1254345 14381twf.doc/g 九、發明說明： 【發明所屬之技術領域】 、本餐明疋有關於一種低介電常數(1〇w#材料層的形 成方法，且特別是有關於-種減少低介電常數材料層之微 粒數目的方法。 & 【先前技術】1254345 14381twf.doc/g Nine, the invention description: [Technical field to which the invention belongs], this meal has a low dielectric constant (1〇w# material layer formation method, and especially related to - reduction A method of the number of particles of a dielectric constant material layer. & [Prior Art]
Ik著起大型積體電路(ultra_Large Scale Integ加丨⑽， 籲 ULSI)的元件尺寸持續縮小，由多層金屬内連線所導致的 RC 延遲(ReSistance-Capadtance 旧町)不但會限 速操作的能力:也會提高功雜損，而導致晶片溫度上升同 而使用低介電常數材料作為？層金屬0連線間的介電層能 夠有效縮短RC延遲的時間。 現今有許多低介電常數材料係以電漿增強化學汽相 >儿積法(PECVD)來形成，包括一種稱作hard_c〇RAl的 材料，其係以四曱基環四矽氧烷 (tetramethylcyclotetra-siloxane，TMCTS)為反應氣體。但 ® 是，在低介電常數材料層達預定厚度而將TMCTS氣體源 關閉之後，殘餘的TMCTS氣體會再繼續進行沉積反應， 而產生微粒缺陷。如此在量產之前，即須花費額外的時間 來處理製程線上微粒的問題，使得產品交期受到影響。 習知有一種方法可以改善低介電常數材料層沉積時 產生微粒缺陷的問題，其係在反應氣體源關閉之後，在一 段延遲時間（delay time)内繼續供應低頻電源(lf power)及 高頻電源(HF power)，但降低二者的功率。如此即可以減 5 1254345 14381twf.doc/g 少微粒缺陷的數目。 圖1為使用上述方法沉積而得之低介電常數 士視圖。如圖m示，雖然該方法可以減少殘存氣體= == = :數目，但是所產生的單位面積微粒數‘ 退疋同達9697顆，其將對後續的製程造成影響。 【發明内容】 曰 本發明的目的就是在提供_種減少低介電 層之微粒數目的方法，以增進成膜品質並提高生產效二 在本發明之減少低介電常數材料層之微粒數^ 法中，所謂的低介電常數材料層係以電聚增強化學氣 積法所形成者，其沉積過程係使用—反應氣體、 體、一高頻電源及一低頻電源。此方法則包括： 常數材料層形紐，關該反應氣體及低頻鶴，二 延遲時間内繼續供應清除氣體。 依妝本發明的一實施例，在上述延遲時間内，高 源之功率等於或低於沈積低介電常數材料層時之值了另二 種作法則係在延遲時間内完全關閉高頻電源，並令壓力p 低’其同樣有減少微粒數的效果。 牛 另外，依照本發明的較佳實施例，上述之反應氣 括四甲基環四石夕氧烧。 、由於採用上述本發明之方法即可減少低介電常數 料層的微粒數目，因此本發明可增進成膜品質並提高生產 為讓本發明之上述和其他目的、特徵和優點能更明顯 6 1254345 14381twf.doc/g 易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說 明如下。 【實施方式】 在此較佳實施例中，所使用的反應氣體為四曱基環四 石夕氧烧(TMCTS)，其例如是由一液態系統提供之液態 TMCTS氣化而得者，且其在正常沉積期間的流量通常為 1.5〜6.5sccm 〇 另外’所使用的清除氣體例如是二氧化碳。在正常沉 積期間内’ ^一氧化$厌清除氣體的流量通常為3〇〇〇至12000 seem，高頻電源的功率通常為700〜1500W，且低頻電源的 功率通常約在800W以下，其頻率則通常為35〇〜45〇Hz。 另外，電漿增強化學汽相沉積反應的操作溫度通常是 350〜450QC，其操作壓力則通常是2.5〜5Torr。 然後，在預疋居度的低介電常數材料層形成後，關閉 TMCTS氣體源及低頻電源，並在一延遲時間内繼續供應 清除氣體。此延遲時間例如是1至5秒，且在延遲時間^ 高頻電源之功率在1500W以下。另一作法則是在延遲時間 内完全_高㈣源，並令壓力降低，其亦可減少微粒之 產生。此外’在延遲時間内，二氧化碳清除氣體的流 如是6_至1G_ sccm，其係用以清除所產生的微粒。 圖2為使用本發明較佳實施例之方法所得之低介 數材料層的上視圖。如圖2所示，可以看出本發明之方 可有效減少齡缺陷的數目’所以在卿成的低介 材料層上只出現稀疏的9顆微粒。 7 1254345 14381 twf.doc/g M丄W您，由於採用本發明之方法 粒數目，本發明可增遲 雖然本發明已以較佳實 ，定二發明’任_此技藝者，：°離 r視後附之申;專本發明之保護 【圖式簡單說明】 之上=係為使知方法進行低介電常歸㈣沉積後 ，2係為本發明—較佳#施例進行低介電常數材料層 "L積後之上視圖。 【主要元件符號說明】Ik is holding up a large integrated circuit (ultra_Large Scale Integ (10), ULSI), and the component size continues to shrink. The RC delay caused by the multi-layer metal interconnect (ReSistance-Capadtance) will not only limit the speed: Will it also increase the work and damage, and cause the wafer temperature to rise while using a low dielectric constant material? The dielectric layer between the layer metal 0 lines can effectively shorten the RC delay time. Many low dielectric constant materials are now formed by plasma enhanced chemical vapor phase > PECVD, including a material called hard_c〇RAl, which is tetramethylcyclotetra -siloxane, TMCTS) is a reactive gas. However, ® is, after the low dielectric constant material layer reaches a predetermined thickness and the TMCTS gas source is turned off, the residual TMCTS gas will continue to carry out the deposition reaction to generate particulate defects. So before the mass production, it takes extra time to deal with the problem of particles on the process line, so that the product delivery time is affected. There is a known method for improving the problem of particle defects in the deposition of a low dielectric constant material layer, which continues to supply a low frequency power supply (LF power) and a high frequency for a delay time after the reaction gas source is turned off. Power (HF power), but reduce the power of both. This can reduce the number of small particle defects by 5 1254345 14381twf.doc / g. Fig. 1 is a view showing a low dielectric constant deposited by the above method. As shown in Fig. m, although this method can reduce the number of residual gases = == = :, the number of particles per unit area produced is </ s>, which will affect the subsequent processes. SUMMARY OF THE INVENTION The object of the present invention is to provide a method