448 70 5 五、發明說明（u 本發明提供一種電漿點火（plasma striking)方法’ 尤指一種高電漿密度蝕刻機台（high density plasma etcher，簡稱HDP etcher)的電漿點火方法β 半導體製程中經常以電漿蝕刻機台來進行半導體晶片 所需要的非等向性蝕刻。進行電漿蝕刻製程時，必須先進 行電漿點火，以使蝕刻機台的真空艙内達到足夠的電漿濃 度，然後才能對半導體晶片進行蝕刻製程。因此須在一預 定的氣壓溫度環境下，通入預定要進行的蝕刻氣體，並先 以一個較小的無線電頻率（radio frequency，簡稱RF)功 率來使電漿點火》當真空艙内的狀態穩定之後，才通入夠 量的蝕刻氣體流量，並且施加夠大的R F功率以及交直流偏 壓（AC&DC bias)，以對半導體晶片進行蝕刻。 隨著電漿蝕刻機台的演進，真空艙内的氣壓也愈來愈 低，這種電装姓刻機台即為HDP etcher。但是直接以預定 要進行的蝕刻氣體可能無法使HDP etcher的完成電漿點 火，必須以某些特殊的氣體來進行電漿點火，等到真空艙 的電漿狀態穩定之後才改通入蝕刻所需的氣體，以進行蝕 刻製程。 請參閱圖一，圖一為一種HDP etcher的示意圖e HDP etcher 10包含有一真空艙12 ，一用來吸覆一半導體晶片 14 之靜電吸座（electro-static chuck，簡稱ESC)16 設於448 70 5 V. Description of the invention (u The present invention provides a plasma ignition method ', especially a plasma ignition method for high density plasma etcher (HDP etcher) β semiconductor process The plasma etching machine is often used to perform the anisotropic etching of semiconductor wafers. When performing the plasma etching process, the plasma ignition must be performed first to achieve a sufficient plasma concentration in the vacuum chamber of the etching machine. , And then the semiconductor wafer can be etched. Therefore, it is necessary to pass a predetermined etching gas under a predetermined pressure and temperature environment, and first use a small radio frequency (RF) power to make electricity. "Pulp ignition" When the state in the vacuum chamber is stable, a sufficient amount of etching gas flow is passed in, and a sufficient RF power and AC & DC bias are applied to etch the semiconductor wafer. The evolution of the plasma etching machine, the air pressure in the vacuum chamber is getting lower and lower, this type of electrical equipment is called HDP etcher. The etching gas to be performed may not enable the plasma ignition of HDP etcher to be completed. Plasma ignition must be performed with some special gases. After the plasma state of the vacuum chamber is stable, the gas required for etching is switched in for Etching process. Please refer to FIG. 1. FIG. 1 is a schematic diagram of HDP etcher. E HDP etcher 10 includes a vacuum chamber 12 and an electro-static chuck (ESC) 16 for covering a semiconductor wafer 14. to
ίΜ ϊϊ 448705 五、發明說明（2) 真空艙12底部，以及一内線圈（inner coil)is與一外線圈 (outer coil)20設於真空艙12上部，用來通入電感rf功 率。習知對HDP etcher 10的電漿點火方法是以一氣艘供 應裝置22對真空艙12提供200sccm的氬氣（arg0n)，並且以 一電源供應裝置分別對外線圈2 0及内線圈1 8提供2 〇 0 0 W的 電感RF功率，使真空艙12内之氣體形成電漿，以完成電漿 點火。 請參閱圖二至圖四，圖二至圖四為半導體晶片14利用 習知電漿點火方法進行的電漿蝕刻製程的示意圖^如圖二 所示’半導體晶片14包含有一基底30，基底30上設有一含 有複數孔洞32之光阻層34，並且孔洞32的側壁都會近乎垂 直。半導體晶片14須置放於ESC16上，以進行電聚钱刻製 程β在以習知方法完成電漿點火之後，電源供應裝置會對 ESC16提供一個近乎1〇〇〇伏特（v〇lt)的直流電壓，用來使 E S C 1 6吸覆半導體晶片丨4 ’然後才開始進行蝕刻。如圖三 所，’ ESC16上的直流電壓會在半導體晶片14上形成一個 f場’造成真空艙12中游離的氬離子36強烈地轟擊半導體 晶片14。如圖四所示，光阻層34在氬離子36強烈地轟擊 下’孔洞3 2的侧壁會受損耗而變的傾斜，而形成具傾斜側 孔洞3 3及厚度不一致光阻層3 4。由於習知電漿點火方 . 強二、的離子森擊（i〇n bombardment)，因此會影響到 ^ Ϊ阳片上之光阻層的輪廊（p r 0 f丨1 e ) ’導致融刻後半 ¥ B日片14上的輪廓和臨界尺寸（crHicai dimensi〇n)均ίΜ ϊϊ 448705 V. Description of the invention (2) The bottom of the vacuum chamber 12 and an inner coil is and an outer coil 20 are arranged on the upper part of the vacuum chamber 12 to pass the rf power of the inductor. The conventional plasma ignition method for HDP etcher 10 is to provide 200 sccm of argon (arg0n) to the vacuum chamber 12 by a gas ship supply device 22, and provide a power supply device with an external coil 20 and an internal coil 18 respectively. 