1267913 九、發明說明： • 【發明所屬之技術領域】 本發明係關於一種晶圓切割之方法’尤指一種於曰Γ~Ί 八日日圓 背面切割完後再於背面形成一膠膜用以固定已分離之晶粒 之方法。1267913 IX. Description of the invention: • Technical field to which the invention pertains The present invention relates to a method of wafer dicing, in particular, a method of forming a film on the back side of the yoke on the back of the eight-day yen. Method of separated grains.
【先前技術】 當積體電路於一晶圓上製作完成後，即會利用切割窜 程，如利用鑽石刀機械切割、雷射切割以及鑽石刀與雷射 混用之切割方式，將晶圓切割出複數個晶粒（die)，以便進 行後續之封裝製程，進而製作出可與電路板電連接之曰曰曰片 (chip) ° 習知之切割方式係由一晶圓上具有主動電路之主動 表面直接進行切割，然該方式使晶圓主動表面容易受切^ 所產生之粉塵（shards)或微粒（particulates)所污染，且該等 粉塵亦易附著於晶圓主動表面上且不容易以沖水方式清 除，進而影響晶圓主動表面之電性表現並降低產品良率 (yield rate)。更甚者，若所切割的晶圓主動表面更包含有感 光元件，則附著於晶圓彡動表面之粉塵將更造成產品的不 適用，降低產品的可靠度。 1267913[Prior Art] When the integrated circuit is fabricated on a wafer, the cutting process is performed, such as cutting with a diamond knife, laser cutting, and cutting with a diamond knife and a laser. A plurality of dies are formed for subsequent packaging processes to produce a chip that can be electrically connected to the circuit board. The conventional cutting method is performed by an active surface having an active circuit on a wafer. Cutting is performed in such a way that the active surface of the wafer is easily contaminated by shards or constituents, and the dust is also easily attached to the active surface of the wafer and is not easily flushed. Clearance, which in turn affects the electrical performance of the active surface of the wafer and reduces the yield rate of the product. What's more, if the active surface of the wafer to be cut further contains the photosensitive element, the dust attached to the floating surface of the wafer will be more unsuitable for the product and reduce the reliability of the product. 1267913
因此，為保護晶圓主動表面不受粉塵污染，現已發展 出由晶圓背面進行切割之方式，如美國專利第6,869,861號 所提供一由背面切割晶圓之方法。請參閱第1圖，其是先 提供一晶圓10,其具有一背面（圖未示）、一具有一主動表 面之正面12，以及複數條切割道14，用以定義複數個晶粒 16。接著利用一鑽孔器具由晶圓正面12穿至背面，形成複 數個相對於切割道14之複數個對準記號18，用以於切割 製程中，從背面提供對準記號18以供切割器具對準。接下 來於晶圓正面形成一膠膜，用以於切割製程中固定晶圓 10，並使切割後各分離之晶粒不至零散。最後再進行晶背 切割製程，然後分離晶圓與該膠膜，並進行撿晶。 然而，自晶圓背面切割，由於包含主動表面之晶圓正 面係朝下放置，若欲將主動表面朝上以進行後續製程，例 如包含感光元件之晶粒，則必須翻轉個別晶粒，以進行黏 晶（die attach)等後續製程，此舉造成製程上之冗長及不易， 嚴重影響產能(throughput)。 【發明内容】 因此本發明係於此提供一晶圓切割方法，以克服切割 晶圓背面方式所可能產生的問題。 根據本發明之所提供之晶圓切割方法，提供一晶圓， 1267913Therefore, in order to protect the active surface of the wafer from dust contamination, a method of cutting the wafer from the back side has been developed, as disclosed in U.S. Patent No. 6,869,861. Referring to Fig. 1, a wafer 10 is provided which has a back side (not shown), a front side 12 having an active surface, and a plurality of dicing streets 14 for defining a plurality of dies 16. Then, a plurality of alignment marks 18 are formed from the wafer front surface 12 to the back surface by using a drilling tool to form a plurality of alignment marks 18 relative to the dicing streets 14 for providing alignment marks 18 from the back side for the cutting tool pair during the cutting process. quasi. A film is formed on the front side of the wafer to fix the wafer 10 during the cutting process, and the