TW202223178A - Method of epitaxial wafer manufacture - Google Patents

Method of epitaxial wafer manufacture Download PDF

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TW202223178A
TW202223178A TW110102980A TW110102980A TW202223178A TW 202223178 A TW202223178 A TW 202223178A TW 110102980 A TW110102980 A TW 110102980A TW 110102980 A TW110102980 A TW 110102980A TW 202223178 A TW202223178 A TW 202223178A
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cleaning
polishing
substrate
epitaxial
preparing
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林志鑫
季文明
劉麗英
劉源
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大陸商上海新昇半導體科技有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002—Preparing wafers
    • H01L21/02005—Preparing bulk and homogeneous wafers
    • H01L21/02008—Multistep processes
    • H01L21/0201—Specific process step
    • H01L21/02013—Grinding, lapping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002—Preparing wafers
    • H01L21/02005—Preparing bulk and homogeneous wafers
    • H01L21/02008—Multistep processes
    • H01L21/0201—Specific process step
    • H01L21/02021—Edge treatment, chamfering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02041—Cleaning
    • H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02041—Cleaning
    • H01L21/02057—Cleaning during device manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02634—Homoepitaxy

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  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

The present application provides a method of epitaxial wafer manufacture. The method comprises Step S1: providing a substrate, conducting a double-side polishing to the substrate, and washing the substrate; Step S2: conducting an edge polishing to the substrate, and washing the substrate; Step S3: conducting a final polishing to the substrate, and washing the substrate; Step S4: conducting an epitaxy growth on the obtained substrate; and Step S5: polishing and washing the epitaxial substrate. The present application provides an improved and optimized method of epitaxial wafer manufacture, including the plural polishing steps before the epitaxy growth to ensure excellent environmental conditions for the growth, and the polishing and washing steps after epitaxy growth to ensure the epitaxial layer with flat surface. Therefore, the conventional worse SFQR of the epitaxial surface can be improved, and the production yield of the following device can be increased. By applying the method of the present application, it is not necessary to re-establish the silicon carbide base or the gas flow of the epitaxy device, or match the notch before disposing into the reaction chamber of the epitaxy furnace. The production efficiency can be enhanced and the cost can be reduced.

Description

磊晶晶圓製備方法Epitaxial wafer preparation method

本發明係關於半導體技術領域，特別是關於一種磊晶晶圓製備方法。The present invention relates to the field of semiconductor technology, in particular to a method for preparing epitaxial wafers.

磊晶晶圓是指用磊晶製程在基材表面生長薄膜所得到的單晶矽片。通過在基材（比如矽晶圓）上沉積一層同質或異質的薄膜作為磊晶層，可以實現對基材表面結晶品質與導電性能的改善調控，進而用於高性能的半導體元件製造。隨著半導體元件積體度的日益增加和特徵尺寸的不斷縮小，磊晶層表面平坦度對製程良率以及最終製備的元件性能的影響越來越大。表面平坦度越好，元件良率與性能也越高，因而不斷提升磊晶晶圓表面平坦度是業內不斷追求的目標。Epitaxial wafer refers to a single crystal silicon wafer obtained by growing a thin film on the surface of a substrate by an epitaxial process. By depositing a homogeneous or heterogeneous thin film on a substrate (such as a silicon wafer) as an epitaxial layer, the improvement and regulation of the crystalline quality and conductivity of the substrate surface can be achieved, and then used in the manufacture of high-performance semiconductor components. With the increasing integration of semiconductor devices and the continuous reduction of feature size, the surface flatness of the epitaxial layer has an increasing influence on the process yield and the performance of the final fabricated device. The better the surface flatness, the higher the component yield and performance. Therefore, continuously improving the surface flatness of epitaxial wafers is the goal that the industry is constantly pursuing.

現有的磊晶晶圓製程流程通常如下：基材拋光à清洗à磊晶生長à最終清洗。即現有技術中僅在磊晶生長前進行拋光，磊晶生長後僅進行清洗以去除磊晶層表面的雜質顆粒，所以磊晶層表面的最終邊緣形貌由磊晶生長決定。而磊晶生長會受到晶格晶向的影響，導致在4個90度角的地方，會有較差的SFQR(site flatness front surface referenced least squares/range，正面基準最小平方 / 範圍)。這是因為不同晶面的原子鍵密度不同，鍵合能力也不同，因而磊晶層的生長速率會產生差異。通常而言，晶面上的原子鍵密度越大，鍵合能力越強，磊晶層生長速率就相對地越快，比如矽的(311)晶面的雙層原子面之間的共價鍵密度最小，鍵合能力差，故磊晶層生長速率就慢，而(110)晶面之間的原子鍵密度大，鍵合能力強，磊晶層生長速率就相對較快，導致在4個90度角的地方，磊晶層偏厚。The existing epitaxial wafer manufacturing process is generally as follows: substrate polishing → cleaning → epitaxial growth → final cleaning. That is, in the prior art, only polishing is performed before epitaxial growth, and only cleaning is performed after epitaxial growth to remove impurity particles on the surface of the epitaxial layer, so the final edge morphology of the surface of the epitaxial layer is determined by the epitaxial growth. The epitaxial growth will be affected by the crystal lattice orientation, resulting in a poor SFQR (site flatness front surface referenced least squares/range) at four 90-degree angles. This is because the atomic bond density and bonding ability of different crystal planes are different, so the growth rate of the epitaxial layer will be different. Generally speaking, the greater the density of atomic bonds on the crystal plane, the stronger the bonding ability, and the faster the growth rate of the epitaxial layer, such as the covalent bond between the double atomic planes of the (311) crystal plane of silicon. The density is the smallest and the bonding ability is poor, so the growth rate of the epitaxial layer is slow, while the atomic bond density between the (110) crystal planes is large, the bonding ability is strong, and the growth rate of the epitaxial layer is relatively fast, resulting in 4 At a 90-degree angle, the epitaxial layer is thicker.

