CN102456540A

CN102456540A - Method for preparing photoetching overlay mark applied to epitaxial process

Info

Publication number: CN102456540A
Application number: CN2010105114072A
Authority: CN
Inventors: 王雷; 孟鸿林
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2010-10-19
Filing date: 2010-10-19
Publication date: 2012-05-16
Anticipated expiration: 2030-10-19
Also published as: CN102456540B

Abstract

The invention discloses a method for preparing a photoetching overlay mark applied to an epitaxial process, wherein the photoetching overlay mark comprises an aligned layer pattern before epitaxial growth and an aligned layer pattern after epitaxial growth, and compensation patterns with compensation growth speed difference are symmetrically added or subtracted at four corners of a photoetching mask plate of the aligned layer pattern according to the difference between the growth speed of a one-dimensional pattern and the growth speed of a two-dimensional pattern during epitaxial growth. The preparation method of the invention can reduce the epitaxial distortion caused by different growth speeds.

Description

Be applied to the preparation method of the photoetching overlay mark in the epitaxy technique

Technical field

The present invention relates to a kind of preparation method of photoetching overlay mark, particularly a kind of preparation method who is applied to the photoetching overlay mark in the epitaxy technique.

Background technology

For semiconductor high pressure high workload current device commonly used, the monocrystalline silicon that needs specific doping content and evenly doping is as Withstand voltage layer or anti-fluid layer.And that extension (also claiming EPI) technology has doping content is controlled; Doping content evenly and epitaxial loayer in strict accordance with the characteristics of crystal orientation growth, therefore in the semiconductor production of reality, all adopt grow tolerating high voltage or tolerate the rete of big electric current of the mode of epitaxial growth (EPI) usually.

But also there are some shortcomings in EPI technology when having various advantages, and pattern distortion is exactly that one of them is very important and have a strong impact on the shortcoming of follow-up photoetching Alignment Process.Because EPI is the technology of a kind of strictness based on the growth of silicon substrate crystal orientation, therefore the figure (one dimension figure, the figure that promptly extends along single direction on the plane is generally along single crystal orientation) for 1D has good anti-aliasing property (see figure 8).But for 2D figure (X-Y scheme, the i.e. figure of two the different directions extensions in upper edge, plane is generally the figure infall along two different crystal orientations); Because simultaneously along two different crystal orientation growth (see figure 9)s; This moment along with EPI technology, the variation of substrate crystal orientation and graphics shape, the growth rate that can produce the 2D position is faster or slower than the characteristic of the growth rate of 1D position; Represented like Fig. 9; The extension atom of shaded receives the influence in both direction crystal orientation, and its speed of growth and other extension atoms on every side will produce significant difference, thereby pattern distortion takes place.

Along with the speed difference of epitaxial loayer 1D growth and 2D growth becomes big, epitaxially grown thickness increases, and the pattern distortion meeting is more and more serious, causes measuring inaccurate, and the inner evenness variation is measured instability or the like, can cause under the extreme case can't measuring fully.

Summary of the invention

The technical problem that the present invention will solve provides a kind of preparation method who is applied to the photoetching overlay mark in the epitaxy technique, and it can reduce the distortion of epitaxial patterns.

For solving the problems of the technologies described above; The preparation method who is applied to the photoetching overlay mark in the epitaxy technique of the present invention; Comprise:, increased or cutting compensation figure symmetrically with compensatory growth speed difference by four jiaos of the lithography mask version of alignment figure according to the difference of the speed of growth of the speed of growth of outer time-delay one dimension figure and X-Y scheme.

Preparation method of the present invention; Characteristics according to 2D figure growth speed in the concrete epitaxy technique; Through amplify or dwindle the 2D position by the alignment figure; The final growth area of 2D position and 1D position is reached an agreement, thereby reduce because the inconsistent epitaxial patterns distortion that causes of 2D figure and 1D figure growth rate.

