CN101752203B

CN101752203B - Preparation method of inclined groove

Info

Publication number: CN101752203B
Application number: CN2008100441206A
Authority: CN
Inventors: 肖胜安
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2008-12-17
Filing date: 2008-12-17
Publication date: 2012-06-20
Anticipated expiration: 2028-12-17
Also published as: CN101752203A

Abstract

The utility model discloses a preparation method of an inclined groove which mainly comprises the following steps: engraving on a silicon substrate by utilizing a mask layer to form the groove, carrying out inclined ion injection and thermal oxidation, removing a thermal oxidation film and the like. The preparation method of the inclined groove can obtain 80-90-degree scope of an inclination angle of the inclined groove through adjusting an ion injection process and a thermal oxidation process.

Description

The preparation method of inclined groove

Technical field

The present invention relates to a kind of preparation method of groove, particularly a kind of preparation method of inclined groove.

Background technology

Groove structure is widely used for realizing isolating, the making capacity, or make MOSFET etc.In the existing groove manufacturing technology; No matter utilize photoresist to do mask protection or utilize deielectric-coating to do mask protection; All be to realize that through the technology of adjusting etching groove the groove that needs tilts; But this method is bigger in the degree of depth of groove, or the depth-width ratio of groove just is difficult to reach requirement when higher.Utilize deielectric-coating to do under the situation of trench etching mask; Because being difficult to generate enough polymer protects trenched side-wall; All difficultly under the shallow trench situation obtain big inclination angle, when dark or depth-width ratio was big at the groove that requires, the inclination angle that obtain to expect was impossible basically.In the technology of doing mask with photoresist; The polymer that photoresist produces can provide the protection that needs to obtain inclined groove for trenched side-wall; But when dark or depth-width ratio was big when the groove that requires, for the inclination angle that needing to obtain, the polymer of oppose side wall protection had certain requirement; At this moment the bottom of groove will be too many because of polymer in the etching process, is difficult to carry out uniform etching.

Summary of the invention

The technical problem that the present invention will solve provides a kind of preparation method of inclined groove, and it can prepare the bigger groove of depth-width ratio of inclination.

For solving the problems of the technologies described above, the preparation method of inclined groove of the present invention has at least after etching forms groove on the silicon substrate of a mask layer on the surface, comprises the steps:

1) angle-tilt ion that said groove is rotated is injected, and the condition that said ion injects is set according to the angle of inclination of the groove that said needs obtain;

2) then carry out oxidation processes, make the silica of trenched side-wall turn to silica;

3) mask layer on the said silicon substrate of removal and the silica of said trenched side-wall obtain the groove of trenched side-wall than the trenched side-wall inclination of institute's etching in the step 2.

The mode of the present invention through utilizing angle-tilt ion to inject; Make the trenched side-wall at differing heights place accept different ion concentrations; Through thermal oxidation technology trenched side-wall is carried out oxidation then; Because of the silicon area of ion after injecting be easy to oxidized, so the heat oxide film thickness of trenched side-wall is reduced along with the increase of gash depth (apart from the distance at top) or says that the oxidized amount that makes sidewall upper substrate material silicon reduces with the degree of depth increase of groove, removes the heat oxide film of generation at last; The groove structure that obtains tilting, make groove structure can satisfy the integrated requirement of subsequent technique (for example make follow-up groove fill out membrane process be easy to obtain not have the cavity film etc.).Through adjustment ion implantation technology and thermal oxidation technology among the preparation method of inclined groove of the present invention, can obtain the groove tilt angle ranges is 80-90 degree (angle between trenched side-wall and the vertical line).

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed explanation:

Fig. 1 is the structural representation behind the etching groove among the preparation method of embodiment of the present invention;

Fig. 2 is the structural representation that preparation method's intermediate ion of embodiment of the present invention injects;

Fig. 3 is the structural representation after the thermal oxidation among the preparation method of embodiment of the present invention;

Fig. 4 is the structural representation of removing among the preparation method of embodiment of the present invention behind the silica.