SFQR較差的磊晶晶圓會給後續元件製造帶來諸多問題。故而為改善SFQR，現有技術中通常通過重新設計碳化矽基座或是改變磊晶機台的氣流設計，以改變磊晶生長過程中不同方向上的氣流量，以使不同位置的磊晶生長速率趨於一致。但這種方法需經反覆多次調試，且不同的磊晶生長所需的基座和/氣流條件不一致，頻繁調整帶來生產成本的上升和生產效率的下降。Epitaxial wafers with poor SFQR will bring many problems to subsequent component manufacturing. Therefore, in order to improve SFQR, in the prior art, by redesigning the silicon carbide susceptor or changing the airflow design of the epitaxial machine, the airflow in different directions during the epitaxial growth process is changed, so as to make the epitaxial growth rate at different positions. tend to be consistent. However, this method needs to be debugged repeatedly, and the susceptor and/or air flow conditions required for different epitaxial growth are inconsistent, and frequent adjustments bring about an increase in production cost and a decrease in production efficiency.

鑒於以上所述現有技術的缺點，本發明的目的在於提供一種磊晶晶圓製備方法，用於解決現有的磊晶生長流程中，無法解決磊晶生產受到晶格晶向的影響，導致在4個90度角的地方SFQR較差的問題，而重新設計碳化矽基座或是改變磊晶機台的氣流設計則存在調整工作量大，導致生產成本上升和生產效率下降等問題。In view of the shortcomings of the above-mentioned prior art, the object of the present invention is to provide a method for preparing epitaxial wafers, which is used to solve the problem that in the existing epitaxial growth process, the effect of the crystal lattice orientation on epitaxial production cannot be solved, resulting in 4 A 90-degree angle has a problem of poor SFQR, and redesigning the silicon carbide susceptor or changing the airflow design of the epitaxial machine has the problem of large adjustment workload, resulting in increased production costs and decreased production efficiency.

為實現上述目的及其他相關目的，本發明提供一種磊晶晶圓製備方法，包括步驟： S1：提供基材，對基材進行雙面拋光後再清洗； S2：對基材進行邊緣拋光後再清洗； S3：對基材進行最終拋光後再清洗； S4：於最終拋光清洗後得到的基材表面進行磊晶生長； S5：對磊晶生長後的基材依次進行拋光和清洗。 In order to achieve the above purpose and other related purposes, the present invention provides a method for preparing an epitaxial wafer, comprising the steps of: S1: Provide the base material, polish the base material on both sides and then clean it; S2: polishing the edge of the substrate before cleaning; S3: The substrate is cleaned after final polishing; S4: epitaxial growth is performed on the surface of the substrate obtained after final polishing and cleaning; S5: polishing and cleaning the epitaxially grown substrate in sequence.

可選地，步驟S1中，雙面拋光後的清洗包括在惰性氣體氛圍下採用SC-2清洗液進行清洗。Optionally, in step S1, the cleaning after double-sided polishing includes cleaning with SC-2 cleaning solution in an inert gas atmosphere.

可選地，步驟S1中，在採用SC-2清洗液進行清洗前，更包括採用臭氧於雙面拋光後的基材表面生成氧化層的步驟。Optionally, in step S1, before using the SC-2 cleaning solution for cleaning, it further includes a step of using ozone to generate an oxide layer on the surface of the substrate after double-sided polishing.

可選地，步驟S1中，對基材進行雙面拋光的拋光液包含二氧化鈰顆粒、去離子水、表面活性劑及雙氧水。Optionally, in step S1, the polishing solution for performing double-sided polishing on the substrate includes ceria particles, deionized water, surfactant and hydrogen peroxide.

可選地，步驟S2中，邊緣拋光後的清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗。Optionally, in step S2, the cleaning after edge polishing includes cleaning with SC-1 cleaning solution in an inert gas atmosphere.

