經濟部中央標隼局員工消費合作社印製 A7 B7 '五、發明説明（】） 詳細說明： 1. 發明之技術領域： 本發明是關於一種在積體電路中形成低粒子數氧化矽 層的方法。 2. 發明背景： 在積體電路的製程中，二氧化矽薄膜是最重要的介電 材料。為了降低反應所需的溫度，以達到減低製程熱預算 (Thermal Budget)的目的，電漿加強式化學氣相沉積法 (PECVD)已成為主要的薄膜沉積技術之—。目前科技界及業 界已發展出多種化學反應機制，可利用電漿加強式化學氣 相沉積法在晶片表面形成二氧化矽薄膜，其中以SiH4和NzO 做為反應氣體的技術是其中很重要的一種。 傳統技術在以SiHdDN2〇做為反應氣體，利用電漿加強 式化學氣相沉積法形成二氧化矽薄膜時，係先進行穩定化 ‘步驟。待SiH4和N2〇等反應氣體的流量趨於穩定之後，再將 電漿產生器的電源開啓，進行二氧化矽薄膜的沉積。該穩 定化步驟係將SiH4°N2〇兩種反應氣體的閥門同時開啓，由 於反應過程中所需SiH4的量較少，所以Sim將迅速達到飽 和，但N2O則大約5抄之後才會達到飽和。因此在進行穩定化 步驟的初期，SiH4已達到飽和，而M)則尚未達到飽和，此 時SiH4/N2〇的比値遠大於其在正式沉積步驟時的比値。因為 SiH4過大的分崔，使得SiH4會提早在晶片表面沈積而產生大 量不規則的粒子（每單位面積所生成直徑大於0.2微米的粒 子個數超過20000個），嚴重影響產品的良率和穩定性。 2 本紙張尺度適用中國國家標3L . CNS ; A4«L格ί+ ：!丨0+X297公楚 ~ ~ |_^--------1------1Τ------^ (誚先閱讀背面之注意事項再填寫本頁) 經濟部中央標聿局員工消費合作社印製 A7 B7五、發明説明（上） J3.11:明之簡要說明： 本發明之主要目的是提供一種在積趙電路中形成低粒 子數氧化移增的方法。 本發明之次要目的是提供—種在積體電路中形成優良 氧化矽層的方法。 本發明係利用下列製程步驟’以達到上述目的：首先 在進行穩定化步驟之前’先以氧化二菌·Ν2〇、氣氣N2或其混 合氣體進行預流（Pre-flow)步驟。接著進行穩定化步驟’ 將反應氣體SiH4和N2〇通入電漿加強式化學氣相沉積室，但 不開啓電娘產生器的電源。最後進行沉積步驟，將反應氣 體SiH4和N2〇離子繼續通入該化學氣相沉積室*並開啓電漿 產生器的電源，此時SiHi和N2O會在晶片表面反應而生成二 氧化矽Si〇2，並沉積在晶片表面以形成二氧化矽薄膜。 本發明在進行穩定化步驟之前先以N2〇、N2或其混合氣 體進行預流步驟，所形成的二氧化矽薄膜，其每單位面積 所生成直徑大於0. 2微米的粒子個數在30個以下，遠小於習 知製程所生成二氧化矽薄膜的粒子個數。這不僅獲得較佳 的平坦度，並使得所形成二氧化矽薄膜的應力結構更加優 良。本發明所述在積體電路中形成低粒子數氧化矽層的方 法於焉完成。 4. 圖式說明： 圖一為本發明中形成二氧化矽薄膜的製程剖面示意圖。 5. 圖號說明： 10-晶片 20-二氧化矽薄膜 3 太紙張尺度適用Ag國家標準、C-NS； :, .Μ故格（2Ki y 2<Γ公犮：； (讀先閱讀背面之注意事項填寫本頁) -裝 、-0 經漭部中央標準局員工消費合作社印繁 A7 B7 五、發明説明（i) 第一實施例A7 B7 printed by the Consumers 'Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs' 5. Description of the invention ()] Detailed description: 1. Technical Field of the Invention: The present invention relates to a method for forming a low-particle-count silicon oxide layer in an integrated circuit . 2. Background of the Invention: Silicon dioxide films are the most important dielectric materials in the fabrication of integrated circuits. In order to reduce the temperature required for the reaction, in order to reduce the thermal budget of the process, plasma enhanced chemical vapor deposition (PECVD) has become one of the main thin film deposition technologies—. At present, a variety of chemical reaction mechanisms have been developed in the scientific and technological circles and the industry. Plasma enhanced chemical vapor deposition can be used to form a silicon dioxide film on the wafer surface. Among them, the technology using SiH4 and NzO as reaction gases is an important one. . In the conventional technique, when SiHdDN20 is used as a reaction gas and a plasma enhanced chemical vapor deposition method is used to form a silicon dioxide film, the stabilization step is performed first. After the flow of the reaction gases such as SiH4 and N20 has stabilized, the power of the plasma generator is turned on to deposit the silicon dioxide film. In the stabilization step, the valves of the two reaction gases of SiH4 ° N2O are opened at the same time. Since the amount of SiH4 required during the reaction is small, Sim will quickly reach saturation, but N2O will reach saturation after about 5 cycles. Therefore, at the beginning of the stabilization step, SiH4 has reached saturation, and M) has not yet reached saturation. At this time, the ratio of SiH4 / N2O is much larger than that during the formal deposition step. Because SiH4 is too large, SiH4 will be deposited on the wafer surface early and generate a large number of irregular particles (the number of particles with a diameter greater than 0.2 microns per unit area exceeds 20,000), which seriously affects the yield and stability of the product. . 