Description of drawings

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

Fig. 1 is of the present invention one concrete lithography mask version instance;

Fig. 2 is another concrete lithography mask version instance of the present invention;

Fig. 3 to Fig. 7 is respectively the instance of the compensation figure among the present invention

Fig. 8 is an one dimension figure epitaxial growth schematic atomic diagram;

Fig. 9 is an X-Y scheme epitaxial growth schematic atomic diagram.

Embodiment

In epitaxy technique, at 2D figure place (such as) crosspoint of the line of two different directions, the epitaxial growth meeting is carried out along a plurality of crystal orientation simultaneously, and the epitaxial growth of 1D figure is only to carry out along a crystal orientation.The growth of the growth of both direction and a direction, growth rate be along with process conditions, substrate crystal orientation, the difference of conditions such as graphics shape and difference causes the distortion of epitaxial loayer figure thus.And the preparation method who is applied to the photoetching overlay mark in the epitaxy technique of the present invention just is being based on this understanding to produce, through will or cutting a compensation figure by the increase of alignment figure before the extension, to compensate the pattern distortion that the epitaxial growth speed difference causes.Because of the preparation of photoetching overlay mark comprises being prepared by the alignment figure after the preparation of alignment figure and the epitaxial growth before the epitaxial growth; Preparation method of the present invention is specially: when being the depression figure by the alignment figure; The speed of growth of outer time-delay 1D figure is greater than the speed of growth of 2D figure; Photoetching process definition is during by the alignment figure, and employed lithography mask version is the figure after original by the alignment patterns lithography mask version four jiaos cut a compensation figure symmetrically; When the speed of growth of the outer time-delay 1D figure speed of growth less than the 2D figure, the photoetching process definition is during by the alignment figure, is the figure after increasing by a compensation figure symmetrically at original by the alignment patterns lithography mask version four jiaos.

In practical application, compensation figure can be miter angle right-angled triangle (see figure 3), square (see figure 5), 1/4 fan-shaped (seeing Fig. 6 and Fig. 7), figure and figure as shown in Figure 6 as shown in Figure 4.The size of compensation figure and concrete shape are by the speed of growth difference decision of two kinds of figures in the epitaxial growth; Can be according to the test of limited number of time, find out the relation between the epitaxial growth technology of shape, size and different-thickness of compensation figure according to the result of compensation extension distortion.The size a maximum of compensating images can be 1/4 overall dimensions, and minimum is 0.1um.Overall dimensions A by alignment photoetching alignment figure is 1～100um, is preferably 10～50um.

In an example; Be the depression figure by the alignment figure, the speed of growth of the one dimension figure extension of delaying time outward is less than the speed of growth of X-Y scheme extension, so in photoetching during by the alignment figure; Adopt lithography mask version shown in Figure 1; This lithography mask version is the figure after four jiaos of original cubic block diagram shape cut a miter angle right-angled triangle symmetrically, promptly form by the alignment figure less than original by the photoetching process definition during, and through after the epitaxial growth by the alignment figure; The final growth area of 2D figure and 1D figure is reached an agreement, reduce pattern distortion.Under an opposite situation instance; Adopt lithography mask version conduct as shown in Figure 2 by the lithography mask version of alignment figure; Be the figure after four jiaos of original cubic block diagram shape increase by a miter angle right-angled triangle symmetrically; I.e. four jiaos of miter angle right-angled triangles that stretch outward symmetrically, promptly form by the alignment figure greater than original by the photoetching process definition during, and through after the epitaxial growth by the alignment figure; The final growth area of 2D figure and 1D figure is reached an agreement, reduce pattern distortion.

In concrete design photo etched mask format, can adopt following method:

1) uses the standard lithography mask version, adopt the EPI technology growth of appointment to carry out epitaxial growth, produce three epitaxial thicknesses respectively, the thickness of standard thickness and extension control bound.One of minimum needs in batches, for more accurately also can produce more in batches.

2) the distortion judgement through test pattern needs increase still to reduce compensation figure.