可選地，步驟S3中，最終拋光後的清洗包括在惰性氣體氛圍下採用去離子水進行清洗。Optionally, in step S3, the cleaning after final polishing includes cleaning with deionized water in an inert gas atmosphere.

可選地，所述基材包括矽基材，磊晶生長包括矽單晶磊晶生長，磊晶生長過程中，通入的氣體包括三氯矽烷和載氣，所述三氯矽烷的流量為1500 sccm-2000 sccm，所述載氣的流量範圍為1000 sccm-1500 sccm。Optionally, the substrate includes a silicon substrate, and the epitaxial growth includes silicon single crystal epitaxial growth. During the epitaxial growth, the gas introduced includes trichlorosilane and a carrier gas, and the flow rate of the trichlorosilane is: 1500 sccm-2000 sccm, the flow range of the carrier gas is 1000 sccm-1500 sccm.

可選地，步驟S5中，對磊晶生長後的基材進行拋光的過程中，拋光液包含二氧化矽顆粒、去離子水、表面活性劑及雙氧水。Optionally, in step S5, in the process of polishing the epitaxially grown substrate, the polishing solution includes silicon dioxide particles, deionized water, surfactant and hydrogen peroxide.

可選地，步驟S5中，對磊晶生長後的基材進行拋光後的清洗，依次包括預清洗、主清洗和最終清洗，其中，所述預清洗包括對磊晶生長後的基材表面進行氧化以生成氧化膜，之後去除氧化膜的步驟；所述主清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗，最終清洗包括在惰性氣體氛圍下採用去離子水進行清洗。Optionally, in step S5, cleaning after polishing is performed on the epitaxially grown substrate, including pre-cleaning, main cleaning, and final cleaning in sequence, wherein the pre-cleaning includes cleaning the surface of the epitaxially grown substrate. The steps of oxidizing to generate an oxide film and then removing the oxide film; the main cleaning includes cleaning with SC-1 cleaning solution under an inert gas atmosphere, and the final cleaning includes cleaning with deionized water under an inert gas atmosphere.

可選地，SC-1清洗液中，氨水、雙氧水和水的體積百分比為1:1:5~1:2:7。Optionally, in the SC-1 cleaning solution, the volume percentages of ammonia water, hydrogen peroxide and water are 1:1:5~1:2:7.

如上所述，本發明的磊晶晶圓製備方法，具有以下有益效果：本發明對現有的磊晶晶圓製備流程重新進行了優化設計，不僅在磊晶生長前進行多次拋光以確保磊晶生長具有良好的生長條件，且在磊晶生長後再次進行拋光清洗，以確保生長出的磊晶層具有平坦表面，可以有效改善磊晶層表面SFQR較差的問題，有利於提高後續的元件生產良率。採用本發明，無需重新設計碳化矽基座或是改變磊晶機台的氣流設計，且本發明適用於所有製程的磊晶晶圓生長，有著較大的商業利用價值。As mentioned above, the epitaxial wafer preparation method of the present invention has the following beneficial effects: the present invention re-optimizes the existing epitaxial wafer preparation process, and not only performs multiple polishing before epitaxial growth to ensure epitaxial growth The growth has good growth conditions, and after epitaxial growth, polishing and cleaning are performed again to ensure that the grown epitaxial layer has a flat surface, which can effectively improve the problem of poor SFQR on the surface of the epitaxial layer, which is conducive to improving the subsequent production of components. Rate. By adopting the present invention, there is no need to redesign the silicon carbide base or change the airflow design of the epitaxial machine, and the present invention is suitable for the growth of epitaxial wafers in all processes, and has great commercial utilization value.

以下通過特定的具體實例說明本發明的實施方式，本領域技術人員可由本說明書所揭露的內容輕易地瞭解本發明的其他優點與功效。本發明還可以通過另外不同的具體實施方式加以實施或應用，本說明書中的各項細節也可以基於不同觀點與應用，在沒有背離本發明的精神下進行各種修飾或改變。The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

請參閱圖1至圖3。需要說明的是，本實施例中所提供的圖示僅以示意方式說明本發明的基本構想，遂圖式中僅顯示與本發明中有關的組件而非按照實際實施時的元件數目、形狀及尺寸繪製，其實際實施時各元件的型態、數量及比例可為一種隨意的改變，且其元件佈局形態也可能更為複雜。See Figures 1 through 3. It should be noted that the diagrams provided in this embodiment are only to illustrate the basic concept of the present invention in a schematic way, so the drawings only show the components related to the present invention rather than the number, shape and number of components in actual implementation. For dimension drawing, the type, quantity and ratio of each element can be arbitrarily changed in actual implementation, and the layout of the element may also be more complicated.

