Form the method for optical table
Technical field
The present invention relates to technical field of semiconductors, relate in particular to the method that forms optical table.
Background technology
(Si Optical Bench, SiOB) system are the integrated optical element platforms of a kind of height to the silicon optical table.LED (lighting emitting diode) more and more attract people's attention, and LED is applied in also on the silicon optical table, is used to provide light source because it has low in power consumption.In order to improve the luminous efficiency that is applied in the LED on the silicon optical table, prior art forms groove on the silicon optical table, led chip is arranged in the groove, utilizes the secondary optics efficient of the optically focused effect lifting LED of groove.
Fig. 1 a~Fig. 1 f is the cross-sectional view of the method for the groove on the formation silicon optical table of prior art, and with reference to figure 1a~Fig. 1 f, the method for the groove on the formation silicon optical table of prior art comprises:
With reference to figure 1a, silicon substrate 10 is provided, the said silicon substrate 10 of thermal oxidation; Surface at said silicon substrate 10 forms silica 11; Said surface comprises upper surface, lower surface and four sides, owing to be profile, only illustrates two sides among the figure; And because accompanying drawing is the part of silicon substrate 10, so do not illustrate the silicon dioxide of side.
With reference to figure 1b; Upper surface at said silica 11 forms the first patterned photoresist layer 121; Photoresist layer 122, the first patterned photoresist layers 121 of lower surface formation second graphical define the figure of groove, and the photoresist layer 122 of second graphical defines the figure of through hole.
With reference to figure 1c, the silicon dioxide that utilizes buffer oxide silicon etch solution (BOE) etching not covered by the photoresist layer 122 of the first patterned photoresist layer 121 and second graphical.Remove the photoresist layer 122 of the first patterned photoresist layer 121 and second graphical afterwards.
With reference to figure 1d, the silicon substrate 10 that utilizes potassium hydroxide (KOH) solution etching not covered by silica 11 forms groove 13, the through hole 15 of device mesa 14 and device mesa 14 both sides.Wherein, device mesa 14 is used to be provided with LED, and groove 13 can promote the secondary optics efficient of LED as the optically focused bucket, and through hole 15 can be used for being provided with radiating tube, is used for the heat radiation of LED.
With reference to figure 1e; The said silicon substrate 10 of thermal oxidation forms silica 1 11 at the sidewall of through hole 15, thereby on all surfaces of whole silicon substrate; The sidewall, the bottom that comprise groove 13; The sidewall of through hole 15 and the upper and lower surfaces of silicon substrate, side all are formed with silicon dioxide, this silicon dioxide as dielectric layer after during plated metal, silicon substrate 10 and metal are isolated.
Ginseng Fig. 1 f; In the sidewall of groove 13 and bottom, the sidewall of through hole 15, the upper and lower surfaces plated metal of silicon substrate 10; Form metallic film 16, the technology that this metallic film 16 can be used for is afterwards carried out etching formation metal line, as the interconnection line between the electronic component.
Yet; The method that above-described method forms the groove in the silicon optical table forms for utilizing KOH solution to carry out wet etching, and the bottom of the groove of formation and the angle of sidewall are about 54.7 °, when forming a groove; This angle can well promote the secondary optics efficient of LED; But when forming a plurality of groove, when in a plurality of grooves, respectively LED being set, this angular range can not well promote the secondary optics efficient of LED.Owing to use wet etching to form groove, the angle that can not regulate the groove of formation when therefore in a plurality of grooves, LED being set, also just can not be optimized the secondary optics efficient of LED.
On February 2nd, 2005, disclosed application number disclosed a kind of manufacture method of optical table for the one Chinese patent application of " 200410048116.9 ", yet did not also solve above-described technical problem.
Summary of the invention
The problem that the present invention solves is the method for groove of the formation optical table of prior art, and the angle that can not regulate groove causes to form a plurality of grooves, when in a plurality of grooves, LED being set, can not optimize the secondary optics efficient of LED.
