201241996 六、發明說明： 【發明所屬之技術領域】 本發明是揭露一種影像感測器，由指一種具有截角之彩 色滤光片的影像感測器。 【先前技術】 互補式金氧半導體電晶體影像感測器（CMOS image sensor, CIS)和載子偶合裝置（charge-coupled devices, CCDs) 都是習知技術中常用來將光轉換為電子訊號的光學電路元 件，兩者的應用範圍皆很廣泛，包括有掃描器、攝影機以及 照相機等等，但是因為載子偶合裝置受限於價位以及製程整 合的問題，所以目前市面上以互補式金氧半導體電晶體影像 感測器較為普及。 由於互補式金氧半導體電晶體影像感測器是以傳統的 半導體製程製作，因此可以大幅減少所需成本及元件尺寸， 而其應用範圍包括個人電腦相機以及數位相機等數位電子 商品，目前互補式金氧半導體電晶體影像感測器大致分為線 型、面型兩種，而線型互補式金氧半導體電晶體影像感測器 以應用在掃瞄器等產品為主，面型互補式金氧半導體電晶體 影像感測器則以應用在數位相機等產品為主。 201241996 然而’隨著現今影像感測器解析度提高（small pitch)，感 測元件朝小尺寸與3D的方向發展，元件設計挑戰光學物理 極限’進入影像感測器的主光線角（chief-ray angle)也跟著提 升，使周邊暗角（vignetting)的問題日趨嚴重。因此如何讓光 線更容易由微透鏡結構進入影像感測器並解決上述問題，而 不會衍生其它問題，即為現今製作影像感測器的重要課題。 【發明内容】 因此本發明是揭露一種影像感測器以解決上述問題。 依據本發明之較佳實施例，是揭露一種影像感測器，其 包含一基底 '至少一彩色濾光片以及一微透鏡。其中基底上 具有至少一保護層，至少一彩色濾光片是設於保護層上，且 彩色濾光片具有截角角錐狀的表面。微透鏡則設於彩色濾光 片表面。 【實施方式】 請參考第1圖至第6圖，第1圖至第6圖為本發明第一 較佳實施例製作影像感測器之方法及結構示意圖。如第1圖 所示，本發明首先提供一基底100，且基底100上具有一介 電層102。其中，基底1〇〇較佳為一半導體基底，但不限制 為一矽晶圓（wafer)或一矽覆絕緣(SOI)等之基底。基底1〇〇 可包含有複數個感光性的結構96，例如感光二極體 201241996 (photodiode)等，用來接收外部的光線並感測光照的強度，且 該等感光性的結構另電連接有重置電晶體、電流汲取元件或 列選擇開關等之CMOS電晶體（未顯示），以及複數個絕緣物 98，例如淺溝隔離（shallow trench isolation，STI)或局部石夕氧 化絕緣層（local oxidation of silicon isolation layer, LOCOS)， 用以避免該等感光性的結構、MOS電晶體與其他元件相接 觸而發生短路。此外，介電層102可包含有一層間介電（inter layer dielectric, ILD)層 103、一金屬間介電（inter metal dielectric，IMD)層105、一平坦化層107、以及一由氮化石夕 等材料所構成的保護層108。金屬間介電層1〇5與平坦化層 107則形成有複數個金屬層104與金屬層1〇6等之多重金屬 内連線(multilevel interconnects)層，作為該等感光性之結 構、MOS電晶體與其他元件之電路連結用，且其皆形成於 各淺溝隔離或CMOS電晶體的上方，除了避免遮蔽各感光性 之結構’又可使入射光（未顯示）射入時得以聚集於感光性 之結構，而不發生散射，造成訊號干擾(cr〇ss taik)。 接著如第2圖所示’形成一介電材料（圖未示）在保護層 108上，並進行一圖案轉移製程，例如進行一次或一次以上 的蝕刻製程去除部分介電材料，以於保護層1〇8上形成複數 個具有截角的内透鏡(inner lens)11〇。在本實施例中，内透鏡 • 110較佳由二氧化矽或氮化矽所構成，且選擇之材料可與保 護層108相同或不同。 5 201241996 隨後依序形成複數個彩色濾光層（圖未示）於保護層ι〇8 上，並搭配進行多次曝光與顯影製程，以於保護層1〇8及内 透鏡110上形成複數個彩色滤光片112，且㈣色遽光片112 較佳對應基底100表面的各感光二極體。其中，彩色濾光片 ⑴可包含紅色滤光片、綠色濾光片、藍色瀘光片或其^顏 色的濾光片。需注意的是’本實施例所揭露的内透鏡ιι〇為 一選擇性結構。亦即，本發明又可視製㈣求省略上述製作 内透鏡m的製程而直接在保護層1〇8上形成上述彩色濟光 片⑴，此實施例也屬本發明所涵蓋的範圍。 然设如第 彩色遽光片Π2表面，用以當^ 旦層（圖未示)於 方式去除各彩色編112二:=並選擇以曝_ 進而形成複數個具有截角角錐狀表面的彩面最 濾一程來完成具有截角的彩色 飯刻氣體來去除各彩色例如_氧氣等 錐，此製程手段也屬本發明所涵蓋=以形成截角角 具有截角之測色濾光片 請繼續參照第5圖，其為本發明 6 201241996 與習知彩色濾光片之收光面積比較圖。如圖中所示，習知彩 色濾光片通常為一矩形形狀，如圖中的左邊部分，或一圓形 形狀，如圖中的右邊部分。相較於習知彩色濾光片僅藉由一 平坦狀頂表面122或圓弧型頂表面124來吸收光線，本發明 依據上述製程所形成具有截角角錐之彩色濾光片則藉由一 頂表面及四個斜面來吸收光線。若以矩形的邊長或圓形的直 # 2.2微米為例來計算彩色遽光片的收光面積，在相同的厚 度下’習知矩形彩色濾光片的整體收光面積約略為4 84平方 微米而圓形彩色遽光片的整體收光面積則約略為7.60平方 微米。本發明整個彩色濾、光片的收光面積，即頂表面126的 ㈣加上四周斜面128的面積則約略8 815平方微米。由此 可見本發明所製作出具有戴角或約略金字塔狀的彩色減光 片可㈣知矩形彩色濾、光片多出82%的收光面積，且比^知 圓形才> 色濾光片多出16%的收光面積。 上述用來對彩色攄光片112進㈣案轉移製程的 限於任何形狀。請參照第6圖，其綠示以不同 形狀之_化平坦層當作遮罩來形成彩色濾光片之示音 ::圖:’若以矩型的圖案化平坦層來對彩色遽光片 =订圖案轉移製程，則所形成之彩色濾、光片m的頂表 現矩型。反之’若以圓形的圓案化平坦層對彩色滹光 片112進行圖⑽移製程， 色慮先 表面便會呈現圓形。 化成之知色慮光片m的頂 201241996 、，隨後如第7圖所示，可於形成具有截角角錐表面的彩色 二、光片114之後形成一由壓克力（acryiate materiai)材料所構 成的聚合層（圖未示）並覆蓋彩色濾光片114。接著進行一曝 光與顯影製程，將聚合層曝出對應各彩色濾光片114的形 狀’並對聚合層搭配進行一烘烤製程，以於彩色渡光片叫 上形成複數個半圓球型的微透鏡116。至此即完成本發明第 一實施例之一影像感測器的製作。本實施例雖於形成具有戴 角角錐表面的彩色滤光片114後直接形成微透鏡116，但不 侷限於此，又可在形成微透鏡116之前選擇性再覆蓋另—平 坦層（圖未示）在彩色濾光片114表面，此實施例也屬本發 所涵蓋的範圍。 請接著參照第8圖，其為本發明另一實施例之影像感測 器之示意圖。如圖中所示，接續第3圖之製程完成具有截角 的彩色濾光片114之後，本發明可依據製程需求將_不需進 行烘烤(Non-Reflow Type)的感光材料覆蓋在彩色濾光片工μ 表面，然後對感光材料進行一曝光顯影製程，並同時藉由調 整曝光的位置與曝光量使感光材料形成如圖中具有戴角角 錐表面的微透鏡118。 如第9圖所示，本發明可利用具有角錐表面的彩色濾光 片114及内透鏡110來增加光線的入射面積，並同時藉由粗 8 201241996 糙表面來減少光線的反射，使光線更容易進入影像感測器。 此設計除了有利於主光線角（chief-ray angle)的提升之外，又 可改善周邊暗角（vignetting)與影像晝面亮度不均的問題。 另外，如第10圖所示，本發明具有角錐表面之内透鏡、 彩色濾光片及微透鏡結構又可應用至一背照式（back-side illuminated，BSI)CMOS影像感測器130。其中，背照式CMOS 影像感測器130主要包含一載板132、一矽基底134以及一 金屬内連線層136設於載板132與矽基底134之間，而本發 明所揭露之内透鏡、彩色濾光片及微透鏡等結構則較佳設於 矽基底134相對於金屬内連線層136側之另一側表面。依此 設計，本發明除了可保有背照式CMOS影像感測器本身具有 更佳感光度與色彩呈現等優點外又可同時藉由截角角錐狀 的設計來提升影像感測器的整體效能。 