如圖1所示，本發明提供一種磊晶晶圓製備方法，包括步驟： S1：提供基材，對基材進行雙面拋光後再清洗； S2：對基材進行邊緣拋光後再清洗； S3：對基材進行最終拋光後再清洗； S4：於最終拋光清洗後得到的基材表面進行磊晶生長； S5：對磊晶生長後的基材依次進行拋光和清洗。 As shown in FIG. 1, the present invention provides a method for preparing an epitaxial wafer, comprising the steps of: S1: Provide the base material, polish the base material on both sides and then clean it; S2: polishing the edge of the substrate before cleaning; S3: The substrate is cleaned after final polishing; S4: epitaxial growth is performed on the surface of the substrate obtained after final polishing and cleaning; S5: polishing and cleaning the epitaxially grown substrate in sequence.

本發明對現有的磊晶晶圓製備流程重新進行了優化設計，不僅在磊晶生長前進行多次拋光以確保磊晶生長具有良好的生長條件，且在磊晶生長後再次進行拋光清洗，以確保生長出的磊晶層具有平坦表面，可以有效改善磊晶層表面SFQR較差的問題，有利於提高後續的元件生產良率。採用本發明，無需重新設計碳化矽基座或是改變磊晶機台的氣流設計，且本發明適用於所有製程的磊晶晶圓生長，有著較大的商業利用價值。The present invention re-optimizes the existing epitaxial wafer preparation process, and not only performs multiple polishing before epitaxial growth to ensure good growth conditions for epitaxial growth, but also performs polishing and cleaning after epitaxial growth to ensure that the epitaxial growth has good growth conditions. Ensuring that the grown epitaxial layer has a flat surface can effectively improve the problem of poor SFQR on the surface of the epitaxial layer, which is beneficial to improving the yield of subsequent element production. By adopting the present invention, there is no need to redesign the silicon carbide base or change the airflow design of the epitaxial machine, and the present invention is suitable for the growth of epitaxial wafers in all processes, and has great commercial utilization value.

作為示例，所述步驟S1中的基材包括但不限於矽基材、鍺基材、碳化矽基材或其他類型的半導體基材，生長的磊晶層依據基材類型和/或製程的不同或不同，包括但不限於矽單晶磊晶生長，本實施例中並不做具體限制，因為本發明的磊晶晶圓製備方法適於製備所有類型的磊晶晶圓。但在一優選示例中，所述基材為矽基材，生長的磊晶層為矽單晶磊晶。在矽基材表面生長矽單晶磊晶層受基材晶向影響尤其很大，因而採用傳統的方法，僅在磊晶生長前進行拋光難以解決生長出的磊晶層在4個90度角的地方厚度偏大的問題，而本採用本發明製備矽基材的磊晶晶圓可以有效解決此類問題。在進一步的示例中，矽單晶磊晶生長，磊晶生長過程中採用氣相磊晶法，通入的氣體包括三氯矽烷和載氣，所述三氯矽烷的流量為1500 sccm-2000 sccm，所述載氣的流量範圍為1000 sccm-1500 sccm。且在此過程中還可以同時通入氯化氫(HCl)氣體，HCl氣體流量為0-300 sccm。這有利於製備高品質的矽單晶磊晶，氣相磊晶生長的磊晶層與基材具有良好的貼附性。As an example, the substrate in the step S1 includes, but is not limited to, a silicon substrate, a germanium substrate, a silicon carbide substrate or other types of semiconductor substrates, and the epitaxial layer to be grown depends on the type of substrate and/or the process. Or different, including but not limited to silicon single crystal epitaxial growth, which is not specifically limited in this embodiment, because the epitaxial wafer preparation method of the present invention is suitable for preparing all types of epitaxial wafers. However, in a preferred example, the substrate is a silicon substrate, and the epitaxial layer to be grown is a single-crystal silicon epitaxial. The growth of a silicon single crystal epitaxial layer on the surface of a silicon substrate is particularly affected by the crystal orientation of the substrate. Therefore, using the traditional method, only polishing before epitaxial growth is difficult to solve the problem that the grown epitaxial layer is at four 90-degree angles. The problem that the thickness is too large in places where the present invention is used to prepare the epitaxial wafer of the silicon substrate can effectively solve such problems. In a further example, the epitaxial growth of silicon single crystal is carried out, and the gas phase epitaxy method is used in the epitaxial growth process, and the gas introduced includes trichlorosilane and a carrier gas, and the flow rate of the trichlorosilane is 1500 sccm-2000 sccm , the flow rate of the carrier gas ranges from 1000 sccm to 1500 sccm. And in this process, hydrogen chloride (HCl) gas can also be introduced at the same time, and the flow rate of the HCl gas is 0-300 sccm. This is conducive to the preparation of high-quality silicon single crystal epitaxy, and the epitaxial layer grown by vapor phase epitaxy has good adhesion to the substrate.

