1. Field of the Invention
The present invention relates to a method of fabricating a color image sensor device, and in particular to a method of fabricating a color image sensor device with protected contact pads and uniform color filter layers.
2. Brief Discussion of the Related Art
Color image sensor chips usually comprise a sensor pixel array disposed in a central region and a plurality of contact pads in a peripheral region. In conventional fabrication, the sensor pixel array and the contact pads are preformed in fabs by front-end process with a color filter layer then fabricated thereon.
In U.S. Pat. No. 6,344,369, Huang et al. provide a method of fabricating a color image sensor device capable of preventing contact pads from developer solution damage, in which
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The method disclosed in U.S. Pat. No. 6,344,369 prevents the contact pads 13 from oxidation or corrosion during color image sensor device fabrication. During the disclosed fabrication, however, the first planarization layer 30 is photolithographically exposed, developed and baked several times. Thus, the first opening 60a cannot be formed in the first and second planarization layers 30, 50 by a sequential development step, making the fabrication step in
Accordingly, an embodiment of the invention provides a method for forming a color image sensor device, comprising providing a substrate having a sensor pixel array and a contact pad. A passivation layer is formed on the substrate, covering the sensor pixel array and the contact pad. A first planarization layer is formed on the passivation layer. A plurality of color filter elements are formed on the first planarization layer in positions corresponding to the sensor pixel array. A second planarization layer is formed on the first planarization layer, covering the color filter elements. A first opening is formed in the second planarization layer, exposing the first planarization layer, wherein the first opening is formed in a position corresponding to the contact pad. Dry etching performed on the first planarization layer along the first opening forms a second opening in the first planarization layer and the passivation layer and exposes the contact pad.
A color image sensor device is also provided, comprising a substrate having a sensor pixel array and a contact pad thereon and a passivation layer disposed over the substrate, covering the sensor pixel array and the contact pad. A first planarization layer covers the passivation layer and a plurality of color filter elements over the first planarization layer corresponding to the sensor pixel array. A second planarization layer over the first planarization covers the color filter elements and a third planarization layer over the second planarization comprises an opening corresponding to the contact pad. A second opening is formed in the second planarization layer corresponds to the contact pad, also does a third opening in the first planarization layer and the passivation layer.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the subsequent detailed description and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
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Next, a third planarization layer 170 is formed on the second planarization 150 and fills the first opening 160a. The third planarization may comprise photoresist with light transmittance not less than 95%, such as photosensitive polyimide or other negative-type photoresists. The third planarization layer 170 may comprise the same material as that of the first and second planarization layers 130, 150. Next, sequentially exposing and developing are performed, thus forming a second opening 160b therein, exposing the top surface of the first planarization layer 130 in the second opening 160b.
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As illustrated in rig. 3F, a color image sensor device is also provided, comprising a substrate with a sensor pixel array in a central region and a contact pad in a peripheral region. A passivation layer 120 on the substrate 100 covers the sensor pixel array and the contact pad. A first planarization layer 130 is on the passivation layer 120. Color filter layers 140R, 140G, 140B on the first planarization layer 130 correspond to the sensor pixel region. A second planarization layer 150 on the first planarization layer 130 covers the color filter layers 140R, 140G, 140B. An opening (i.e. the first opening 160a) in the second planarization layer 150 corresponds to the contact pad 113 as does the third opening 160c in the first planarization layer 130 and the passivation layer 120. The color image sensor device further comprises a third planarization layer 130 formed on the second planarization layer 150, having yet another opening (referring to the second opening 160b) corresponding to the contact pad 113, and microlens elements 180 disposed on the third planarization layer 170 correspond to the sensor pixel array.
One of the potential advantages of the described embodiment is a contact opening down to the contact pad is formed after formation of the color filter layers and corrosion thereto by a developer solution used for developing the color filter layers can be thus prevented. In addition, the contact opening is formed in the first planarization layer 130 and the passivation layer 120 by a dry etching and exposes top surface of the contact pad 113. The first planarization layer 130 is exposed and developed for several times during formation of the color filter layers and the contact opening can be formed only by dry etching but cannot formed by developer development.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Number | Date | Country | Kind |
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93116405 | Jun 2004 | TW | national |
This application is a Divisional of co-pending application Ser. No. 11/000,935, filed on Dec. 2, 2004, and for which priority is claimed under 35 U.S.C. §120; and this application claims priority of Application No. 093116405, filed in Taiwan, R.O.C. on Jun. 8, 2004 under 35 U.S.C. §119; the entire contents of all are hereby incorporated by reference.
Number | Date | Country | |
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Parent | 11000935 | Dec 2004 | US |
Child | 11934002 | Nov 2007 | US |