綜上所述，本發明主要在製作彩色濾光片的時候先對彩 色濾光片進行一圖案轉移製程’例如利用曝光顯影或蝕刻的 方式去除部分彩色濾光片，以製作出具有截角角錐表面的彩 色濾光片。藉由截角角錐表面的形成’本發明可大幅提昇彩 色濾光片吸收光線的表面積，使更多光線在影像感測器朝小 尺寸發展的情况下仍能順利由彩色濾光片進入感光二極 體，進而改善周邊暗角的問題。另外’除了對彩色濾光片本 身形成截角角錐表面，本發明又可視產品的需求對保護層上 201241996 的内透鏡及彩色濾光片上方的微透鏡同樣形成截角角錐表 面，以製作出不同態樣但同樣具有較大吸光表面積的影像感 測器。 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圖至第7圖為本發明第一較佳實施例製作影像感測器之 方法及結構示意圖。 第8圖為本發明另一實施例之影像感測器之示意圖。 第9圖為本發明利用具有角錐表面的彩色濾光片及微透鏡來 增加光線入射面積之示意圖。 第10圖為本發明之一背照式CMOS影像感測器之示意圖。 【主要元件符號說明】 96 結構 98 絕緣物 100 基底 102 介電層 103 層間介電層 104 金屬層 105 金屬間介電層 106 金屬層 107 平坦化層 108 保護層 110 内透鏡 112 彩色濾光片 114 彩色濾光片 116 微透鏡 201241996 118 微透鏡 122 頂表面 124 頂表面 126 頂表面 128 斜面 130 背照式CMOS影像感 132 載板 測器 134 矽基底 136 金屬内連線層201241996 VI. Description of the Invention: [Technical Field] The present invention discloses an image sensor which is an image sensor having a color filter having a truncated angle. [Prior Art] Complementary CMOS image sensor (CIS) and charge-coupled devices (CCDs) are commonly used in conventional techniques to convert light into electronic signals. Optical circuit components, both of which cover a wide range of applications, including scanners, cameras, and cameras, but because of the limited price and process integration of carrier coupling devices, complementary MOS devices are currently available on the market. Transistor image sensors are more popular. Since the complementary MOS transistor image sensor is fabricated in a conventional semiconductor process, it can significantly reduce the cost and component size, and its application range includes digital electronic products such as personal computer cameras and digital cameras. The MOS transistor image sensor is roughly classified into a line type and a surface type, and the line type complementary MOS transistor image sensor is mainly applied to a scanner and the like, and the surface type complementary MOS semiconductor is used. The transistor image sensor is mainly applied to products such as digital cameras. 201241996 However, with the current image sensor's small pitch, the sensing element is moving toward a small size and 3D direction, and the component design challenges the optical physical limit 'to enter the image sensor's chief ray angle (chief-ray) The angle is also increased, making the problem of vignetting worse. Therefore, how to make the light line easier to enter the image sensor from the microlens structure and solve the above problem without deriving other problems is an important issue for making image sensors today. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to an image sensor to solve the above problems. In accordance with a preferred embodiment of the present invention, an image sensor is disclosed that includes a substrate 'at least one color filter and a microlens. Wherein the substrate has at least one protective layer, at least one color filter is disposed on the protective layer, and the color filter has a truncated pyramidal surface. The microlens is placed on the surface of the color filter. [Embodiment] Please refer to FIG. 1 to FIG. 6 . FIG. 1 to FIG. 6 are schematic diagrams showing a method and a structure for fabricating an image sensor according to a first preferred embodiment of the present invention. As shown in FIG. 1, the present invention first provides a substrate 100 having a dielectric layer 102 thereon. The substrate 1 is preferably a semiconductor substrate, but is not limited to a substrate such as a wafer or a SOI. The substrate 1 may include a plurality of photosensitive structures 96, such as a photodiode 201241996 (photodiode), etc., for receiving external light and sensing the intensity of the light, and the photosensitive structures are electrically connected A CMOS transistor (not shown) for resetting a transistor, a current sinking element or a column select switch, and a plurality of insulators 98, such as shallow trench isolation (STI) or local oxidized insulating layer (local oxidation) The silicon isolation layer (LOCOS) is used to avoid short-circuiting of the photosensitive structure and the MOS transistor in contact with other elements. In addition, the dielectric layer 102 may include an inter-layer dielectric (ILD) layer 103, an inter-metal dielectric (IMD) layer 105, a planarization layer 107, and a nitride layer. A protective layer 108 of material. The inter-metal dielectric layer 1〇5 and the planarization layer 107 are formed with a plurality of metal intercalation layers such as a metal layer 104 and a metal layer 1〇6, and the MOS is used as the photosensitive structure. The crystal is connected to the circuit of other components, and is formed on each shallow trench isolation or CMOS transistor, in addition to avoiding shielding the photosensitive structure' and allowing the incident light (not shown) to be incident on the photosensitive Sexual structure without scattering, causing signal interference (cr〇ss taik). Then, as shown in FIG. 2, a dielectric material (not shown) is formed on the protective layer 108, and a pattern transfer process is performed, for example, one or more etching processes are performed to remove a portion of the dielectric material to protect the protective layer. A plurality of inner lenses 11 具有 having a truncated angle are formed on 1〇8. In the present embodiment, the inner lens 110 is preferably composed of hafnium oxide or tantalum nitride, and the material selected may be the same as or different from the protective layer 108. 5 201241996 Subsequently, a plurality of color filter layers (not shown) are sequentially formed on the protective layer ι8, and are subjected to multiple exposure and development processes to form a plurality of layers on the protective layer 1〇8 and the inner lens 110. The color filter 112, and the (four) color filter 112 preferably corresponds to each of the photosensitive diodes on the surface of the substrate 100. The color filter (1) may include a red filter, a green filter, a blue calender, or a color filter. It should be noted that the inner lens ιι disclosed in the embodiment is a selective structure. That is, the present invention can also visually (4) omit the above-described process for fabricating the inner lens m, and directly form the above-mentioned color light-receiving sheet (1) on the protective layer 1A, and this embodiment is also within the scope of the present invention. However, the surface of the color light-receiving sheet Π 2 is used to remove the color code 112 2 from the layer (not shown) and select to expose a plurality of colored surfaces having a truncated pyramidal surface. The most filtering process is to complete the color cooking gas with truncated angle to remove the cones of various colors such as _ oxygen, etc., and the process method is also covered by the present invention = the color measuring filter having a truncated angle to form a truncated angle, please continue Referring to Fig. 5, it is a comparison diagram of the light-receiving area of the conventional color filter of the invention 6 201241996. As shown in the figure, the conventional color filter is usually in the shape of a rectangle, as shown