0 0 W of inductive RF power causes the gas in the vacuum chamber 12 to form a plasma to complete the plasma ignition. Please refer to FIGS. 2 to 4. FIGS. 2 to 4 are schematic diagrams of a plasma etching process of a semiconductor wafer 14 using a conventional plasma ignition method. ^ As shown in FIG. 2 ′, the semiconductor wafer 14 includes a substrate 30 on the substrate 30. A photoresist layer 34 including a plurality of holes 32 is provided, and the sidewalls of the holes 32 are nearly vertical. The semiconductor chip 14 must be placed on the ESC16 to perform the electric coining process β. After the plasma ignition is completed in a conventional manner, the power supply device will provide the ESC16 with a DC of approximately 1,000 volts (volts). The voltage is used to cause the ESC 16 to absorb the semiconductor wafer 4 ′ before the etching is started. As shown in Fig. 3, 'the DC voltage on the ESC 16 will form an f-field on the semiconductor wafer 14', causing the free argon ions 36 in the vacuum chamber 12 to strongly bombard the semiconductor wafer 14. As shown in FIG. 4, the photoresist layer 34 is inclined by the loss and the sidewall of the hole 32 under the strong bombardment of argon ions 36, and the photoresist layer 34 having a sloped side and a non-uniform thickness is formed. Due to the known plasma ignition side, the strong second, the ion bombardment (I〇n bombardment), so it will affect the photoresistance layer on the Liyang film (pr 0 f 丨 1 e) 'resulting in the second half of melting ¥ B Day 14 The outline and critical dimensions (crHicai dimensi〇n) are both
448705 五、發明說明（3) 難以控制0 因此 本 發 明 的主要 @ 的 在 於提 供 一 種 電 漿 點 火 (P la s ina St r i ki ng)方法 ，使得半 導體晶片在真正的1 陡刻 製 程 開始 之 前 光阻層 上 的 輪 廓均 可 以 保 持 一 定 的容 忍 範 圍 内 ，使 得 蝕 刻 後半導 體 晶 片 1 4上 的 輪 fWf 廓 和 臨 界 尺寸 均 能 得 到 良好 的 結 果 〇 圖 示 之簡 單 說 明 圖 -^ 為習 知HDP etcher 的 示 意 圖。 圖 至圖 四 為 半 導體晶 片 利 用 習知 電 漿 點 火 方 法 進行 的 電 漿 蝕 刻製 程 的 示 意圖。 圖 五 為一 種 使 用 本發明 方 法 之HDP etch e r 的 示 意 圖。 圖 六 至圖 八 為 半 導體晶 片 利 用 本發 明 電 漿 點 火 方 法進 行 的 電 漿 蝕刻 製 程 的 示意圖 0 圖 示 之符 號 說 明 40 HDP etch e r 42 真 空 艙 44 半導 體 晶 片 46 ESC 48 内線 圈 50 外 線 圈 52 氣體 供 應 裝 置 54 電 源 供 應 裝 置 60 基底 62 孔 洞 64 光阻 層 6 6 氬 離 子 68 而分 子 層448705 V. Description of the invention (3) It is difficult to control 0. Therefore, the main thing of the present invention is to provide a plasma ignition (Plasina Striking) method, which makes the semiconductor wafer photoresist before the real 1st steep process begins. The contours on the layers can be maintained within a certain tolerance range, so that the wheel fWf profile and the critical dimension on the semiconductor wafer 14 after etching can obtain good results. The simple illustration of the diagram-^ is a schematic diagram of the conventional HDP etcher . Figures to Figure 4 are schematic views of the plasma etching process of a semiconducting wafer using the conventional plasma ignition method. Figure 5 is a schematic diagram of HDP etch e r using the method of the present invention. Figures 6 to 8 are schematic diagrams of the plasma etching process of a semiconductor wafer using the plasma ignition method of the present invention. 0 Symbol descriptions 40 HDP etcher 42 Vacuum chamber 44 Semiconductor wafer 46 ESC 48 Inner coil 50 Outer coil 52 Gas supply Device 54 Power supply device 60 Base 62 Hole 64 Photoresist layer 6 6 Ar ion 68 and molecular layer