Embodiment

The preparation method of inclined groove of the present invention has at least after etching forms groove on the silicon substrate of a mask layer on the surface, comprises the steps:

1) angle-tilt ion that groove is rotated is injected, and the condition that ion injects is set (ion implanting conditions of indication mainly refers to angle of inclination, ion implantation concentration and energy etc.) here according to the angle of inclination of the groove that said needs obtain;

Above-mentioned mask layer can be photoresist layer, and to add dielectric layer (as shown in Figure 1; Define by photoresist that etching dielectric layer and silicon substrate form groove behind the groove position); Also can be directly be dielectric layer (after defining the groove position by photoetching process; The etching dielectric layer forms hard mask layer, and photoresist is removed in the back, forms silicon substrate with the dielectric layer for the mask etching silicon substrate).The groove that is etched can be 90 degree, also can be the groove with certain gradient.

The (see figure 2) when angle-tilt ion that groove is rotated is injected; The condition that ion injects is set according to the angle of inclination of the groove that said needs obtain; Generally that the angle of inclination of required groove is big more; Also the phase strain is big at angle of inclination when ion injects, and the ion of injection can be any of phosphorus, arsenic, boron, germanium or silicon, also can be the material that comprises above-mentioned any ion; This step ion injects and makes the different depth of trenched side-wall that different ions concentration arranged; The ion concentration of trenched side-wall reduces with the increase of gash depth; In ion implantation process; Can comprise big inclination and inject, little inclination angle is injected or their combination, also can be through injection that repeatedly condition is different to achieve the goal.As adopt dielectric layer shown in Figure 1 to add the scheme of photoresist;, ion needs to remove photoresist after injecting; The removal of photoresist can adopt dry method to remove photoresist to add the wet method technology of removing photoresist, the polymer that also can only remove photoresist and possibly generated by etching technics in the step 2 with wet method.As having only dielectric layer on the silicon substrate, then the removal of dielectric layer is consistent with the removal step of silica in the step 3.

And in oxidation processes; Because of the silicon after the ion injection more is prone to oxidized (oxidized amount is directly proportional with the volume density of injection region ion); So the pattern of resulting silica is consistent in the distribution of silicon substrate with ion, promptly the silicon oxide thickness of trenched side-wall reduces (see figure 3) along with the increase of gash depth (apart from the distance at top), more tilts for making final groove; Also can before oxidation processes, carry out The high temperature anneal; With the distribution of adjustment ion on trenched side-wall, make it along the trenched side-wall horizontal proliferation, the thickness of the silica that should locate in the oxidation processes after making increases;

Remove the silica (also will remove dielectric layer if desired) of said trenched side-wall afterwards; And the silica that in oxidizing process, possibly on the silicon plane, grow; Because of silica is more and more thinner distribution at the thickness of trenched side-wall from top to bottom, so finally obtain the groove (see figure 4) of trenched side-wall than the trenched side-wall inclination of institute's etching in the step 2.

Claims

1. the preparation method of an inclined groove, the A/F of said inclined groove is characterized in that greater than the bottom width of groove, has at least after etching forms groove on the silicon substrate of a mask layer on the surface, comprises the steps:

1) angle-tilt ion that said groove is rotated is injected; The angle of inclination of the said groove that the condition that said ion injects obtains is as required set, the ion that is injected be phosphorus, arsenic, boron, germanium or silicon any or for comprising the material of above-mentioned any ion;

3) remove mask layer and the silica of said trenched side-wall on the said silicon substrate, obtain trenched side-wall than step 2) in the groove that tilts of trenched side-wall.

2. according to the described preparation method of claim 1, it is characterized in that: comprise also before that said step 2) silicon chip to carrying out after ion injects carries out the step that high-temperature process distributes the ion of said injection again.

3. according to claim 1 or 2 described preparation methods, it is characterized in that: said mask layer is dielectric layer or photoresist layer; When said mask layer was photoresist layer, the mask layer of removing in the said step 3) on the silicon substrate was adjusted into step 2 after step 1)) carry out before.

4. according to claim 1 or 2 described preparation methods, be characterised in that: be injected to repeatedly the different injection of ion implanting conditions in the said step 1).