in the left part of the figure, or a circular shape, as shown in the right part of the figure. Compared with the conventional color filter, only a flat top surface 122 or a circular top surface 124 absorbs light. According to the above process, the color filter having a truncated pyramid is formed by the above process. The surface and four bevels absorb light. If the rectangular length or the circular straight #2.2 micron is taken as an example to calculate the light-receiving area of the color calender, the overall light-receiving area of the conventional rectangular color filter is about 4 84 squares at the same thickness. The overall light-receiving area of the micron and circular color calender is approximately 7.60 square microns. The light-receiving area of the entire color filter and light sheet of the present invention, i.e., the area of the top surface 126 plus the four-sided bevel 128 is approximately 8,815 square microns. It can be seen that the color dimming sheet having the wearing angle or the approximate pyramid shape can be produced by the invention. (4) The rectangular color filter is known, and the light collecting area is 82% more than the light collecting area, and the color is lighter than the color filter. The film has 16% more light-receiving area. The above-described transfer process for the color grading sheet 112 into (4) is limited to any shape. Please refer to Fig. 6, which shows the sound of the color filter with a different shape of the flattening layer as a mask:: Figure: If the rectangular layer is patterned by a rectangular pattern = The pattern transfer process is performed, and the color filter formed and the top of the light sheet m exhibit a rectangular shape. On the other hand, if the circular flattening layer is used to perform the process of drawing (10) on the color light-emitting sheet 112, the surface will be rounded. The top of the formed color light-receiving sheet m 201241996, and then as shown in Fig. 7, can be formed by forming a color two-light sheet 114 having a truncated pyramid surface to form an acried materiai material. The polymeric layer (not shown) covers the color filter 114. Then, an exposure and development process is performed, and the polymer layer is exposed to the shape of each color filter 114 and a baking process is performed on the polymer layer to form a plurality of semi-spherical micro-shaped micro-patterns. Lens 116. Thus, the production of an image sensor of the first embodiment of the present invention has been completed. In this embodiment, although the microlens 116 is directly formed after forming the color filter 114 having the corner pyramid surface, the present invention is not limited thereto, and the other flat layer may be selectively covered before the microlens 116 is formed (not shown). On the surface of the color filter 114, this embodiment is also within the scope of the present invention. Please refer to Fig. 8, which is a schematic diagram of an image sensor according to another embodiment of the present invention. As shown in the figure, after the process of FIG. 3 is completed to complete the color filter 114 having a truncated angle, the present invention can cover the non-reflow type photosensitive material in the color filter according to the process requirements. The surface of the film is then subjected to an exposure and development process, and at the same time, the photosensitive material is formed into a microlens 118 having a pyramidal surface as shown in the figure by adjusting the position and exposure of the