作為示例，步驟S1中，對基材進行雙面拋光的拋光液包含二氧化鈰顆粒、去離子水、表面活性劑及雙氧水。採用包含二氧化鈰顆粒的拋光液進行拋光，有利於提高拋光效率。在進一步的示例中，拋光液中，二氧化鈰顆粒的質量濃度為0.5~10 wt%，雙氧水的質量濃度為2%~4%。As an example, in step S1, the polishing liquid for performing double-sided polishing on the substrate includes ceria particles, deionized water, surfactant and hydrogen peroxide. Using a polishing liquid containing ceria particles for polishing is beneficial to improve polishing efficiency. In a further example, in the polishing liquid, the mass concentration of ceria particles is 0.5-10 wt%, and the mass concentration of hydrogen peroxide is 2%-4%.

作為示例，步驟S1中，雙面拋光後的清洗包括在惰性氣體氛圍下採用SC-2清洗液進行清洗，所述SC-2清洗液的配方可以為HCl：H 2O 2：H 2O=1:1:6~1:2:8，清洗時間可以根據製程需要而定，比如為1~30 min。通過採用具有較強腐蝕性的清洗液清洗，可以有效去除基材表面的雜質顆粒。惰性氣體氛圍包括但不限於氮氣和氬氣，亦或是其組合，通過通入惰性氣體，避免基材表面被進一步氧化。 As an example, in step S1, the cleaning after double-sided polishing includes cleaning with SC-2 cleaning solution in an inert gas atmosphere, and the formula of the SC-2 cleaning solution may be HCl: H 2 O 2 : H 2 O= 1:1:6~1:2:8, the cleaning time can be determined according to the needs of the process, such as 1~30 min. The impurity particles on the surface of the substrate can be effectively removed by cleaning with a strong corrosive cleaning solution. The inert gas atmosphere includes, but is not limited to, nitrogen and argon, or a combination thereof. By passing the inert gas, the surface of the substrate is prevented from being further oxidized.

在進一步的示例中，步驟S1中，在採用SC-2清洗液進行清洗前，更包括採用臭氧於雙面拋光後的基材表面生成氧化層的步驟。由於之前的拋光過程中使用的帶金屬元素的拋光液顆粒可能殘留在基材表面，容易導致基材內部的金屬缺陷（比如造成後續製備的元件短路），故對雙面拋光後的基材表面進行氧化以生成金屬氧化膜以將金屬離子牢固鎖定，之後再通過酸性清洗液去除氧化膜，可以有效避免金屬離子在基材表面的殘留。In a further example, in step S1, before using the SC-2 cleaning solution for cleaning, it further includes the step of using ozone to generate an oxide layer on the surface of the substrate after double-sided polishing. Since the particles of the polishing liquid with metal elements used in the previous polishing process may remain on the surface of the substrate, it is easy to cause metal defects inside the substrate (such as short-circuiting of the components prepared later), so the surface of the substrate after double-sided polishing Oxidation is performed to form a metal oxide film to lock the metal ions firmly, and then the oxide film is removed by an acidic cleaning solution, which can effectively avoid the residue of metal ions on the surface of the substrate.

作為示例，步驟S2中，邊緣拋光後的清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗，所述SC-1清洗液中，氨水、雙氧水和水的體積百分比可以為1:1:5~1:2:7。此步驟採用弱鹼性清洗液進行清洗，可以有效減少對基材表面的損傷。同樣地，惰性氣體包括但不限於氮氣和氬氣中的一種或多種。As an example, in step S2, the cleaning after edge polishing includes using SC-1 cleaning solution for cleaning under an inert gas atmosphere. In the SC-1 cleaning solution, the volume percentages of ammonia water, hydrogen peroxide and water may be 1:1: 5~1:2:7. In this step, a weak alkaline cleaning solution is used for cleaning, which can effectively reduce the damage to the surface of the substrate. Likewise, inert gases include, but are not limited to, one or more of nitrogen and argon.

所述步驟S1、S2和S3的拋光工序中使用的拋光液可以相同或不同，比如可以均使用包含二氧化鈰顆粒、去離子水、表面活性劑及雙氧水的拋光液，但其中的組分可以根據需要調整，因此這三個步驟可以在同一機台上連續進行，避免轉換機台造成基材損傷和生產效率的下降。例如，步驟S1中進行雙面拋光時，二氧化鈰顆粒和雙氧水的質量百分比的含量高於後續兩個步驟，尤其是對基材進行最終拋光時的拋光液中的二氧化鈰顆粒和雙氧水的質量百分比最低，以更有效地控制拋光效率。The polishing liquid used in the polishing process of the steps S1, S2 and S3 may be the same or different, for example, a polishing liquid containing ceria particles, deionized water, surfactant and hydrogen peroxide may be used, but the components may be Adjust as needed, so these three steps can be performed continuously on the same machine to avoid substrate damage and production efficiency drop caused by changing machines. For example, when double-sided polishing is performed in step S1, the mass percentage content of ceria particles and hydrogen peroxide is higher than that in the following two steps, especially the content of ceria particles and hydrogen peroxide in the polishing solution when the substrate is finally polished. The lowest mass percentage is used to control polishing efficiency more effectively.