3) afterwards through test, according to the result of compensation epitaxial growth distortion with model between epitaxy technique, different size and the difform compensation figure of different-thickness.

4) at last according to the size and concrete shape of the selected compensation figure of model, the figure after use is optimized is as the product figure.

Indication can be the housing in the photoetching overlay mark by alignment among the present invention, also can be the inside casing in the photoetching overlay mark.

Forming by the alignment figure with the etch silicon substrate is example, depression figure that can form through the silicon substrate of etching graph area or the protruding figure that is formed by the reservation graph area (being that the figure that the peripheral substrate zone of etching remains has afterwards formed convexity).When being during by alignment figure protruding figure; The selection of compensation figure and above-described just in time opposite; Promptly work as the speed of growth of the speed of growth of outer time-delay one dimension figure extension greater than the X-Y scheme extension; Photoetching process definition is during by the alignment figure, and employed lithography mask version is the figure after original by the alignment patterns lithography mask version four jiaos increase by a compensation figure symmetrically; When the speed of growth of the outer time-delay one dimension figure extension speed of growth less than the X-Y scheme extension, the photoetching process definition is during by the alignment figure, is the figure after cutting a compensation figure symmetrically at original by the alignment patterns lithography mask version four jiaos.Because when being the depression figure by the alignment figure, epitaxy single-crystal is outer inwardly growth; And when being protruding figure by alignment patterns, epitaxy single-crystal is from inside to outside long, so the setting of compensation figure is just in time opposite.

Claims

1. preparation method who is applied to the photoetching overlay mark in the epitaxy technique; Said photoetching overlay mark comprise before the epitaxial growth by the alignment figure after alignment figure and the epitaxial growth; It is characterized in that:, increased or cutting compensation figure symmetrically with compensatory growth speed difference by four jiaos of the lithography mask version of alignment figure according to the difference of the speed of growth of the speed of growth of outer time-delay one dimension figure and X-Y scheme.

2. according to the described preparation method of claim 1; It is characterized in that: said is when caving in figure by alignment patterns; When the speed of growth of outer time-delay one dimension figure the speed of growth greater than X-Y scheme; Photoetching process definition is during by the alignment figure, and employed lithography mask version is the figure after original by alignment figure lithography mask version four jiaos cut a compensation figure symmetrically; When the speed of growth of the outer time-delay one dimension figure extension speed of growth less than the X-Y scheme extension, the photoetching process definition is during by the alignment figure, is the figure after increasing by a compensation figure symmetrically at original by alignment figure lithography mask version four jiaos.

3. according to the described preparation method of claim 1; It is characterized in that: said when being protruding figure by alignment patterns; When the speed of growth of outer time-delay one dimension figure the speed of growth greater than X-Y scheme; Photoetching process definition is during by the alignment figure, and employed lithography mask version is the figure after original by alignment figure lithography mask version four jiaos increase by a compensation figure symmetrically; When the speed of growth of the outer time-delay one dimension figure extension speed of growth less than the X-Y scheme extension, the photoetching process definition is during by the alignment figure, is the figure after cutting a compensation figure symmetrically at original by alignment figure lithography mask version four jiaos.

4. according to each described preparation method in the claim 1 to 3, it is characterized in that: the corresponding relation between the epitaxial growth technology of the shape of said compensation figure, size and different-thickness, the result who distorts through experimental evidence compensation epitaxial growth draws.

5. according to the described preparation method of claim 4, it is characterized in that: said compensation figure is the miter angle right-angled triangle, square or 1/4 fan-shaped.

6. according to the described preparation method of claim 4, it is characterized in that: the size of said compensation figure is by the speed of growth difference decision of two kinds of figures in the epitaxial growth.

7. according to the described preparation method of each claim in the claim 1 to 3, it is characterized in that: said is the housing of photoetching overlay mark by accurate layer pattern, or is the inside casing of photoetching overlay mark.