separated grains are not scattered after the cutting. Finally, a crystal back cutting process is performed, and then the wafer and the film are separated and twinned. However, since the wafer is cut from the back side of the wafer, since the front surface of the wafer containing the active surface is placed face down, if the active surface is to be facing upward for subsequent processes, such as the grain containing the photosensitive element, the individual grains must be flipped for Subsequent processes such as die attach, which cause lengthy and difficult process, seriously affecting throughput. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a wafer dicing method that overcomes the problems that may arise in the manner in which the wafer is backed. According to the wafer cutting method provided by the present invention, a wafer is provided, 1267913
該晶圓之正面包含有一主動表面，且該主動表面定義有複 數條切割道（scribe lines)，用以界定該等晶粒之位置。並於 該晶圓之背面形成複數個對位記號(fiducial marks)，該等對 位記號皆對應於該等切割道。並於該晶圓之正面形成一第 一膠膜，之後進行一切割製程，將一切割器具對準該晶圓 背面之該等對位記.號，由該晶圓之背面切割該晶圓成複數 個晶粒，且各該晶粒係黏著於該'第一膠膜上。接下來，於 該晶圓之背面形成一第二膠膜，用以固定該等於切割製程 中分離之晶粒，最後分離該第一膠膜與該晶圓。 由於本發明係由晶圓之背面切割，因此切割製程中所 產生之粉塵，較不易黏附於晶圓之正面；加之以形成於該 晶圓正面之第一膠膜的保護，避免粉塵或顆粒黏附至晶圓 正面。另外，由於本發明更提供一第二膠膜於切割完該晶 圓後形成於該晶圓背面，並分離該第一膠膜與晶圓，因而 將該晶圓具有主動表面之正面暴露出來以供後續製程如黏 晶（die attach)之進行。 【實施方式】 請參考第2圖至第6圖，第2圖至第6圖為本發明之一 較佳實施例之示意圖。如第2圖所示，首先提供一晶圓20， 晶圓20包含有一晶圓正面22以及一晶圓背面24(圖未 示），且晶圓正面22具有一主動表面。接著對晶圓正面22 1267913 之主動表面進行至少一半導體製程，例如薄膜沉積、微影、 離子怖植、钱刻與研磨等製程，並藉由各製程之間相對應 的圖案轉移’以於晶圓正面22上形成複數條切割道(scribe lines)26，且切割道26係用以定義出複數個晶粒28之位置。 如第3圖所示，待晶圓2〇完崴所需之各式半導體製程 之後，接下來，再於晶圓背面24利用雷射標記(iaser making) 或飯刻方法形成複數個定位記號(fiducial marks) 30，且定 位$遽30係對應於晶圓JL面22之切割道26。另外，亦可 於曰日圓20邊緣切割出相對於切割道26之參考邊(reference cut)作為疋位㊂己號4〇，如第4圖所示。然本發明於晶圓背 面24形成定位記號30之方法並不侷限於本實施例中所述 之類型。 隨後請參考第5圖，於晶圓正面22形成一第一膠膜 50 ’例如一紫外線膠(UV tape)或藍膠(blue tape)，用以於後 續之切割製程中固定各分離之晶粒28。接下來，請參考第 6圖利用一切割器具60由晶圓背面24進行一切割製程。 並於進行切割之前，先執行一定位步驟，以使切割器具50 對準晶圓背面24之對位記號30。之後進行切割製程，將 晶圓20自晶圓背面24切割成分離之各晶粒28，且各晶粒 28之正面仍黏著於第一膠膜50而不至零散。其中，在進 仃切割製程時或完成切割製程之後，可視實際製程狀況或 1267913 * · 潔淨需求，進行至少一清洗步驟，用以清洗晶圓20並移除 ~ 該切割製程所產生之粉塵。 值得注意的是，由於本發明係由晶圓背面24進行切 割製程，因此可有效防止晶圓正面22受到切割產生之粉塵 附著而造成之污染情形的發生，此外，第一膠膜50更有保 護晶圓正面22不受切割粉塵污染的功能。The front side of the wafer includes an active surface, and the active surface defines a plurality of scribe lines for defining the locations of the dies. A plurality of fiducial marks are formed on the back side of the wafer, and the alignment marks correspond to the dicing tracks. Forming a first film on the front side of the wafer, and then performing a cutting process to align a cutting tool with the alignment marks on the back side of the wafer, and cutting the wafer into a plurality of wafers from the back side of the wafer Each of the crystal grains is adhered to the 'first film. Next, a second film is formed on the back surface of the wafer for fixing the separated die equal to the cutting process, and finally separating the first film and the wafer. Since the present invention is cut from the back side of the wafer, the dust generated in the cutting process is less likely to adhere to the front side of the