作為示例，步驟S3中，最終拋光後的清洗包括在惰性氣體氛圍下採用去離子水進行清洗，以儘量減少殘留的清洗液對後續製程的影響。該步驟之後可以進行烘乾，以去除基材表面的水分。As an example, in step S3, the cleaning after the final polishing includes cleaning with deionized water in an inert gas atmosphere, so as to minimize the influence of the residual cleaning liquid on the subsequent process. This step may be followed by drying to remove moisture from the surface of the substrate.

作為示例，步驟S5中，對磊晶生長後的基材進行拋光的過程中，拋光液包含二氧化矽顆粒、去離子水、表面活性劑及雙氧水。採用包含二氧化矽顆粒的拋光液進行磊晶生長後的拋光，可以有效控制拋光速率，同時避免因使用包括金屬離子的拋光液導致金屬離子殘留於磊晶層中。磊晶生長後的拋光過程中，厚度偏大處因上表面較高而最先與拋光頭接觸，故而受到較大的壓力，導致拋光速率較快，由此可以實現自動修正SFQR的效果。As an example, in step S5, in the process of polishing the epitaxially grown substrate, the polishing solution includes silicon dioxide particles, deionized water, surfactant and hydrogen peroxide. Using the polishing solution containing silicon dioxide particles for polishing after epitaxial growth can effectively control the polishing rate, and at the same time avoid metal ions remaining in the epitaxial layer due to the use of the polishing solution including metal ions. During the polishing process after epitaxial growth, the part with large thickness first contacts the polishing head because the upper surface is higher, so it is subjected to greater pressure, resulting in a faster polishing rate, so that the effect of automatic correction of SFQR can be achieved.

作為示例，步驟S5中，對磊晶生長後的基材進行拋光後的清洗依次包括預清洗、主清洗和最終清洗，其中，所述預清洗包括對磊晶生長後的基材表面進行氧化以生成氧化膜，之後去除氧化膜的步驟；所述主清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗，最終清洗包括在惰性氣體氛圍下採用去離子水進行清洗。在進一步的示例中，SC-1清洗液中，氨水、雙氧水和水的體積百分比為1:1:5~1:2:7。通過多步清洗，確保磊晶層表面無異物殘留，提高清潔度。As an example, in step S5, the cleaning after polishing the epitaxially grown substrate sequentially includes pre-cleaning, main cleaning and final cleaning, wherein the pre-cleaning includes oxidizing the surface of the epitaxially grown substrate to The steps of generating an oxide film and then removing the oxide film; the main cleaning includes cleaning with SC-1 cleaning solution under an inert gas atmosphere, and the final cleaning includes cleaning with deionized water under an inert gas atmosphere. In a further example, in the SC-1 cleaning solution, the volume percentages of ammonia water, hydrogen peroxide and water are 1:1:5~1:2:7. Through multi-step cleaning, it is ensured that no foreign matter remains on the surface of the epitaxial layer, and the cleanliness is improved.

發明人進行了試驗以驗證本發明的效果。該試驗過程包括先按磊晶製程分別在3個基材表面各自生長磊晶層，然後沿著圓周量測148mm處的厚度（前值），經過最終拋光步驟，拋光墊為T6（非不織布材質，為聚氨酯材質），屬於硬的拋光墊，再沿著圓周量測148mm處的厚度（後值），比較前後值的不同，得到的結果如圖2和圖3所示。從圖2及圖3可以看到，針對比較突出的位置，在磊晶生長後進行拋光，可以實現邊緣修正減少突起，明顯改善邊緣厚度的差異，尤其是形成的磊晶層越厚，拋光時間越長，改善效果越突出。The inventors conducted experiments to verify the effects of the present invention. The test process includes firstly growing epitaxial layers on the surfaces of the three substrates according to the epitaxial process, then measuring the thickness (previous value) at 148mm along the circumference, and after the final polishing step, the polishing pad is T6 (non-woven material). , is made of polyurethane), which is a hard polishing pad, and then measures the thickness (post value) at 148mm along the circumference, and compares the difference between the front and rear values. The results are shown in Figure 2 and Figure 3. As can be seen from Figure 2 and Figure 3, for the more prominent positions, polishing after epitaxial growth can achieve edge correction to reduce protrusions and significantly improve the difference in edge thickness, especially the thicker the epitaxial layer formed, the longer the polishing time. The longer it is, the more prominent the improvement effect is.

