrical isolation. A conventional semiconductor wafer used for making shallow trench isolation (ST I) includes a substrate, a dielectric layer disposed on the substrate ', and a shallow trench disposed in the dielectric layer. A conventional method is to deposit a silicon nitride layer uniformly on the surface of the dielectric layer and in the shallow trench. Then, inert gas is introduced into the chamber for the reaction scheduled for the HDP deposition process.

Page 4 i. Description of the invention (2) Pre-heat step of HDP deposition process. The semiconductor wafer is then heated up for about 5 seconds, and then a methanoxane (siUcane, ^ 0H4m ° and oxygen) is passed to perform a pre-HDP deposition process to form a pre-HDP layer on the surface of the silicon nitride layer Finally, silane (SiH and oxygen) was also passed in to perform an HDP deposition process, which was formed on the front HDp layer-the main 4 HDP dielectric layer (main HDP layer) 'and filled the shallow trench. Because of the silicon nitride dielectric A higher dielectric constant is a good dielectric material, which can ensure the effect of shallow trench isolation and insulation. In addition, a silicon nitride layer filled with shallow trenches before the 0ρ deposition process can also be used as a surname for HDp dielectrics. The etching stop layer (stoop layer). However, the tensile stress of the silicon nitride film (tensiu high | 10 ^, easy to crack (crack) or peel (peeHng); 6-shaped occurrence, and generally The advanced HDp dielectric layer deposited on the silicon-nitrogen layer has a low deposition temperature, so a good-quality silicon-oxygen layer cannot be formed. In addition, it is formed by conventional techniques. The front HDP dielectric layer is similar to a polysilicon layer (silicon rich 〇x if | p, 0 ,, .. ^^. lde, SR0) 'cause the attachment between the front HDP dielectric layer and the nitrogen stone layer to be inferior, see pi 2 +, β > unp person & It is good that the interface often has bubbles, and the protrusion occurs in the second layer, which even causes the nitrogen layer of the dielectric layer to be stripped. ⑥ If the insulation filled with shallow trench isolation is peeled off, it may cause leakage. &, commemorative shirt & come to see right stab bath AI ti @ M t belongs to electricity & from the bottom of the shallow trench, the leakage is 'especially', the line width (1 ine width) is gradually reduced, the shallow trench is isolated The insulating ability of the semiconductor device will affect the overall electrical performance of the semiconductor device. I. Description of the invention (3) Summary of the invention Therefore, the high-concentration plasma (Q1) P on the lambda of the present invention is intended to provide a semiconductor wafer The problem of the conventional technology. The method of exfoliating the dielectric layer is used to solve the problem of the best layer of the present invention-the azolite layer. In the embodiment of the method, the surface of the semiconductor wafer contains a process # β 古 系First, the reverse of a HDP deposition process is scheduled, a pure gas and oxygen are introduced, and then a radio frequency (R F) Dissociating the inert gas and oxygen into a plasma to fill the reaction chamber, and heating and heating the semiconductor wafer for about 20 seconds. Then, a pre-HDP (pre-HDP) deposition process is performed on the silicon-nitrogen layer A front HDP dielectric layer (pre-HDP layer) is formed on the surface. Finally, a HDP deposition process is performed to form a main HDP dielectric layer on the front HDP layer. Since the present invention introduces oxygen during the pre-heating step before the HDP deposition process is performed to form the surface of the semiconductor wafer-a pre-HDP dielectric layer similar to the oxidized oxygen layer structure, thus improving The adhesion ability of the gas stone layer, so there will be no bubble generation or peeling of the HDP dielectric layer ', thereby ensuring the effect of shallow trench isolation and insulation. Detailed description of the invention

Page 6 j S 6 B 1 V. Description of the invention (4) Please refer to Fig. 1 to Fig. 3 'Fig. 1 to Fig. 3 are schematic diagrams of the method for preventing the HDP dielectric layer 24 from peeling off according to the present invention. The h D P dielectric layer 24 produced by the present invention is mainly used as an insulating substance in a shallow trench isolation (STI) process to isolate electrical properties between semiconductor elements (such as MOS transistors). j | | As shown in FIG. 1 ', the semiconductor wafer 10 includes a substrate 12, a dielectric I layer 14 is disposed on the substrate 12, and a silicon nitride layer 20 is disposed on the dielectric layer 14. In the method of the present invention, a photoresist (not shown) is applied on the surface of the nitrogen silicon layer 20, and then a lithography process is performed to define the pattern of the shallow trench 18. A dry etching process is then performed to remove a portion of the nitrogen dream layer 20 and the dielectric layer 14 that are not covered by the photoresist to form a shallow trench 18. The silicon nitride layer 20 remaining on the dielectric layer 14 is used as an etching stop layer in a subsequent etching process. Then, a chemical vapor deposition (CVD) method is used to uniformly deposit a nitrogen fragment layer 16 on the surface of the silicon nitride layer 20 and in the shallow trench μ. As shown in FIG. 2 ', a pre-heat step of an HDP deposition process is then performed to help the subsequent HDP process to be smoother and more uniform. When performing this preheating step, first pass the inert gas (丨 1161 ^ 亘 & 3) and oxygen (〇〇8611) to the reaction chamber ((: 11311 ^ 6] :) scheduled for HDP deposition process. In a preferred embodiment of the invention, argon (argon) is used as a carrier gas to pass in oxygen to make the reaction chamber be rich in oxygen.