2 This paper size applies to Chinese national standard 3L. CNS; A4 «L 格 ί + :! 丨 0 + X297 公 楚 ~ ~ | _ ^ -------- 1 ------ 1Τ --- --- ^ (诮 Please read the notes on the back before filling this page) Printed by the Consumers Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs A7 B7 V. Description of the Invention (Part I) J3.11: Brief Description of the Main Purpose of the Invention: It is to provide a method for forming low particle number oxidation shift in the product circuit. A secondary object of the present invention is to provide a method for forming an excellent silicon oxide layer in an integrated circuit. In the present invention, the following process steps are used to achieve the above-mentioned purpose: First, before the stabilization step is performed, a pre-flow step is performed with dioxidizing bacteria · N20, gas N2 or a mixed gas thereof. Next, a stabilizing step is performed. The reaction gases SiH4 and N20 are passed into a plasma enhanced chemical vapor deposition chamber, but the power of the generator is not turned on. Finally, a deposition step is performed, and the reaction gases SiH4 and N2O ions are continuously passed into the chemical vapor deposition chamber * and the power of the plasma generator is turned on. At this time, SiHi and N2O will react on the wafer surface to form silicon dioxide SiO2. And deposited on the surface of the wafer to form a silicon dioxide film. The present invention performs a pre-flow step with N2O, N2 or a mixed gas thereof before performing the stabilization step. The silicon dioxide film formed has a number of particles having a diameter greater than 0.2 micrometers per unit area in 30 Below, it is much smaller than the number of particles of the silicon dioxide film produced by the conventional process. This not only obtains better flatness, but also makes the stress structure of the formed silicon dioxide film more excellent. The method for forming a low-particle-count silicon oxide layer in an integrated circuit according to the present invention is completed in a single step. 4. Schematic description: FIG. 1 is a schematic cross-sectional view of a process for forming a silicon dioxide film in the present invention. 5. Description of drawing number: 10-chip 20-silicon dioxide film 3 Too large paper size Applicable to Ag national standard, C-NS;:, .Μ 故 格 (2Ki y 2 < Γ 公 犮:; (Read the first read on the back Note for filling in this page) -Equipment, -0 Employees' Cooperatives of the Central Bureau of Standards of the People's Republic of China, India and India A7 B7 V. Description of the invention (i) First embodiment
此步驟為本實施例重點，在進行穩定化 ($士&1^112&1^〇11)步驟之前，先以氧化二氮仏0氣體進行預流 (Pre-flow)步驟。所述預流步驟的實施時間應大於〇· 1抄D 接著進行穩定化步驟’將反應氣體SiHi和N2〇通入電聚 加強式化學氣相沉積室，但不開啓電漿產生器的電源。進 行此步驟的目的，係因反應氣體SiH4和M)在剛通入該化學 氣相说積室的初期流里極為不穩，因此在開啓電欺產生器 電源之前，先進行此一穩定化步驟°待反應氣體的流量穩 定之後再開啓電嚴產生器的電源，以精確地控制薄膜況積 的速率與品質。 最後以電漿加強式化學氣相沉積法（PECVD)進行沉積步 驟，將反應氣體SiH4和N2O離子繼續通入該化學氣相沉積 室，並開啓電漿產生器的電源，此時Siil4°N2〇離子會在晶 片表而反應而生成二氧化eSi〇2 *並沉積在晶片10表面以形 成二氧化取薄膜20，如圖—所示。 本實施例在進行穩定化步驟之前先以N2O氣體進行預流 步驟，所形成的二氧化矽薄膜，其每單位面積所生成直徑 大於0.2微米的粒子個數在別個以下，遠小於習知製程所生 成二氧化矽薄膜的粒子個數。這不僅獲得較佳的平坦度， 並使得所形成二氧化矽薄膜的應力結構更加優良。本發明 所述在積體電路中形成低粒子數氧化矽層的方法於焉完 成0 4 本紙張汶度逮用中國困家標纸' CNS +; A4C格（210X297公釐i 1Μ------II------IT------4 (讀先閱讀背面之注意事項再填寫本I ) A7 ______B7 五、發明説明（4) « 在傳統製程中，將晶片送進離子加強式化學氣相沉積 室以後直接進行穩定化步驟，此步驟將SiH4和N2〇兩種反應 氣體的閥門同時開啓。