綜上所述，本發明提供一種磊晶晶圓製備方法，包括步驟：S1：提供基材，對基材進行雙面拋光後再清洗；S2：對基材進行邊緣拋光後再清洗；S3：對基材進行最終拋光後再清洗；S4：於最終拋光清洗後得到的基材表面進行磊晶生長；S5：對磊晶生長後的基材依次進行拋光和清洗。本發明對現有的磊晶晶圓製備流程重新進行了優化設計，不僅在磊晶生長前進行多次拋光以確保磊晶生長具有良好的生長條件，且在磊晶生長後再次進行拋光清洗，以確保生長出的磊晶層具有平坦表面，可以有效改善磊晶層表面SFQR較差的問題，有利於提高後續的元件生產良率。採用本發明，通過最終拋光調試邊緣形貌可獲得較高平坦度的磊晶晶圓，不用再分磊晶晶圓與拋光片，有利於簡化晶圓廠內的物料管理；不必重新設計碳化矽基座或是磊晶機台氣流設計，進磊晶爐反應腔之前不用對notch角度，有助於提高生產效率及降低生產成本，且本發明適用於所有製程的磊晶晶圓製備。所以，本發明有效克服了現有技術中的種種缺點而具高度產業利用價值。To sum up, the present invention provides an epitaxial wafer preparation method, which includes the steps: S1: providing a substrate, and cleaning the substrate after double-sided polishing; S2: cleaning the substrate after edge polishing; S3: The substrate is cleaned after final polishing; S4: Epitaxial growth is performed on the surface of the substrate obtained after final polishing and cleaning; S5: The substrate after epitaxial growth is polished and cleaned in sequence. The present invention re-optimizes the existing epitaxial wafer preparation process, and not only performs multiple polishing before epitaxial growth to ensure good growth conditions for epitaxial growth, but also performs polishing and cleaning after epitaxial growth to ensure that the epitaxial growth has good growth conditions. Ensuring that the grown epitaxial layer has a flat surface can effectively improve the problem of poor SFQR on the surface of the epitaxial layer, which is beneficial to improving the yield of subsequent element production. By adopting the present invention, epitaxial wafers with higher flatness can be obtained by final polishing and debugging the edge morphology, and there is no need to separate epitaxial wafers and polishing wafers, which is beneficial to simplify the material management in the wafer factory; it is unnecessary to redesign silicon carbide The airflow design of the susceptor or the epitaxial machine does not need to align the notch angle before entering the reaction chamber of the epitaxial furnace, which helps to improve the production efficiency and reduce the production cost, and the present invention is suitable for the preparation of epitaxial wafers in all processes. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

上述實施例僅例示性說明本發明的原理及其功效，而非用於限制本發明。任何熟悉此技術的人士皆可在不違背本發明的精神及範疇下，對上述實施例進行修飾或改變。因此，舉凡所屬技術領域中具有通常知識者在未脫離本發明所揭示的精神與技術思想下所完成的一切等效修飾或改變，仍應由本發明的權利要求所涵蓋。The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

S1~S5:步驟S1~S5: Steps

圖1為本發明提供的磊晶晶圓製備方法的流程圖。FIG. 1 is a flow chart of a method for preparing an epitaxial wafer provided by the present invention.

圖2為採用本發明的磊晶晶圓製備方法製備的多片磊晶晶圓，完成磊晶生長後進行拋光前與拋光後的厚度分佈曲線示意圖，其中，曲線①為第一片磊晶晶圓磊晶後未拋光前的厚度分佈曲線，曲線②為第一片磊晶晶圓磊晶且拋光後的厚度分佈曲線；曲線③為第二片磊晶晶圓磊晶後未拋光前的厚度分佈曲線，曲線④為第二片磊晶晶圓磊晶且拋光後的厚度分佈曲線；曲線⑤為第三片磊晶晶圓磊晶後未拋光前的厚度分佈曲線，曲線⑥為第三片磊晶晶圓磊晶且拋光後的厚度分佈曲線。2 is a schematic diagram of thickness distribution curves of multiple epitaxial wafers prepared by the epitaxial wafer preparation method of the present invention, before and after polishing after epitaxial growth is completed, wherein curve ① is the first epitaxial wafer The thickness distribution curve of the epitaxial wafer before and after epitaxy, curve ② is the thickness distribution curve of the first epitaxial wafer after epitaxy and polishing; curve ③ is the thickness of the second epitaxial wafer before and after epitaxy Distribution curve, curve ④ is the thickness distribution curve of the second epitaxial wafer after epitaxial deposition and polishing; curve ⑤ is the thickness distribution curve of the third epitaxial wafer after epitaxy and before polishing, and curve ⑥ is the third epitaxial wafer thickness distribution curve Thickness profile of an epitaxial wafer after epitaxial and polished.

圖3為採用本發明的磊晶晶圓製備方法製備的多片磊晶晶圓，完成磊晶生長後進行拋光前與拋光後的厚度差異比較圖。3 is a comparison diagram of the difference in thickness of multiple epitaxial wafers prepared by the epitaxial wafer preparation method of the present invention, before and after polishing after epitaxial growth is completed.