wafer; and the first film formed on the front side of the wafer is protected from dust or particle adhesion. To the front of the wafer. In addition, the present invention further provides that a second film is formed on the back surface of the wafer after the wafer is cut, and the first film and the wafer are separated, thereby exposing the front surface of the active surface of the wafer to For subsequent processes such as die attach. [Embodiment] Please refer to Figs. 2 to 6 and Fig. 2 to Fig. 6 are schematic views showing a preferred embodiment of the present invention. As shown in FIG. 2, a wafer 20 is first provided. The wafer 20 includes a wafer front side 22 and a wafer back side 24 (not shown), and the wafer front side 22 has an active surface. Then, the active surface of the wafer front surface 22 1267913 is subjected to at least one semiconductor process, such as thin film deposition, lithography, ion implantation, money etching and polishing, and transferred by a corresponding pattern between the processes. A plurality of scribe lines 26 are formed on the circular front surface 22, and the scribe lines 26 are used to define the positions of the plurality of dies 28. As shown in FIG. 3, after various semiconductor processes required for the wafer 2 to be completed, a plurality of positioning marks are formed on the wafer back surface 24 by using an iaser making or a rice carving method ( Fiducial marks 30, and the position $遽30 corresponds to the scribe line 26 of the wafer JL face 22. Alternatively, the reference cut relative to the scribe line 26 may be cut at the edge of the 曰 yen 20 as the 三三三号4〇, as shown in Fig. 4. However, the method of the present invention for forming the alignment mark 30 on the wafer back surface 24 is not limited to the type described in the embodiment. Then, referring to FIG. 5, a first adhesive film 50' such as a UV tape or a blue tape is formed on the front surface 22 of the wafer for fixing the separated crystal grains in the subsequent cutting process. 28. Next, please refer to Fig. 6 for a cutting process from the wafer back side 24 using a cutting tool 60. And prior to cutting, a positioning step is performed to align the cutting tool 50 with the alignment mark 30 on the back side 24 of the wafer. Then, the dicing process is performed to cut the wafer 20 from the wafer back surface 24 into the separated dies 28, and the front side of each of the dies 28 is still adhered to the first film 50 without being scattered. Wherein, during the cutting process or after the cutting process is completed, at least one cleaning step is performed to clean the wafer 20 and remove the dust generated by the cutting process, depending on the actual process conditions or 1267913*. It should be noted that since the present invention performs the cutting process from the wafer back surface 24, the wafer front surface 22 can be effectively prevented from being contaminated by the dust generated by the cutting, and the first film 50 is more protected. The wafer front side 22 is not contaminated by cutting dust.