448 70 5 五、發明說明（4) 請參閱圖五，圖五為一種使用本發明，方法之HDP etcher40的示意圖。本發明提供一種HDP etcher的電裂點 火方法°如圖五所示，HDP etcher 40包含有一個真空餘 42，其内部可以進行一半導體晶片44之蝕刻製程。HDP etcher40另包含有一 ESC 46設於真空臉42内之底部，用來 以靜電吸覆半導體晶片44以進行蝕刻製程，一内線圈48以 及一外線圈50設於真空艙4 2内之上部，用來通入RF功率， 一氣體供應裝置52，用來供應真空艙4 2所需的氣體，以及 一電源供應裝置54 ’用來提供蝕刻製程所需的電源及能 量。 卜在本發明之電漿點火方法中’氣體供應裝置52提供氬 氣（argon ’ Ar)與碳氟化合物（fiu〇r〇carb〇n)之氣體來進 行¥裳點火。碳氟化合物可為化學式表示為CxFy之氣體， 其中X為3、4或5，而y為6或δ。氬氣的氣體流量控制在50 至3y〇sccm ’而碳氟化合物之氣體流量控制在5至25sccm。 在能量方面’電源供應裝置54提供1 000至1 500瓦（W)的内 @RF功率予内線圈48 ’以及提供0至500瓦U)的外圈RF功 率予外線圈50 ^當真空艙42内氣壓保持在1至1〇〇毫托耳 (mT〇rr)時，可以使真空艙“内之氣體形成電漿，完成電 清參閱圖六至圖八，圖六至圖八為半導體晶片44利用448 70 5 V. Description of the invention (4) Please refer to FIG. 5, which is a schematic diagram of a HDP etcher40 using the method and method of the present invention. The present invention provides an electrical cracking method for HDP etcher. As shown in FIG. 5, HDP etcher 40 includes a vacuum chamber 42, and an etching process of a semiconductor wafer 44 can be performed inside the HDP etcher 40. HDP etcher40 also includes an ESC 46 located in the bottom of the vacuum face 42 for electrostatically absorbing the semiconductor wafer 44 for the etching process. An inner coil 48 and an outer coil 50 are provided on the upper part of the inside of the vacuum chamber 42. RF power is supplied, a gas supply device 52 is used to supply the gas required for the vacuum chamber 42, and a power supply device 54 'is used to provide the power and energy required for the etching process. In the plasma ignition method of the present invention, the 'gas supply device 52 supplies gas of argon (Aron' Ar) and fluorocarbon (fiu〇r〇carb〇n) for ignition. The fluorocarbon may be a gas represented by the chemical formula CxFy, where X is 3, 4 or 5, and y is 6 or δ. The gas flow rate of argon is controlled to 50 to 3 sccm 'and the gas flow rate of fluorocarbon is controlled to 5 to 25 sccm. In terms of energy, the 'power supply device 54 provides 1,000 to 1,500 watts (W) of inner @RF power to the inner coil 48' and the outer ring RF power to 0 to 500 watts of U) to the outer coil 50 ^ When the vacuum chamber 42 When the internal air pressure is maintained at 1 to 100 millitorr (mT0rr), the gas in the vacuum chamber can be formed into a plasma to complete the electric cleaning. Refer to FIGS. 6 to 8, which are semiconductor wafers 44 use
448 70 5 五、發明說明（5) 本發明電漿點火方法進行電漿蝕刻製程的示意圖。如圖六 所示，置於真空艙4 2中的半導體晶片44包含有一基底60， 基底60上設有一含有複數孔洞62之光阻肩^4，並且孔洞64 的側壁都近乎垂直。利用本發明電漿點火方法對半導體晶 片44進行電漿蝕刻製程時，先將半導體晶片44置放於 ESC46上，然後進行本發明電漿點火。如圖七所示，本發 明電漿點火方法在電漿點火時，能在半導體晶片44上形成 一層高分子唐（polymer layer)68。 然後，以ESC46施加一 8 0 0至1 2 0 0直流電壓，用來以一 靜電吸力吸復半導體晶片44，此時ESC46上的直流電壓會 在半導體晶片44表面形成一電場，導致電漿中的氬離子66 開始轟擊半導體晶片44以進行钮刻製程。由於本發明方法 中使用了碳氟化合物作為電漿點火氣體之一，在電漿點火 時，碳氟化合物便會在半導體晶片44表面開始沉積一層高 勿子廣68，只要善加調整高分子層68的沉積速率與氬離子 66的轟擊能量’使沉積速率與轟擊能量達到一個平衡的狀 態，光阻層6 4的輪廓變化便能控制在一定的範圍。如圖八 所示’電漿點火之後，除了孔洞62上方的轉角處因為尖端 電場放大的效應而圓K(rounding)外’其餘的光阻層64的 輪廓幾乎都保持不變，也就是光阻層64由上方看的厚度都 幾乎一樣，這樣的光阻層6 4能使後序的蝕刻製程有足夠的 阻播，對於蝕刻完後的半導體晶片44上的輪廓與臨界尺寸 都能給予良好控制。448 70 5 V. Description of the invention (5) Schematic diagram of the plasma etching process of the plasma ignition method of the present invention. As shown in FIG. 6, the semiconductor wafer 44 placed in the vacuum chamber 42 includes a substrate 60, and a photoresistor 4 including a plurality of holes 62 is provided on the substrate 60, and the sidewalls of the holes 64 are almost vertical. When the plasma etching process of the semiconductor wafer 44 is performed by the plasma ignition method of the present