A deep trench filling method

A filling method and deep trench technology, which is applied in the direction of electrical components, circuits, semiconductor devices, etc., can solve the problems of inconsistent PN volume ratio and reduce the withstand voltage capacity of the depletion region, so as to reduce the difference of impurity amount and reduce the filling time , The effect of reducing product cost

CN106229335AInactive Publication Date: 2016-12-14SHANGHAI HUAHONG GRACE SEMICON MFG CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2016-12-14
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a deep trench filling method, in which deep grooves are filled with epitaxial layers until the epitaxial layers on the side walls of the trenches gather up at the bottom portions, and non-conductive mediums are used to fill the residual gaps in the trenches until the trenches are full. According to the deep trench filling method of the invention, the epitaxial filling is stopped after the bottom portions of the epitaxial layers gather up and before the top portions of the expixial layers gather up, and the epitaxial volumes of the bottom portions and the top portions of the epitaxial layers are kept to be approximate to each other. Since the impurity levels in the filling epitaxial layers are proportional to the volumes, the filling method can reduce the difference in the amount of impurities in the bottom and upper portions of the deep trenches and improve the uniformity of depletion regions so that the differences in the depletion degrees of the trenches at different depths are slight, thereby raising the overpressure resistant efficiency of the depletion regions and improving the overpressure resistant capability of products.
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Description

technical field

[0001] The invention relates to the field of semiconductor manufacturing, in particular to a deep trench filling method. Background technique

[0002] For existing deep trench super junction products, the deep trench etching and epitaxial filling method is used to process the PN structure of the super junction products. However, the epitaxial filling rate of deep trench products is slow, and it takes a long time for epitaxial growth to completely fill the trenches, occupying the production capacity of epitaxial equipment, which is not conducive to mass production.

[0003] The sidewall of the deep groove processing will have a certain angle, such as figure 1 As shown, the cross section of the groove is an inverted trapezoid, and the width of the edge of the groove is greater than the width of the bottom of the groove. The filling is done as figure 2 As shown, after epitaxial filling, the PN volume ratio at the top and bottom is inconsistent, that is, the ...

Examples

Embodiment Construction

[0016] Deep trench filling method of the present invention, such as image 3 As shown, there is a deep trench in the substrate 1. In the deep trench, it is first filled with P-type or N-type epitaxy 2, and the epitaxy 2 is filled to the extent that the epitaxy of the sidewall of the trench is closed after the bottom is closed and before the top is closed. Then use a non-conductive medium such as silicon dioxide or non-doped polysilicon to continue filling the remaining space in the trench until the trench is fully filled.

[0017] The general filling time is 30% to 80% of the full filling time.

[0018] During epitaxial filling, since the epitaxial growth is constant growth along the sidewall of the deep trench, the epitaxial growth is stopped during the period from the bottom of the epitaxial to the top of the close, and the concentration of the epitaxial is calculated by the actual filled epitaxial thickness. refer to:

[0019] N epitaxial concentration × N epitaxial width...