因為反應過程中所需SiH4的量較少， 因此SiH4較早達到飽和。因此在進行穩定化步驟的初期大約 5秋的時間裡，Sift已達到飽和，而N2O則尚未達到飽和，此 時SiH4/N2〇的比値遠大於其在正式沉積步驟時的比値。因為 SiH4過大的分壓，使得Sim會提早在晶片表面沉積而產生不 規則的粒子，嚴重影響產品的良率和穩定性。本實施例在 進行穩定化步驟之前先以氣體進行預流步驟，其目的便 在於讓N2〇的閥門提早開啟，以便讓N2〇較Sil^早達到飽和， 如此SiH4的分壓便不會太高，不會在晶片表面沉積而產生大 量形狀不規則的粒子。 第二實施例 此步驟為本實施例重點，在進行穩定化 (Stabilization)步驟之前，先以氮氣N2進行預流（Pre-flow) 步驟。所述預流步驟的實施時間應大於0.1秒。 經濟部中央標準局員工消贄合作社印裝 I - - I n - - I -(i^—----I 丁 0¾-4 tr (讀先閱讀背面之注意事項再填苟本頁) 接著進行穩定化步驟，將反應氣體SiH4和犯0通入電嚴 加強式化學氣相沉積室，但不開啓電漿產生器的電源°進 行此步驟的目的，係因反應氣體SiH4和N2O在剛通入該化學 氣相沉積室的初期流量極為不穩，因此在開啓電漿產生器 電源之前，先進行此—穩定化步驟。待反應氣體的流量穩 定之後再開啓電漿產生器的電源，以精確地控制薄膜沉積 的速率與品質。 5 本紙張尺度適用中國國家標痒（CNTS ϊ Λ4規格（2丨0><'297公釐； B7 趑濟部中央標隼局貝二消費合作.社印^ 五、發明説明（5" ) · 最後以電殿加強式化學氣相沉積法（PECVD)進行況積步 驟，將反應氣體SiH4和NzO離子繼續通入該化學氣相況積 室，並開啓電娘產生器的電源，此時SiH4和仏0離子會在晶 片表面反應而生成二氧化eSi〇2，並沉積在基板10表面以形 成二氧化ί夕薄膜20 *如圖—所示。 本實施例在進行穩定化步驟之前先以Ν2氣體進行預流步 驟，所形成的二氧化矽薄膜*其每單位面積所生成直徑大 於0. 2微米的粒子個數在30個以下，遠小於習知製程所生成 二氧化矽薄膜的粒子個數。這不僅獲得較佳的平坦度，並 使得所形成二氧化矽薄膜的應力結構更加優良。本發明所 述在積體電路中形成低粒子數氧化矽層的方法於焉完成。 在傳統製程中，將晶片送進電漿加強式化學氣相沉積 室以後直接進行穩定化步驟，此步驟將SiH4和Ν2〇兩種反應 氣體的閥門同時開啟。因為反應過程中所需SiH4的量較少， 因此SiH4較早達到飽和。因此在進行穩定化步驟的初期大約 5秒的時間裡，SiH4已達到飽和，而N2〇則尚未達到飽和，此 時SiH4/N2〇的比値遠大於其在正式沉積步驟時的比値。因為 SiH4過大的分崔，使得SiH4會提早在晶片表面沈積而產生不 規則的粒子，嚴重影響產品的良率和穩定性。本實施例在 進行穩定化步驟之前先以N2氣體進行預流步驟，其目的便在 於減少SiH4的分崔，SiH4便不會在晶片表面沈積而產生不規 則的粒子。 第三實施例 6 本坻G度適$中11£家標（CNS ) A規格ί 2ίϋ、. 29-公龙' ' --------1¾------IT------.^ V (諳先閲讀背面之注意事項再填寫本頁) 經濟部中央標準局員工消費合作社印策 A7 _B7^____五、發明説明（έ) 此步驟為本實施例重點，在進行穩定化 (Stabilization)步驟之前，先以氧化二氮犯〇和龜氣仏的温 合氣體進行預流（Pre-flow)步驟。所述預流步驟的實施時 間應大於(U秒。 接著進行穩定化步驟，將反應氣體SiH4和M)通入電欺 加強式化學氣相沉積室，但不開啓電漿產生器的電源。進 行此步驟的目的，係因反應氣體SiH4和犯0在剛通入該化學 氣相沉積室的初期流量極為不穩，园此在開啓電漿產生器 電源之前，先進行此一穩定化步驟。待反應氣體的流量穩 定之後再開啓電漿產生器的電源，以精確地控制薄膜沉積 的速率與品質。 最後以電漿加強式化學氣相沉積法（PECVD)進行沉積步 驟，將反應氣體SiH4和N2〇離子繼續通入該化學氣相沉積 室，並開啓電漿產生器的電源，此時SiH4和N2O離子會在晶 片表面反應而生成二氧化矽Si〇2，並沉積在基板10表面以形 成二氧化矽薄膜20，如圖一所示。 本實施例在進行穩定化步驟之前先以氧化二氮N2〇和氮 氣N2的混合氣體進行預流步驟，所形成的二氧化矽薄膜，其 每單位面積所生成直徑大於0. 2微米的粒子個數在30個以 下，遠小於習知製程所生成二氧化矽薄膜的粒子個數。這 不僅獲得較佳的平坦度，並使得所形成二氧化矽薄膜的應 力結構更加優良。本發明所述在積體電路中形成低粒子數 氧化矽層的方法於焉完成。 7 1^-------1¾水------1T------^ (讀先閱讀背面之注意事項再填寫本頁) 本紙張尸、度適用中國國家標準（CNS : A4規格· 210x29?公窀） B8^v63 B7 一 II ιτ — 五、發明説明（γ) 在傳統製程中，將晶片送進電漿加強式化學氣相沉積 室以後直接進行穩定化步驟，此步驟將SiH4和阶0兩種反應 氣體的閥門同時開啓。因為反應過程中所需SiH4的量較少， 因此SiH4較早達到飽和。因此在進行穩定化步驟的初期大約 5秒的時間裡9 SiH4已達到飽和，而N2〇則尚未達到飽和*此 時SiH4/N2〇的比値遠大於其在正式沉積步驟時的比値。因為 SiH4過大的分壓，使得SiH4會提早在晶片表面沉積而產生不 規則的粒子，嚴重影響產品的良率和穩定性。本實施例在 進行穩定化步驟之前先以氧化二氮N2〇和氮氣沁的混合氣體 進行預流步驟，其目的便在於減少SiH4的分壓，SiH4便不會 在晶片表面沉積而產生不規則的粒子。 本發明係透過三具體實施例加以敘述，說明本發明的 原則和精神，應可瞭解本發明並不侷限於所揭露的具體資 施例，因此，在本發明之原則和範圍底下所作任何相關細 節上之變化，都應視為本發明的進一步實施例。 I-Μ-------私衣------，ar------^ (誚先閱讀背面之注意事項再填寫本頁) 經濟部中央標準局員工消費合作社印製 8 木纸張尸、度遠用中國國家標準（CNS Λ4規輅i 公左This step is the focus of this embodiment. Before performing the stabilization ($ 1,112,1,101) step, a pre-flow step is performed with dioxinium oxide gas. The implementation time of the pre-flow step should be greater than 0.1 · D, and then a stabilization step 'is performed, in which the reaction gases SiHi and N20 are passed into the electropolymerization enhanced chemical vapor deposition chamber, but the power of the plasma generator is not turned on. The purpose of this step is because the reaction gases SiH4 and M) are extremely unstable in the initial flow just after entering the chemical vapor storage chamber. Therefore, this stabilizing step is performed before turning on the power of the electric generator. ° After the flow of the reaction gas is stable, turn on the power of the electric generator to precisely