invention, the semiconductor wafer 44 is first placed on the ESC 46, and then the plasma ignition of the present invention is performed. As shown in Fig. 7, the plasma ignition method of the present invention can form a polymer layer 68 on the semiconductor wafer 44 when the plasma is ignited. Then, a DC voltage of 800 to 12 000 is applied to the ESC 46 to attract the semiconductor wafer 44 with an electrostatic attraction. At this time, the DC voltage on the ESC 46 will form an electric field on the surface of the semiconductor wafer 44 and cause a plasma. The argon ions 66 begin to bombard the semiconductor wafer 44 for the button-etching process. Because the fluorocarbon is used as one of the plasma ignition gas in the method of the present invention, when the plasma is ignited, the fluorocarbon will start to deposit a layer of Gao Ziguang 68 on the surface of the semiconductor wafer 44 as long as the polymer layer is adjusted properly The deposition rate of 68 and the bombardment energy of argon ion 66 'make the deposition rate and the bombardment energy reach a balanced state, and the profile change of the photoresist layer 64 can be controlled within a certain range. As shown in FIG. 8 'after the plasma ignition, except for the corner K above the hole 62 due to the amplification of the electric field at the tip, the photoresist layer 64 has almost the same profile, that is, the photoresist The thickness of the layer 64 is almost the same when viewed from above. Such a photoresist layer 64 can sufficiently suppress the subsequent etching process, and can give good control to the contour and critical size of the semiconductor wafer 44 after etching. .
448 70 5 五、發明說明（6) HDP etcher隨著製造廠商的不同會有不同的結構， 空艙内之内線圈48與外線圈50可以合併涘為一個單—上線 圈（top coil)。本發明電漿點火方法也可以運用在含有單 一上線圈的HDP etcher上。也就是對真空艙通入含有氬氣 與碳氟化合物之氣體’並且對上線圏施加電感(^功率為、 1000至1500瓦的電源〇因此一樣也能在半導體晶片表面形 成而分子層，以防止氬離子森擊所導致的光阻層變形，進 而使姓刻完後的半導艘晶片44上的輪廓與臨界尺寸都能得 到良好控制。 相較於習知的電漿點火方法，本發明之方法是以對真 空搶通入含有氬氣與碳氟化合物之氣想’並且適當地調整 對内線圈與外線圈提供之電感R F功率β 一方面使半導體晶 j上形成一層高分子層，另一方面使高分子層之沉積速率 星離子的森擊能量達到一種平衡，因此便保護光阻層的輪 廊’使姓刻完後的半導體晶片上的輪廓與臨界尺寸都能得 到良好控制。448 70 5 V. Description of the invention (6) HDP etcher will have different structures depending on the manufacturer. The inner coil 48 and the outer coil 50 in the cabin can be combined into a single top coil. The plasma ignition method of the present invention can also be applied to HDP etcher containing a single upper coil. That is, the vacuum chamber is filled with a gas containing argon and fluorocarbons, and an inductor (a power of 1000 to 1500 watts is applied to the upper line). Therefore, a molecular layer can be formed on the surface of the semiconductor wafer to prevent The deformation of the photoresist layer caused by the argon ion strike can further control the contour and critical size of the semi-conductor wafer 44 after the engraving. Compared with the conventional plasma ignition method, the invention The method is based on the idea that the gas containing argon and fluorocarbons is purged through the vacuum, and the inductor RF power β provided to the inner coil and the outer coil is adjusted appropriately. On the one hand, the deposition rate of the star layer ions on the polymer layer reaches a balance. Therefore, the photoresist layer's perimeter is protected so that the contour and critical size of the semiconductor wafer after the last name can be well controlled.