Page 7

5. Description of the invention (5) The environment of qi. Then, a radio frequency (RF) frequency is used to dissociate the argon and oxygen gas into a plasma to fill the reaction chamber. The semiconductor wafer is then heated for 10 seconds to a temperature of about 400 ° C to 500 ° C, and then silan (SiH4) a and oxygen are passed in, and a pre-HDP deposition process is performed to form a silicon wafer 16 surface. A front HDp dielectric layer | (py-HDP lyery2. Since the reaction is rushed to form an oxygen-rich environment during this preheating step, a silicon-oxygen layer-like front can be formed during the pre-HDp deposition process. & PP dielectric layer, to improve the adhesion to the nitrogen and silicon layer formed later. Then pass through silane (si H 4) and oxygen to perform an HDP deposition process, forming a main on the front HDP layer 22 A HDP dielectric layer (main HDP layer) 24 and fills the shallow trench 18. As shown in FIG. 3, a planarization process is performed on the semiconductor wafer 10 'using a etch back process or a chemical Chemical mechanical polishing (CMP) is used to remove part of the HDP dielectric layer 24 and the front HDP dielectric layer 22, and complete the production of shallow trench isolation (ST 1) 26. Because of the method 1 of the present invention for making shallow trench isolation The first aspect is to extend the warm-up time to make the reaction After the temperature reached a sufficient 'then the front HDP deposition process; the other hand' the preheating step process of the invention carrying out the HDP deposition process that is performed before the oxygen gas into 'the reaction vessels forming a rich

Page 8 I. Description of the invention (6) i The environment containing oxygen, so that it can be formed during the pre-HDP deposition process | a front H D P dielectric layer similar to the structure of a silicon oxide layer. Compared with the conventional HDP dielectric layer made of polysilicon-silicon-oxide (SRO) layer, the silicon-oxygen layer has better adhesion to the nitrogen-silicon layer, so it does not cause bubbles or peeling of the HDP dielectric layer. Therefore, it can effectively ensure the effect of shallow trench isolation and insulation. i 丨 The above are only the preferred embodiments of the present invention. Any equal changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the patent of the present invention.

Page 9 4 6 6 68 1 Simple description of ffl type Simple illustration of figures Figures 1 to 3 are schematic diagrams of the method for preventing the HDP dielectric layer from peeling off according to the present invention. Explanation of Symbols 10 Semiconductor wafer 12 Substrate 14 Dielectric layer 16 Silicon silicon layer 18 Shallow trench 20 Silicon nitrogen layer 22 Front HDP dielectric layer 24 HDP dielectric layer 26 Shallow trench isolation

Claims (1)

6. Scope of Patent Application 1. A method for avoiding peeling of a high density plasma (H DP) dielectric layer on a semiconductor wafer 'The surface of the semiconductor wafer contains a silicon nitride ( silicon nitride) layer, the method includes: passing inert gas and oxygen into a chamber scheduled for HDP deposition process, and performing a pre-heat step; Do a forehead? (? ^-0?) Deposition process, forming a pre-HDP dielectric layer (pre-HDP layer) on the surface of the silicon nitride layer; and | performing an HDP deposition process, forming a main HDP dielectric on the front HDP layer 丨Electrical layer (mai η HDP 1 ayer). ί I 2. The method according to item 1 of the patent application scope, wherein the front HDP dielectric layer is a silicon oxide layer. 3_ If the method of the scope of patent application is the first item, wherein the former HDP deposition process includes access to a siliconane (SiH4) and oxygen. 4. The method according to item 1 of the patent application range, wherein the preheating step uses a radio frequency (RF) to dissociate the pure gas and oxygen into plasma and fill the reaction chamber to heat the semiconductor. Wafer 0 5. The method according to item 1 of the patent application range, wherein the preheating step is approximately Page 11-! Β 6 π 8 1! '........' VI. Application for Patent Range 20 seconds to heat the semiconductor wafer to about 400 ° C to 500 ° C. 6. The method according to item 1 of the patent application scope, wherein the method is used in a shallow trench isolation (STI) process. 1 7. A method for avoiding peeling off of a high-concentration plasma (HDP) dielectric layer on a semiconductor wafer, the surface of the semiconductor wafer includes a silicon nitrogen layer, the method includes: inert gas and Oxygen (oxygen) is in a reaction chamber scheduled for HDP deposition process, and a radio wave frequency (RF) is used to dissociate the inert gas and oxygen into a plasma to fill the reaction chamber, and the semiconductor wafer is heated and heated for about 20 seconds; performing a pre-HDP deposition process to form a pre-HDP dielectric layer (pre-HDP layer) on the surface of the nitrogen fragmentation layer; and performing an HDP deposition process to form a main HDP dielectric on the pre-HDP layer Layer (mai η HDP 1 ayer). 8. The method according to item 7 of the patent application, wherein the front HDP dielectric layer is a silicon oxide layer. 9. The method of claim 7 in the scope of patent application, wherein the pre-HDP deposition process includes a pass-through of silane (SiH 4) and oxygen. 10. The method according to item 7 of the patent application, wherein the heating step Page 12 ^ + 66 6 b VI. Patent Application Scope The semiconductor wafer is heated to about 4 0 C to 5 0 ° C. 11. The method of claim 7 in the scope of patent application, wherein the method is used in a shallow trench isolation (STI) process. Page 13