S1~S5:步驟 S1~S5: Steps

Claims (10)

一種磊晶晶圓製備方法，包括步驟： S1：提供基材，對基材進行雙面拋光後再清洗； S2：對基材進行邊緣拋光後再清洗； S3：對基材進行最終拋光後再清洗； S4：於最終拋光清洗後得到的基材表面進行磊晶生長；及 S5：對磊晶生長後的基材依次進行拋光和清洗。 A method for preparing epitaxial wafers, comprising the steps of: S1: Provide the base material, polish the base material on both sides and then clean it; S2: polishing the edge of the substrate before cleaning; S3: The substrate is cleaned after final polishing; S4: epitaxial growth is performed on the surface of the substrate obtained after final polishing and cleaning; and S5: polishing and cleaning the epitaxially grown substrate in sequence. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，步驟S1中，雙面拋光後的清洗包括在惰性氣體氛圍下採用SC-2清洗液進行清洗。The method for preparing epitaxial wafers as described in item 1 of the patent application scope, wherein, in step S1, the cleaning after double-sided polishing includes cleaning with SC-2 cleaning solution in an inert gas atmosphere. 如申請專利範圍第2項所述的磊晶晶圓製備方法，其中，步驟S1中，在採用SC-2清洗液進行清洗前還包括採用臭氧於雙面拋光後的基材表面生成氧化層的步驟。The method for preparing epitaxial wafers as described in item 2 of the scope of the patent application, wherein, in step S1, before using the SC-2 cleaning solution for cleaning, it also includes using ozone to generate an oxide layer on the surface of the substrate after double-sided polishing. step. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，步驟S1中，對基材進行雙面拋光的拋光液包含二氧化鈰顆粒、去離子水、表面活性劑及雙氧水。The method for preparing epitaxial wafers according to item 1 of the claimed scope, wherein, in step S1 , the polishing solution for performing double-sided polishing on the substrate comprises ceria particles, deionized water, surfactant and hydrogen peroxide. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，步驟S2中，邊緣拋光後的清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗。The method for preparing an epitaxial wafer as described in item 1 of the patent application scope, wherein, in step S2, the cleaning after edge polishing includes cleaning with SC-1 cleaning solution in an inert gas atmosphere. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，步驟S3中，最終拋光後的清洗包括在惰性氣體氛圍下採用去離子水進行清洗。The method for preparing an epitaxial wafer as described in item 1 of the patent application scope, wherein, in step S3, the cleaning after final polishing includes cleaning with deionized water in an inert gas atmosphere. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，所述基材包括矽基材，磊晶生長包括矽單晶磊晶生長，磊晶生長過程中，通入的氣體包括三氯矽烷和載氣，所述三氯矽烷的流量為1500 sccm-2000 sccm，所述載氣的流量範圍為1000 sccm-1500 sccm。The method for preparing an epitaxial wafer according to item 1 of the claimed scope, wherein the base material comprises a silicon base material, the epitaxial growth comprises silicon single crystal epitaxial growth, and the gas introduced during the epitaxial growth process comprises Trichlorosilane and a carrier gas, the flow rate of the trichlorosilane is 1500 sccm-2000 sccm, and the flow rate of the carrier gas is 1000 sccm-1500 sccm. 如申請專利範圍第1項所述的磊晶晶圓製備方法，其中，步驟S5中，對磊晶生長後的基材進行拋光的過程中，拋光液包含二氧化矽顆粒、去離子水、表面活性劑及雙氧水。The method for preparing epitaxial wafers as described in item 1 of the scope of the patent application, wherein, in step S5, in the process of polishing the epitaxially grown substrate, the polishing liquid contains silicon dioxide particles, deionized water, surface Active agent and hydrogen peroxide. 如申請專利範圍第1-8項任一項所述的磊晶晶圓製備方法，其中，步驟S5中，對磊晶生長後的基材進行拋光後的清洗依次包括預清洗、主清洗和最終清洗，其中，所述預清洗包括對磊晶生長後的基材表面進行氧化以生成氧化膜，之後去除氧化膜的步驟；所述主清洗包括在惰性氣體氛圍下採用SC-1清洗液進行清洗，最終清洗包括在惰性氣體氛圍下採用去離子水進行清洗。The method for preparing epitaxial wafers according to any one of the claims 1 to 8 of the scope of the application, wherein, in step S5, the cleaning after polishing the epitaxially grown substrate sequentially includes pre-cleaning, main cleaning and final cleaning. Cleaning, wherein the pre-cleaning includes the steps of oxidizing the surface of the substrate after epitaxial growth to generate an oxide film, and then removing the oxide film; the main cleaning includes cleaning with SC-1 cleaning solution in an inert gas atmosphere , the final cleaning involves cleaning with deionized water under an inert gas atmosphere. 如申請專利範圍第9項所述的磊晶晶圓製備方法，其中，SC-1清洗液中，氨水、雙氧水和水的體積百分比為1:1:5~1:2:7。The method for preparing epitaxial wafers as described in item 9 of the patent application scope, wherein, in the SC-1 cleaning solution, the volume percentages of ammonia water, hydrogen peroxide and water are 1:1:5~1:2:7.
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