control the rate and quality of the thin film accumulation. Finally, plasma deposition enhanced chemical vapor deposition (PECVD) is used to perform the deposition step. The reaction gases SiH4 and N2O ions are continuously passed into the chemical vapor deposition chamber, and the power of the plasma generator is turned on. At this time, Siil4 ° N2. The ions will react on the wafer surface to form the dioxide eSi0 2 * and deposited on the surface of the wafer 10 to form a thin film 20 for the extraction of oxygen, as shown in FIG. In this embodiment, the pre-flow step is performed with N2O gas before the stabilization step. The number of particles with a diameter larger than 0.2 micrometers per unit area of the formed silicon dioxide film is less than others, which is far less than that of the conventional manufacturing process. The number of particles forming a silicon dioxide film. This not only obtains better flatness, but also makes the stress structure of the formed silicon dioxide film more excellent. The method for forming a low-particle-count silicon oxide layer in an integrated circuit according to the present invention is completed in 0 4 of this paper. The paper is made of Chinese paper, CNS +; A4C grid (210X297 mmi 1M ---- --II ------ IT ------ 4 (Read the precautions on the back before filling in this I) A7 ______B7 V. Description of the invention (4) «In the traditional process, send the wafer into the ion In the enhanced chemical vapor deposition chamber, the stabilization step is performed directly afterwards. This step simultaneously opens the valves of the two reaction gases, SiH4 and N2O. Because the amount of SiH4 required during the reaction is small, SiH4 reaches saturation earlier. Therefore In the early stage of the stabilization step, about five autumns, Sift has reached saturation, while N2O has not yet reached saturation. At this time, the ratio of SiH4 / N2〇 is much larger than that during the formal deposition step. Because SiH4 is too large The partial pressure of Sim makes the deposition on the wafer surface earlier and produces irregular particles, which seriously affects the yield and stability of the product. In this embodiment, the pre-flow step is performed with a gas before the stabilization step. The purpose is to Let N2〇 valve open early so that N2〇 reaches saturation earlier than Sil ^, so the partial pressure of SiH4 will not be too high, and it will not deposit a large number of irregularly shaped particles on the surface of the wafer. Second Embodiment This step is the focus of this embodiment and is stable. Before the stabilization step, the pre-flow step is performed with nitrogen N2. The implementation time of the pre-flow step should be greater than 0.1 seconds. The staff of the Central Standards Bureau of the Ministry of Economic Affairs has printed out the cooperatives I--I n --I-(i ^ —---- I 丁 0¾-4 tr (Read the precautions on the back before filling this page) Then proceed to the stabilization step, and pass the reaction gas SiH4 and guilty 0 into the electricity-enhanced type The chemical vapor deposition chamber, but the power of the plasma generator is not turned on. The purpose of this step is because the initial flow of the reaction gases SiH4 and N2O into the chemical vapor deposition chamber was extremely unstable, so the power was turned on. Before the power supply of the pulp generator, first perform this-stabilizing step. After the flow of the reaction gas is stabilized, turn on the power of the plasma generator to precisely control the rate and quality of film deposition. 