Vertical anti-blooming CCD manufacturing technology

Abstract

The invention provides a vertical anti-blooming CCD manufacturing technology which comprises the steps that 1) an N-type mono-crystalline silicon wafer is provided; 2) an oxide layer is formed on the surface of the N-type mono-crystalline silicon wafer; 3) phosphorous ion injection is performed on the N-type mono-crystalline silicon wafer so that a certain thickness of phosphorous ion injection region is formed in the N-type mono-crystalline silicon wafer; 4) activation processing is performed on the phosphorous ion injection region, and an N-type sandwich layer is formed in the activated phosphorous ion injection region; 5) the oxide layer on the surface of the N-type mono-crystalline silicon wafer is removed; 5) an epitaxial layer is grown on the N-type mono-crystalline silicon wafer so that a substrate is formed; and 7) a gate medium, a p-well, channel resistance, channels, a transfer gate, connecting holes and a metal lead wire are manufactured on the substrate in turn. The beneficial technical effects of the vertical anti-blooming CCD manufacturing technology are that resistivity heterogeneity of the N-type sandwich layer is reduced, and homogeneity control of a large-scale vertical anti-blooming CCD is facilitated. Only the primary epitaxial technology is adopted by the vertical anti-blooming CCD manufacturing technology so that integral controllability of the technology is relatively high.

Description

technical field [0001] The invention relates to a CCD manufacturing process, in particular to a longitudinal anti-halation CCD manufacturing process. Background technique [0002] When the CCD image sensor is in a strong light environment, due to the generated photo-generated electrons exceeding the well capacity, the excess electrons will diffuse toward the adjacent pixels. This situation is called the halo phenomenon; An anti-halation structure is set in the image sensor, which can draw away excess electrons, thereby suppressing the halo phenomenon; common anti-halation structures include horizontal anti-halation structures and vertical anti-halation structures, among which the vertical anti-halation structure is due to It will not occupy the area of ​​the photosensitive area and reduce the duty cycle of the device, which has greater advantages. [0003] The traditional vertical anti-corona structure is to grow the gate dielectric on the substrate and carry out P-well fab...

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Problems solved by technology

[0003] The traditional vertical anti-corona structure is to grow the gate dielectric on the substrate and carry out P-well fabrication to form a vertical anti-corona barrier. By adjusting the P-well concentration, different anti-corona barrier heights can be obtained. In practical applications, The longitudinal anti-corona voltage of this vertical anti-corona structure is relatively large, resulting in high power consumption of the device; in order to reduce the anti-corona voltage, foreign manufacturers have optimized the silicon substrate from the original N-type substrate to N-type sandwich Layered epitaxial silicon substrate, its structure is: epitaxial layer / N-type sandwich layer / substrate layer; this kind of epitaxial silicon substrate with N-type sandwich layer, the epitaxial layer and N-type sandwich layer on it are made by epitaxial process , due to the difficulty in controlling the epitaxial process, the non-uniformity of the resistivity of the obtained N-type sandwich layer is ≤16%, and affected by the non-uniformity of the resistivity of the N-type sandwich layer, the non-uniformity of the resistivity of the epitaxial layer is ≤15%, In this case, it is not conducive to the uniformity control of large-scale (4096 yuan × 4096 yuan and above) longitudinal anti-halation CCD

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