請參考第7圖，接下來對·晶圓正面22之第一膠膜50 照射紫外光，用以去除第一膠膜50之黏性。然後於晶圓背 面24形成一第二膠膜70，如一紫外線膠或藍膠。其中， 第二膠膜70之材質特性可與第一膠膜50相同，亦可為不 同材質之膠膜，例如第一、第二膠膜均為光分解型膠膜或 熱分離膠膜，或者是一膠膜為光分解型膠膜，而另一膠膜 為熱分離膠膜。之後翻轉蟲圓20，使晶圓正面22朝上， 並分離晶圓20與第一膠膜50，如第8圖所示。隨後對第 二膠膜70照射紫外光，以去除第二膠膜70之黏性，而進 行後續如黏晶、撿晶等製程。 綜合上述說明，本發明所提供之方法，係於具有主動 電路之晶圓正面形成一第一膠膜，並由晶圓背面進行切 割，其中該第一膠膜不僅用以固定各切割後分離之晶粒， 並可保護晶粒正面不受切割所產生之粉塵所污染。在完成 1267913 晶背切割製程之後，先照射紫外光，以去除第一膠膜之黏 性，再於該晶圓背面上貼覆一第二膠膜；此外，亦可於該 晶圓背面先貼覆於一第二‘膠膜，再照射紫外光以去除該第 一膠膜。最後翻轉該晶圓以使晶圓正面朝上，進行後續製 程如撿晶及黏晶，以此避免翻轉個別晶粒之費時步驟。Referring to FIG. 7, the first film 50 of the wafer front surface 22 is irradiated with ultraviolet light to remove the viscosity of the first film 50. A second film 70, such as a UV or blue glue, is then formed on the backside 24 of the wafer. The material property of the second adhesive film 70 may be the same as that of the first adhesive film 50, or may be a film of different materials. For example, the first and second adhesive films are all photo-decomposable adhesive films or thermal separation adhesive films, or One film is a photo-decomposable film, and the other film is a thermal separation film. The wafer circle 20 is then flipped so that the wafer front side 22 faces upward, and the wafer 20 and the first film 50 are separated, as shown in FIG. Subsequently, the second adhesive film 70 is irradiated with ultraviolet light to remove the viscosity of the second adhesive film 70, and subsequent processes such as die bonding and twinning are performed. In summary, the method provided by the present invention is to form a first film on the front surface of a wafer having an active circuit and cut it from the back side of the wafer, wherein the first film is not only used to fix the separation after cutting. The grain, and can protect the front side of the grain from the dust generated by cutting. After completing the 1267913 crystal back cutting process, ultraviolet light is irradiated to remove the adhesiveness of the first film, and a second film is attached on the back surface of the wafer; in addition, the back surface of the wafer may be pasted first. Covering a second 'film, and then irradiating ultraviolet light to remove the first film. Finally, the wafer is flipped so that the wafer faces up, and subsequent processes such as twinning and die bonding are performed to avoid time consuming steps of flipping individual dies.
以上所述僅為本發明之較佳實施例，凡依本發明申請 專利範圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖為習知晶圓背面切割方式之晶圓示意圖。 第2至第3圖為本發明所提供之晶圓切割方式之上視圖。 第4圖為本發明所提供之另一種定位記號之示意圖 第5至第8圖為本發明所提供之晶圓切割方式之剖面圖。 【主要元件符號說明】 10 晶圓 1.2 晶圓正面 14 切割道 16 晶粒 18 對準記號 20 晶圓 22 晶圓正面 24 晶圓背面 26 切割道 28 晶粒 30、40 定位記號 50 第一膠膜 60 切割器具 70 第二膠膜The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention. [Simplified Schematic Description] Fig. 1 is a schematic diagram of a wafer on the back side of a conventional wafer. 2 to 3 are top views of the wafer cutting method provided by the present invention. Fig. 4 is a schematic view showing another positioning mark provided by the present invention. Figs. 5 to 8 are cross-sectional views showing a wafer cutting method provided by the present invention. [Main component symbol description] 10 Wafer 1.2 Wafer front 14 Cutting lane 16 Grain 18 Alignment mark 20 Wafer 22 Wafer front 24 Wafer back 26 Cutting lane 28 Grain 30, 40 Positioning mark 50 First film 60 cutting device 70 second film