CN1109260C

CN1109260C - Making process of great-angle Y-branch silicon luminous-power distributor

Info

Publication number: CN1109260C
Application number: CN 00115582
Authority: CN
Inventors: 王跃林; 王文辉; 李铁; 解健芳
Original assignee: Shanghai Institute of Metallurgy of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2000-04-29
Filing date: 2000-04-29
Publication date: 2003-05-21
Anticipated expiration: 2020-04-29
Also published as: CN1274857A

Abstract

The present invention relates to a making process of a Y-branch silicon light power distributor with a large angle, which is mainly characterized in that the refractivity of branching positions is changed by a doping method; the Y-branch silicon light power distributor with a large angle is arranged on a glass substrate by a technology that the linkage and the dual-surface photoetching are carried out after doping. The present invention has the advantages that the back surface is doped, and the facade is etched, so that the doping depth is properly reduced to satisfy the requirements of a ridge-shaped waveguide having a large cross section. In addition, the limiting effects of the glass substrate to light are good.

Description

A kind of method for making of great-angle Y-branch silicon luminous-power distributor

The present invention relates to luminous-power distributor, particularly a kind of method for making of great-angle Y-branch silicon luminous-power distributor.

Luminous-power distributor is the important component part in passive photonic loop, optical fiber cable TV (CATV) and the EPON (PON).Making luminous-power distributor has several different methods, is broadly divided into three kinds of discrete optical elements sets mould assemblys, full fiber type, planar waveguide-type.Wherein, the planar waveguide-type luminous-power distributor is the luminous-power distributor that utilizes planar medium optical waveguide technology to make, have volume little, in light weight, be easy to integrated, machinery and environmental stability is good, splitting ratio is easy to accurately control and produce the extremely low advantage of cost in batches, be optical fiber communication development in future trend.The planar waveguide-type luminous-power distributor has multiple structure, as multi-mode interference-type (MMI), and bimodulus interfere type (TMI), X branching type, Y branching type etc.Wherein the Y branched structure is the simplest, and the theoretical analysis fullest is most widely used.

The angle that common Y branch optical power distributer separates in bifurcation is generally the 1-2 degree, if branches angle increases, the loss of bifurcation will increase sharply.Because the distance that waveguide finally separates is certain, the smaller branching angle makes device have bigger length, and meanwhile, the subbranch angle proposes higher requirement also for the preparation of mask and technology.By changing the refractive index (shown in accompanying drawing 1,2) in the certain zone of bifurcation, branches angle can be increased to the 10-20 degree.For silica-based optical waveguide material, the refractive index that can reduce silicon by the method for mixing realizes the preparation of great-angle Y-branch luminous-power distributor.The proposition of heavy in section ridge waveguide theory has solved the problem of silica-based waveguides end face and the serious mismatch of single-mode fiber core diameter, for road has been paved in the application of silica-based optical waveguide, but simultaneously owing to the increase of waveguide dimensions, has higher requirement to technologies such as doping.Doping depth will reach the 5-8 micron, i.e. the height of ridge waveguide (as shown in Figure 3), and doping content can not be very low, and technology realizes very difficulty.

The object of the invention provides a kind of method for making of great-angle Y-branch silicon luminous-power distributor.

The method for making of great-angle Y-branch silicon luminous-power distributor of the present invention is, adopt silicon to make ducting layer, glass is made limiting layer, the making of silicon waveguide is the one side doping another side lithographic technique that adopts silicon chip, and after mixing on the silicon chip silicon chip mixed earlier face and glass are good for and are closed and utilize double face photoetching machine that ducting layer is carried out the technology of dual surface lithography and make.It comprises the following steps: that (1) makes the graphical window of doped region on silicon chip, and at first thermal oxide layer of silicon dioxide on the silicon chip of twin polishing makes the doping window then by lithography, uses the hydrofluorite corrode silicon dioxide, obtains the window that mixes; (2) expand boron, give deposit earlier, distribute again, remove Pyrex with hydrofluorite; (3) silicon chip doping face and glass bonding, the expansion boron doping face bonding of the polished surface of glass and silicon chip, its condition is: bonding temperature 300-400 ℃, bonding voltage 800-1600 volt; (4) wafer thinning is used chemical corrosion, or galvanic corrosion, or the method for mechanical buffing or its combination with wafer thinning to required thickness; (5) make the aluminium mask, evaporation of aluminum on silicon face, aluminum layer thickness is the 2000-4000 dust; (6) dual surface lithography is made the waveguide figure, utilizes double face photoetching machine that ducting layer is carried out dual surface lithography, goes out waveguide graphical window with phosphoric acid corrosion after the photoetching; (7) corrode or etch ridge waveguide; (8) remove aluminium, scribing can make after the end face polishing.The technology of described wafer thinning is: behind (1) bonding, 60 ℃ of corrosion, also remain about 40 micron up to silicon chip with 50% potassium hydroxide solution; (2) with mechanical polishing method with wafer thinning to desired thickness.

The advantage of the great-angle Y-branch silicon luminous-power distributor that the present invention makes is as follows:

1, the one side another side lithographic technique that mixes has reduced the doping depth of great-angle Y-branch luminous-power distributor optical waveguide.Because the ridged outshot of ridge waveguide is strong restricted type waveguide, mix the situation of positive etching ridge waveguide in the front under, it is little to the propagation effect of light to mix, under at present limited doping depth limited, doped portion can not effectively utilize.When adopting the back side to mix positive etching, back side doped portion can be kept fully, so doping depth suitably reduces just can satisfy the requirement of heavy in section ridge waveguide.

