CN216902956U

CN216902956U - Trench mos device

Info

Publication number: CN216902956U
Application number: CN202123295542.0U
Authority: CN
Inventors: 李生龙; 陈晓芸; 王蓉
Original assignee: Lanzhou Flight Control Co Ltd
Current assignee: Lanzhou Flight Control Co Ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-07-05
Anticipated expiration: 2031-12-24

Abstract

The utility model provides a trench mos device which comprises a main chip area and a peripheral protection ring area arranged outside the main chip area, wherein the main chip area protects a repeated unit cell unit, and the unit cell unit comprises a grid groove and two same contact holes which are sequentially arranged. According to the Trench mos device provided by the utility model, a single large-size contact hole in the prior art is replaced by two small-size contact holes, the small-size contact hole cannot generate obvious depression after tungsten deposition, tungsten cannot be etched on the silicon surface of the contact hole in a subsequent etching process, and a sharp wedge cannot be formed after aluminum layer sputtering, so that the product yield is improved, and the parasitic capacitance of a source electrode and a drain electrode can be reduced by the design. The production flow of the trench mos device is the same as that of the traditional trench mos device, the manufacturing cost of the product is not increased, and the electrical parameters of all aspects of the product meet the requirements at the same time.

Description

Trench mos device

Technical Field

The utility model belongs to the field of semiconductor manufacturing, and particularly relates to a trench mos device.

Background

the trench mos product, namely the trench mosfet, has high requirements on impact resistance in some application environments of the current trench mos product, and the impact resistance of the product is in direct proportion to the pitch. To meet the above requirements, a product design with a large pitch (the smallest unit cell repeat unit in the main chip area) is selected, and a large-sized trench and a large-sized contact hole are simultaneously designed as shown in fig. 2.

In actual production, for a contact hole with a large size, the surface is uneven after a tungsten deposition process is finished, a depression exists right above the contact hole, tungsten deposited by chemical vapor deposition starts to grow from two side walls of the contact hole, and a cavity or a gap is easily formed in the middle of the contact hole after a deposition procedure is finished. During the subsequent tungsten etch, the central recess portion will be etched down. The metal on the surface of the product is required to be etched cleanly, and excessive etching needs to be ensured, so that the metal on the bottom surface in the contact hole is excessively etched, and exposed silicon is formed on the surface. After aluminum layer sputtering in the subsequent process, metal aluminum can be contacted with silicon on the surface of the contact hole to form aluminum-silicon mutual melting, metal aluminum can form a sharp wedge in the silicon, the sharp wedge can be embedded into a PN junction to cause the function failure of the PN junction, and the sharp wedge can have point discharge after a device is electrified. The above-mentioned abnormalities can cause the product parameters to fail, and affect the reliability of the product. The larger the size of the contact hole is, the larger the recess generated after the deposition of the metal tungsten is, and the more obvious the phenomenon is in subsequent etching, so that the abnormality can not be avoided when the large-size contact hole is subjected to sheet flowing under the general process condition, and the problem can be frequently encountered in actual production.

Therefore, a Trench mos device that can improve the yield of products and also improve the reliability of products is desired.

Disclosure of Invention

The utility model aims to overcome the defects of the traditional Trench mos device, and meet the requirements on electrical parameters of various aspects of products while not increasing the cost of product manufacturing process.

In order to achieve the above object, the present invention provides a trench mos device, which includes a main chip region and a peripheral guard ring region disposed outside the main chip region, wherein the main chip region protects a cell unit repeatedly disposed, and the cell unit includes a gate trench and two identical contact holes disposed in sequence.

The Trench mos device provided by the utility model is also characterized in that the distance between the gate trench and the contact hole is the same as the distance between the two contact holes.

The Trench mos device provided by the utility model is also characterized in that the distance is 0.21 mu m.

The Trench mos device provided by the utility model also has the characteristic that the lower surface of the contact hole is provided with a PN junction.

The Trench mos device provided by the utility model is also characterized in that the peripheral protective ring region comprises two peripheral contact holes, and the peripheral contact holes are identical in structure with the contact holes.

Compared with the prior art, the utility model has the following beneficial effects:

according to the Trench mos device provided by the utility model, a single large-size contact hole in the prior art is replaced by two small-size contact holes, so that no obvious depression is generated after tungsten deposition of the small-size contact hole, tungsten is not etched on the silicon surface of the contact hole in the subsequent etching process, a sharp wedge is not formed after aluminum layer sputtering, parasitic capacitance is reduced, and the product quality is improved. The production flow of the Trench mos device is the same as that of the traditional Trench mos device, the manufacturing cost of the product is not increased, and the electrical parameters of all aspects of the product meet the requirements at the same time.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1: the cross-sectional view of the trench mos device provided by the embodiment of the utility model;

FIG. 2: cross-sectional view of a prior art trench mos device.

Detailed Description

In order to make the technical means, the creation features, the achievement purposes and the effects of the utility model easy to understand, the following embodiments are specifically described with reference to the attached drawings.

In the description of the embodiments of the present invention, it should be understood that the terms "central", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only used for convenience in describing and simplifying the description of the present invention, but do not indicate or imply that the device or apparatus to which the description refers must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to a number of indicated technical features. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the utility model, the meaning of "a plurality" is two or more unless otherwise specified.

The terms "mounted," "connected," and "coupled" are to be construed broadly and may, for example, be fixedly coupled, detachably coupled, or integrally coupled; can be mechanically or electrically connected; the two devices can be directly connected or indirectly connected through an intermediate medium, and the two devices can be communicated with each other. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

As shown in fig. 1, there is provided a trench mos device including a main chip region protecting a repeated unit cell unit including a gate trench 1 and two identical contact holes 2 sequentially arranged, and a peripheral guard ring region arranged outside the main chip region.

In some embodiments, the distance between the gate trench 1 and the contact hole 2 is the same as the distance between two contact holes.

In some embodiments, the distance is 0.21 μm.

In some embodiments, a PN junction 3 is disposed on the lower surface of the contact hole 2.

In some embodiments, the peripheral guard ring region includes two peripheral contact holes, and the peripheral contact holes are identical in structure to the contact holes 2.

The production process flow of the trench mos device provided by the above embodiment is as follows:

1. and depositing a mask oxide layer, and etching the groove which meets the design through the photomask.

2. Growing and removing the sacrificial oxide layer, depositing the gate oxide layer and the polysilicon, and etching the polysilicon.

3. And injecting impurities, and advancing at high temperature to form a PN junction.

4. And depositing an oxide layer, and etching the oxide layer and the epitaxial layer silicon through a photomask to form two contact holes.

5. Titanium/titanium nitride is deposited first, and then tungsten is deposited and etched.

6. And after the aluminum layer is deposited, etching according to the photomask, and leading out the corresponding polarity.

7. And depositing a protective layer, and etching according to the photomask to form surface protection.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention. The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A trench mos device, comprising a main chip region and a peripheral protection ring region disposed outside the main chip region, wherein the main chip region protects a cell unit which is repeatedly disposed, and the cell unit comprises a gate trench and two identical contact holes which are sequentially disposed.

2. The Trench mos device of claim 1, wherein a distance between the gate trench and the contact hole is the same as a distance between two contact holes.

3. The Trench mos device of claim 2, wherein the distance is 0.21 μm.

4. The Trench mos device of claim 1, wherein a PN junction is provided on a lower surface of the contact hole.

5. The Trench mos device of claim 1, wherein the peripheral guard ring region includes two peripheral contact holes, the peripheral contact holes being structurally identical to the contact holes.