5 This paper scale is applicable to the Chinese national standard itch (CNTS Λ4 specifications (2 丨 0 > < '297 mm; B7, Ministry of Economic Affairs, Central Bureau of Standards, Bayer Consumer Cooperation. Press printed by the company ^ V. Description of the invention (5 ") (PECVD) Perform the deposition step, continue to pass the reaction gases SiH4 and NzO ions into the chemical vapor deposition chamber, and turn on the power of the generator. At this time, SiH4 and 仏 0 ions will react on the wafer surface to form two ESi02 is oxidized and deposited on the surface of the substrate 10 to form a thin film 20 of silicon dioxide, as shown in FIG. In this embodiment, before performing the stabilizing step, a pre-flow step is performed with N2 gas. The formed silicon dioxide film * has a number of particles with a diameter greater than 0.2 micrometers per unit area. The number of particles is less than 30, which is far less than the conventional one. Know the number of particles in the silicon dioxide film produced by the manufacturing process. This not only obtains better flatness, but also makes the stress structure of the formed silicon dioxide film more excellent. The method for forming a low-particle-count silicon oxide layer in an integrated circuit according to the present invention is completed. In the traditional process, the wafer is sent to a plasma enhanced chemical vapor deposition chamber and then the stabilization step is performed directly. This step simultaneously opens the valves of the two reaction gases, SiH4 and N20. Because the amount of SiH4 required during the reaction is small, SiH4 reaches saturation earlier. Therefore, in the initial stage of the stabilization step, about 5 seconds, SiH4 has reached saturation, while N2O has not yet reached saturation. At this time, the ratio of SiH4 / N2O is much larger than that during the formal deposition step. Because SiH4 is too large, SiH4 will be deposited on the wafer surface early and produce irregular particles, which will seriously affect the yield and stability of the product. In this embodiment, the pre-flow step is performed with N2 gas before the stabilization step. The purpose is to reduce the fraction of SiH4. SiH4 will not be deposited on the wafer surface and irregular particles will be generated. Third Embodiment 6 This book is suitable for a family of 11 pounds (CNS) A specifications ί 2ί,. 29-Gonglong '' -------- 1¾ ------ IT --- ---. ^ V (谙 Please read the precautions on the back before filling this page) Imprint A7 _B7 ^ ____ by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs V. Description of the Invention This step is the focus of this embodiment. Before performing the stabilization step, a pre-flow step is performed with a warm gas that is a mixture of nitrous oxide and turtle gas. The implementation time of the pre-flow step should be greater than (U seconds.) A stabilization step is then performed, and the reaction gases SiH4 and M are passed into the electroenhanced chemical vapor deposition chamber without turning on the power of the plasma generator. The purpose of performing this step is because the initial flow of the reaction gases SiH4 and Zin 0 just after entering the chemical vapor deposition chamber is extremely