2, adopt glass substrate good to the restriction effect of light.Because limiting layer is thick more, waveguide is more little in the loss of limiting layer.The limiting layer of silicon waveguide promptly is a glass substrate in the method for making of the present invention, and limiting layer thickness is substrate thickness, and its thickness is generally the hundreds of micron, therefore, has better restriction.

The invention will be further described below in conjunction with embodiment and accompanying drawing.

Fig. 1, one of great-angle Y-branch luminous-power distributor synoptic diagram.

Fig. 2, two of great-angle Y-branch luminous-power distributor synoptic diagram.

Fig. 3, the comparison of mixing in the positive doping and the back side.

Fig. 4, great-angle Y-branch silicon luminous-power distributor manufacture craft embodiment process flow diagram of the present invention.

Fig. 1 is one of great-angle Y-branch luminous-power distributor synoptic diagram, and figure intermediate cam shape zone is refractive index and reduces the zone.Fig. 2 is two of great-angle Y-branch luminous-power distributor synoptic diagram, and is opposite with Fig. 1, is refractive index in the figure intermediate cam shape and increases the zone.Fig. 3 is the comparison diagram that mixes in the positive doping and the back side, a1, a2 is positive the doping, and b1, b2 are to mix in the back side, the dark colour zone is a doped region, by the figure contrast as seen, reach same doping effect, the doping depth of back side doping process is much smaller, so doping depth suitably reduces, still can satisfy the requirement of heavy in section ridge waveguide.

Fig. 4 is the technological process that the present invention makes an embodiment of great-angle Y-branch silicon luminous-power distributor, the characteristics of this technological process are: adopt silicon to make ducting layer, glass is made limiting layer, doping front, back side lithographic technique, after mixing on the silicon chip silicon chip being mixed earlier, face and glass are strong to be closed and utilizes double face photoetching machine that ducting layer is carried out the technology of dual surface lithography, and specifically making step is as follows:

A. silicon chip twin polishing;

B. the silicon dioxide of silicon chip thermal oxide one deck 1 micron thickness, 1150 ℃ of oxidizing temperatures, oxidization time is 3 hours.Logical dried oxygen is 15 minutes during oxidation, 2 hours 30 minutes wet oxygens, 15 minutes dried oxygen;

C. make the doping window by lithography, use the hydrofluorite corrode silicon dioxide, obtain the window that mixes;

D. expand boron, at first gave deposit 60 minutes, giving deposition temperature is 1050 ℃, and then distributes 6 hours, and districution temperature is 1180 ℃ again;

E. remove Pyrex with hydrofluorite immediately after distributing again;

F. mix face and glass bonding, the diffusingsurface bonding of the polished surface of glass and silicon chip, bonding temperature are 380 ℃, bonding voltage is 1400 volts.Judge by Direct observation whether bonding is finished;

G. wafer thinning, behind the bonding with 50% potassium hydroxide solution 60 ℃ of corrosion, when the also surplus 40 microns left and right sides of silicon chip, stop corrosion, with mechanical polishing method with wafer thinning to desired thickness;

H. make the aluminium mask, evaporation of aluminum on silicon face, aluminum layer thickness is 3000 dusts;

I. dual surface lithography is made the waveguide figure, utilizes double face photoetching machine to carry out dual surface lithography, goes out waveguide graphical window with phosphoric acid corrosion after the photoetching;

J. reactive ion etching goes out ridge waveguide;

K. remove aluminium, scribing promptly makes the wide-angle silicon luminous-power distributor after the end face polishing.

This technology obtains the great-angle Y-branch silicon luminous-power distribution that angle is 8 degree according to design Device. The advantage of this preparation method is:

1, the back side positive etching of mixing has reduced the doping of great-angle Y-branch luminous-power distributor The degree of depth.

2, adopt glass substrate good to the restriction effect of light.

Claims

1, a kind of method for making of great-angle Y-branch silicon luminous-power distributor, it is characterized in that its adopts silicon to make ducting layer, glass is made limiting layer, the making of silicon waveguide is the one side doping another side lithographic technique that adopts silicon chip, and after mixing on the silicon chip silicon chip mixed earlier face and glass are good for and are closed and adopt double face photoetching machine that ducting layer is carried out the technology of dual surface lithography and make.

2, the method for making of great-angle Y-branch silicon luminous-power distributor according to claim 1 is characterized in that it comprises the following steps:

(1) graphical window of making doped region on silicon chip, at first thermal oxide layer of silicon dioxide on the silicon chip of twin polishing makes the doping window then by lithography, uses the hydrofluorite corrode silicon dioxide, obtains the window that mixes;

(2) expand boron, give deposit earlier, distribute again, remove Pyrex with hydrofluorite;

(3) silicon chip doping face and glass bonding, the expansion boron doping face bonding of the polished surface of glass and silicon chip, its condition is:

Bonding temperature 300-400 ℃

Bonding voltage 800-1600 volt;

(4) wafer thinning is used chemical corrosion, or galvanic corrosion, or the method for mechanical buffing or its combination with wafer thinning to required thickness;

(5) make the aluminium mask, evaporation of aluminum on silicon face, aluminum layer thickness is the 2000-4000 dust;

(6) dual surface lithography is made the waveguide figure, utilizes double face photoetching machine that ducting layer is carried out dual surface lithography, goes out waveguide graphical window with phosphoric acid corrosion after the photoetching;

(7) corrode or etch ridge waveguide;

(8) remove aluminium, scribing can make after the end face polishing.

3, the method for making of great-angle Y-branch luminous-power distributor according to claim 2 is characterized in that the technology of described wafer thinning is:

(1) behind the bonding, 60 ℃ of corrosion, also remains about 40 microns up to silicon chip with 50% potassium hydroxide solution;

(2) with mechanical polishing method with wafer thinning to desired thickness.