A kind of deep groove type super node terminal protective structure
Technical field
The present invention relates to semiconductor integrated circuit field, particularly relate to a kind of deep groove type super node terminal protective structure. The present invention also relates to the manufacture method of a kind of deep groove type super node terminal protective structure.
Background technology
Super junction MOSFET (metal oxide semiconductor field effect transistor (MOSFET)) has super-junction structures because of it, namely there is alternately arranged P type and N-type silicon epitaxy post layer on a semiconductor substrate, make the PN knot of this device p type island region and N-type region in the off state produce depletion layer, thus improve the withstand voltage of device.
In the design process of super junction-semiconductor device, except needs cellular region have sufficiently high withstand voltage except, the withstand voltage height of super junction is also played a key effect by the design of its terminal domain structure. Common terminal domain structure is designed to the groove of multiple floating, and groove inserts p-type polysilicon, is exhausted by these p-type polysilicon and N-type epitaxy layer and reduces transverse electric field, and protection cell region is not punctured by transverse electric field.
Deep groove super knot product utilizes etching deep trench then to insert the silicon that mixes with substrate phase transoid with fill process (such as EPI technique) in deep trench to realize. For product terminal protection ring often can use spacing distance not wait groove ring to form terminal protection structure. It is the narrowest ring of width for the groove ring of outmost turns in the design. And in actual product is processed; narrow ring filling (such as EPI fill process) is the most difficult; particularly in the place of chamfering (corner); there will be straight flange position to fill completely and occur that in chamfering (corner) position the problem filled is (as shown in Figure 1; cavity such as occurs); chamfering (corner) is not if the filling of the deep trouth at place is very fully (as there is cavity); the terminal protection of super junction product can be caused inadequate, reduce voltage breakdown and the reliability of product.
Summary of the invention
The technical problem to be solved in the present invention be to provide a kind of deep groove type super node terminal protective structure when can not affect exhaust between groove; groove ring can be made to fill more abundant; the situation that groove ring chamfering (corner) position generating portion is filled can be avoided, it is to increase the Performance And Reliability of product.
The super junction terminal protection structure of the present invention, it is included on substrate and it is etched with many width differences, it is spaced apart from different groove rings, the identical deep trench of many width it is etched with in chip internal groove ring, the width of outermost groove ring is a, chip internal deep trench width is b, a < b; Wherein, described outermost groove ring becomes wide outside chamfering place, and described outermost groove ring chamfering place groove width is greater than other position groove width of this groove.
Described outermost groove ring chamfering place width is increased to gradually by a after being more than or equal to b and returns to a gradually.
The super junction terminal protection structure of the present invention; by increasing width outside the groove ring of outermost; exhausting between groove can not be affected; puncturing of product can not be impacted; groove ring can be made to fill more abundant; the situation that deep trouth ring chamfering (corner) position generating portion is filled can be avoided, it is to increase the Performance And Reliability of product.
Accompanying drawing explanation
Below in conjunction with accompanying drawing and embodiment, the present invention is further detailed explanation:
Fig. 1 is the schematic diagram of a kind of existing super junction terminal protection structure.
Fig. 2 is super junction terminal protection structure first embodiment schematic diagram of the present invention.
Fig. 3 is super junction terminal protection structure the 2nd embodiment schematic diagram of the present invention.
Description of reference numerals
1 is outermost groove ring
A is outermost groove ring non-chamfering (corner) position width
B is deep trench width
Embodiment
As shown in Figure 2, in super junction terminal protection structure first embodiment of the present invention, substrate is etched with many width differences, it is spaced apart from different groove rings, the identical deep trench of many width it is etched with in chip internal groove ring, the width of outermost groove ring is a, and chip internal deep trench width is b, a < b; Wherein, described outermost groove ring becomes wide outside chamfering (corner) place, and described outermost groove ring chamfering (corner) place groove width is b.
As shown in Figure 3, in super junction terminal protection structure the 2nd embodiment of the present invention, substrate is etched with many width differences, it is spaced apart from different groove rings, the identical deep trench of many width it is etched with in chip internal groove ring, the width of outermost groove ring is a, and chip internal deep trench width is b, a < b; Wherein, described outermost groove ring becomes wide outside chamfering (corner) place, and described outermost groove ring chamfering (corner) place groove width returns to a after being increased to b gradually by a gradually.
Below through the specific embodiment and the embodiment to invention has been detailed description, but these are not construed as limiting the invention. Without departing from the principles of the present invention, the technician of this area also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.