Silicon chip mark and its implementation and read method
Technical field
The present invention relates to the mark of silicon chip in a kind of semiconductor manufacturing.
Background technology
In semiconductor is made, for silicon chip is followed the trail of, put into production beginning of line at silicon chip, just need be in the enterprising row labels of silicon chip.Silicon chip mark commonly used now sees also Fig. 1, and mark 11 is character and/or digital combination normally.This silicon chip mark is to engrave mark 11 to realize on the surface of silicon chip 10.
The defective of this silicon chip mark has two: one, need manually read this mark and realize tracking to silicon chip, loaded down with trivial details, the inefficiency of working and be easy to generate error; The 2nd, automatic identification can't be realized, thereby automatic tracking can't be realized silicon chip to this mark.
Summary of the invention
Technical problem to be solved by this invention provides a kind of silicon chip mark, and this silicon chip mark can be realized the automatic identification to silicon chip, thereby realizes the automatic tracking to silicon chip.For this reason, the present invention also provides the implementation method and the read method of described silicon chip mark.
For solving the problems of the technologies described above, silicon chip mark of the present invention is used to distinguish different silicon chips, and described silicon chip mark is the one or more gratings that form at silicon chip surface, and described a plurality of gratings have different space periodics, represent different label symbols respectively.
Described label symbol comprises Chinese character, outer Chinese character or numeral.
Described grating is a reflecting grating.
The implementation method of silicon chip mark of the present invention is to adopt delineation equipment to delineate a plurality of grooves at silicon chip surface, and the groove of delineating constitutes one or more gratings, and described a plurality of gratings have different space periodics.
The implementation method of silicon chip mark of the present invention is to adopt photoetching and/or etching technics to form a plurality of grooves at silicon chip surface, and the groove that forms constitutes one or more gratings, and described a plurality of gratings have different space periodics.
Described etching technics comprises dry etching and wet etching.
The read method of silicon chip mark of the present invention is to use the described one or more gratings with different spaces cycle of laser radiation, discern each grating diffration diffraction of light angle then, according to the different angles of diffraction each grating is identified as different label symbols again.
Silicon chip mark of the present invention and its implementation and read method can be realized automatic identification and the tracking to silicon chip, enhance productivity, and stop the error that manual operation may cause.
Description of drawings
The present invention is further detailed explanation below in conjunction with drawings and Examples:
Fig. 1 is the schematic diagram of existing silicon chip mark;
Fig. 2 is the schematic diagram of silicon chip mark of the present invention;
Fig. 3 is the schematic diagram of reflecting grating;
Reference numeral is among the figure: the 10-silicon chip; 11-tradition silicon chip mark; 21-silicon chip mark of the present invention; The 211-grating; The 212-grating; The 30-reflecting grating; 31-grating planar normal; The 32-incident light; The 33-diffraction light; The d-space periodic; θ
0-incidence angle; θ-angle of diffraction.
Embodiment
See also Fig. 2, silicon chip mark of the present invention is the mark 21 that forms on the surface of silicon chip 10, and mark 21 is one or more gratings, and Fig. 2 schematically provides two gratings 211 and 212.The present invention requires to have different space periodics as a plurality of gratings of silicon chip mark 21, and these a plurality of gratings with different spaces cycle are represented different label symbols respectively.So-called label symbol can be a kind of symbols encoded, and more common then is Chinese character, outer Chinese character or numeral.For example, use 26 gratings just can represent 26 English alphabets, re-use 10 gratings and can also represent 10 Arabic numerals again with different spaces cycle with different spaces cycle.
The implementation method of silicon chip mark of the present invention is to form one or more gratings at silicon chip surface.Form grating at silicon chip surface and can adopt delineation equipment to realize, also can adopt photoetching and/or etching technics in the semiconductor manufacturing to realize at silicon chip surface delineation groove.These have many document introductions in the method that silicon chip surface forms grating, do not repeat them here.Adopt the formed a plurality of gratings of which kind of implementation method all to have different space periodics.
Grating comprises transmission grating and two kinds of forms of reflecting grating,, realizes for the ease of technology also that the present invention serves as preferred to adopt reflecting grating in order silicon chip not to be caused damage.See also Fig. 3, this is the schematic diagram of reflecting grating.Wherein the space periodic of reflecting grating 30 (being also referred to as grating constant) is d, and incidence angle is θ
0Incident light 32 shine on the reflecting grating 30, the angle of diffraction of diffraction light 33 is θ.In Fig. 3 (a), incident light 32 and the heteropleural of diffraction light 33 at grating planar normal 31, incident light 32 satisfies following equation: d (sin θ-sin θ with diffraction light 33 so
0)=j λ.In Fig. 3 (b), incident light 32 and the homonymy of diffraction light 33 at grating planar normal 31, incident light 32 satisfies following equation: d (sin θ+sin θ with diffraction light 33 so
0)=j λ.J wherein gets 0, and ± 1, ± 2 ..., λ is the wavelength of incident light 32.When incident light 32 along 31 incidents of grating planar normal, i.e. θ
0Be 0, diffraction light satisfies following equation so: dsin θ=j λ.
The read method of silicon chip mark of the present invention is to use the described one or more gratings with different spaces cycle of laser radiation, discern each grating diffration diffraction of light angle then, according to the different angles of diffraction each grating is identified as different label symbols again.Under the certain situation of incident light (laser), its incidence angle θ
0Also certain with wavelength X, each grating diffration diffraction of light angle θ is just only relevant with the space periodic d of this grating.So just, realized using the grating in different spaces cycle to represent different label symbols, the difference of the angle of diffraction by diffraction light is identified as the grating in different spaces cycle again, finally is identified as the purpose of different label symbol.
Use silicon chip mark of the present invention and realization and read method, can put into production beginning of line, just on silicon chip, form one or more gratings and serve as a mark with different spaces cycle at silicon chip.In any step thereafter, can utilize laser that this silicon chip mark is scanned, and according to the difference identification silicon chip of the angle of diffraction of diffraction light, thereby realize automatic identification silicon chip.Also but integrated laser reads the equipment of mark in existing each production equipment, can also realize like this in the production process to silicon chip from motion tracking, not only realized automation control silicon chip, also improved operating efficiency, avoided the people for reading issuable error.