for reducing the number of particles in a low dielectric layer to improve film formation quality and to improve production efficiency. The number of particles in the reduced low dielectric constant material layer of the present invention is ^ In the method, the so-called low dielectric constant material layer is formed by electropolymerization enhanced chemical gas accumulation method, and the deposition process uses a reaction gas, a body, a high frequency power source and a low frequency power source. The method comprises: a constant material layer shape button, the reaction gas and the low frequency crane are closed, and the purge gas is continuously supplied during the delay time. According to an embodiment of the present invention, during the delay time, the power of the high source is equal to or lower than the value of depositing the low dielectric constant material layer, and the other two methods completely turn off the high frequency power supply within the delay time. And let the pressure p be low, which also has the effect of reducing the number of particles. Further, in accordance with a preferred embodiment of the present invention, the above reaction gas comprises tetramethylcyclotetrazepine. Since the method of the present invention can reduce the number of particles of the low dielectric constant layer, the present invention can improve the film forming quality and improve production so that the above and other objects, features and advantages of the present invention can be made more apparent. 14381 twf.doc / g is easy to understand, the preferred embodiments are described below, and in conjunction with the drawings, a detailed description is as follows. [Embodiment] In the preferred embodiment, the reaction gas used is tetrakisylcyclotetracycline (TMCTS), which is obtained, for example, by gasification of liquid TMCTS supplied by a liquid system, and The flow rate during normal deposition is usually 1.5 to 6.5 sccm. In addition, the purge gas used is, for example, carbon dioxide. During the normal deposition period, the flow rate of the gas is usually from 3 〇〇〇 to 12,000 seem, the power of the high-frequency power source is usually 700 to 1500 W, and the power of the low-frequency power source is usually about 800 W or less, and the frequency is Usually 35〇~45〇Hz. In addition, the operating temperature of the plasma enhanced chemical vapor deposition reaction is usually 350 to 450 QC, and the operating pressure is usually 2.5 to 5 Torr. Then, after the formation of the pre-poplination low dielectric constant material layer, the TMCTS gas source and the low frequency power source are turned off, and the purge gas is continuously supplied for a delay time. This delay time is, for example, 1 to 5 seconds, and at the delay time ^ the power of the high frequency power supply is below 1500W. Another rule is to completely _ high (four) sources within the delay time and to reduce the pressure, which also reduces the generation of particles. Further, during the delay time, the flow of the carbon dioxide scavenging gas is, for example, 6_ to 1G_sccm, which is used to remove the generated particles. Figure 2 is a top plan view of a low dielectric material layer obtained using the method of the preferred embodiment of the present invention. As shown in Fig. 2, it can be seen that the method of the present invention can effectively reduce the number of age defects. Therefore, only a sparse 9 particles appear on the low dielectric layer of Qingcheng. 7 1254345 14381 twf.doc/g M丄W, because the number of particles of the method of the present invention is used, the present invention can be delayed. Although the present invention has been improved, the invention is as follows: Apparently attached to the application; the protection of the invention [simplified description of the diagram] Above = is to make the method of low dielectric constant (4) deposition, 2 is the invention - better # example for low dielectric Constant material layer "L product after the upper view. [Main component symbol description]