exposure. As shown in FIG. 9, the present invention can utilize the color filter 114 having the pyramid surface and the inner lens 110 to increase the incident area of the light, and at the same time reduce the reflection of the light by the rough surface of the 201241996, making the light easier. Enter the image sensor. In addition to facilitating the improvement of the chief-ray angle, this design can also improve the problem of uneven vignetting and uneven brightness of the image. In addition, as shown in FIG. 10, the inner lens, the color filter and the microlens structure having the pyramid surface of the present invention can be applied to a back-side illuminated (BSI) CMOS image sensor 130. The back-illuminated CMOS image sensor 130 mainly includes a carrier 132, a germanium substrate 134, and a metal interconnect layer 136 disposed between the carrier 132 and the germanium substrate 134, and the inner lens disclosed in the present invention. The structure of the color filter and the microlens is preferably disposed on the other side surface of the crucible base 134 with respect to the side of the metal inner wiring layer 136. According to the design, the present invention can not only maintain the advantages of sensitivity and color rendering of the back-illuminated CMOS image sensor itself, but also enhance the overall performance of the image sensor by the truncated pyramid shape design. In summary, the present invention mainly performs a pattern transfer process on a color filter when preparing a color filter, for example, removing a part of the color filter by exposure development or etching to produce a truncated pyramid. Surface color filter. By the formation of the surface of the truncated pyramidal cone, the invention can greatly enhance the surface area of the color filter for absorbing light, so that more light can smoothly enter the sensitized photo by the color filter while the image sensor is developing toward a small size. The polar body, which in turn improves the problem of the surrounding vignetting. In addition, in addition to forming a truncated pyramidal surface on the color filter itself, the present invention can also form a truncated pyramidal surface on the inner lens of the protective layer and the microlens above the color filter on the protective layer according to the requirements of the product. Image sensor that also has a large light absorption surface area. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the patent scope of the present invention are intended to be within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 7 are schematic diagrams showing the method and structure of an image sensor according to a first preferred embodiment of the present invention. FIG. 8 is a schematic diagram of an image sensor according to another embodiment of the present invention. Fig. 9 is a schematic view showing the use of a color filter having a pyramid surface and a microlens to increase the incident area of light. Figure 10 is a schematic diagram of a back-illuminated CMOS image sensor of the present invention. [Main component symbol description] 96 structure 98 insulator 100 substrate 102 dielectric layer 103 interlayer dielectric layer 104 metal layer 105 intermetal dielectric layer 106 metal layer 107 planarization layer 108 protective layer 110 inner lens 112 color filter 114 Color Filter 116 Microlens 201241996 118 Microlens 122 Top Surface 124 Top Surface 126 Top Surface 128 Bevel 130 Back-illuminated CMOS Image Sensing 132 Carrier 134 矽 Substrate 136 Metal Inner Layer