unstable. This stabilizing step is performed before turning on the power of the plasma generator. After the flow of the reaction gas is stabilized, turn on the power of the plasma generator to precisely control the rate and quality of thin film deposition. Finally, plasma deposition enhanced chemical vapor deposition (PECVD) is used to perform the deposition step. The reaction gases SiH4 and N2O ions are continuously passed into the chemical vapor deposition chamber, and the power of the plasma generator is turned on. At this time, SiH4 and N2O The ions react on the wafer surface to form silicon dioxide SiO2, and are deposited on the surface of the substrate 10 to form a silicon dioxide film 20, as shown in FIG. In this embodiment, before performing the stabilization step, a pre-flow step is performed with a mixed gas of dinitrogen oxide N20 and nitrogen N2, and the formed silicon dioxide film has a particle diameter per unit area greater than 0.2 microns. The number is less than 30, which is far less than the number of particles of the silicon dioxide film produced by the conventional process. This not only obtains better flatness, but also makes the stress structure of the formed silicon dioxide film more excellent. The method for forming a low-particle-count silicon oxide layer in an integrated circuit according to the present invention is completed. 7 1 ^ ------- 1¾Water ------ 1T ------ ^ (Read the precautions on the back before filling in this page) The paper body and degree of this paper are in accordance with Chinese National Standards (CNS : A4 size · 210x29? Male) B8 ^ v63 B7-II ιτ — V. Description of the invention (γ) In the traditional process, the wafer is sent to the plasma enhanced chemical vapor deposition chamber and the stabilization step is performed directly. Steps Simultaneously open the valves of the two reaction gases of SiH4 and stage 0. Because the amount of SiH4 required during the reaction is small, SiH4 reaches saturation earlier. Therefore, in the initial stage of the stabilization step, about 5 seconds, 9 SiH4 has reached saturation, while N2O has not yet reached saturation * At this time, the ratio of SiH4 / N2O is much larger than that during the formal deposition step. Because of the excessive partial pressure of SiH4, SiH4 will be deposited on the wafer surface earlier and produce irregular particles, which will seriously affect the yield and stability of the product. In this embodiment, the pre-flow step is performed with a mixed gas of dinitrogen oxide N2O and nitrogen before performing the stabilization step. The purpose is to reduce the partial pressure of SiH4, so that SiH4 will not be deposited on the surface of the wafer and cause irregularities. particle. The present invention is described through three specific embodiments to explain the principles and spirit of the present invention. It should be understood that the present invention is not limited to the specific embodiments disclosed. Therefore, any relevant details made under the principles and scope of the present invention The above changes should be regarded as further embodiments of the present invention. I-M ------- Private Clothing ------, ar ------ ^ (诮 Please read the notes on the back before filling this page) Printed by the Staff Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 8 Wood paper corpses and Du Yuan use Chinese national standards (CNS Λ4 Regulations)