For addressing the above problem, the present invention provides a kind of method that forms optical table, comprising:
Substrate is provided;
Utilize the said substrate of dry etching figureization, form groove;
The said patterned substrate of oxidation for the first time forms oxide-film on the surface of patterned substrate and the surface of groove;
The substrate of graphical said bottom portion of groove and oxide-film, the through hole of formation device mesa, device mesa both sides;
The said substrate of oxidation for the second time is at the sidewall formation oxide-film of said through hole;
Plated metal covers the oxide-film of said substrate top surface, lower surface, bottom portion of groove and sidewall and through-hole side wall.
Optional, said substrate is a silicon substrate, said oxide-film is a silicon dioxide.
Optional, the said said substrate of dry etching figureization that utilizes forms groove and comprises:
Upper surface at said substrate forms photoresist layer;
Graphical said photoresist layer defines the figure of groove;
With said patterned photoresist layer is the said substrate of mask dry etching, forms groove;
Remove remaining photoresist.
Optional, the gas that said dry etching uses comprises: SF
6, HCL.
Optional, the angle that the sidewall of said groove departs from the bottom surface is 100 °~135 °.
Optional, the gas that said dry etching uses comprises: SF
6, C
4F
8
Optional, the angle that the sidewall of said groove departs from the bottom surface is 90 °~115 °.
Optional, the method that the said first time, oxidation was used is thermal oxidation.
Optional, the method that the said second time, oxidation was used is thermal oxidation.
Optional, the substrate of said graphical said bottom portion of groove and oxide-film, the through hole that forms device mesa, device mesa both sides comprises;
On the oxide-film of the oxide-film of said bottom portion of groove and sidewall and substrate top surface, form first photoresist layer, form second photoresist layer on the oxide-film of substrate lower surface;
Graphical said first photoresist layer and second photoresist layer form the photoresist layer of the first patterned photoresist layer and second graphical, on the photoresist layer of the said first patterned photoresist layer and second graphical, define the figure of through hole;
Photoresist layer with the said first patterned photoresist layer and second graphical is a mask, and the oxide-film of the substrate of the said bottom portion of groove of first wet etching and oxide-film, substrate lower surface forms patterned oxide-film;
Remove the photoresist layer of the first patterned photoresist layer and second graphical;
Second wet etching is removed the substrate that not graphical oxide-film covers, and forms the through hole of device mesa, device mesa both sides.
Optional, the solution that said first wet etching uses is the buffer oxide silicon etch solution.
Optional, the solution that said second wet etching uses is potassium hydroxide solution.
Optional, said metal is selected from Au, Pt, Ti one of them or theys' combination in any.
Optional, said deposition process is sputter.
Compared with prior art, the present invention has the following advantages:
Utilization of the present invention is dry-etched in and forms groove in the substrate, just forms the groove in the optical table, can be through the pressure of gas in the adjustment dry etching; The sidewall of the groove that adjustment forms and the angle of bottom, thus can select the sidewall of suitable groove and the angle of bottom through selecting suitable pressure; When in a plurality of grooves, LED being set; Optimize the secondary optics efficient of LED, just reduce the loss of the light energy of LED, save the energy.
Description of drawings
Fig. 1 a~Fig. 1 f is the cross-sectional view of the method for the groove on the formation silicon optical table of prior art;
Fig. 2 is the flow chart of formation optical table of the present invention;
Fig. 3 a~Fig. 3 h is the cross-sectional view of the formation optical table of the embodiment of the invention;
Fig. 4 is the vertical view of the optical table of a plurality of grooves of formation.
Embodiment
The method of the formation optical table of the specific embodiment of the invention is utilized to be dry-etched in to form groove in the substrate, just forms the groove in the optical table; Can be through the pressure of gas in the adjustment dry etching; The sidewall of the groove that adjustment forms and the angle of bottom, thus can select the sidewall of suitable groove and the angle of bottom through selecting suitable pressure; When in a plurality of grooves, LED being set; Optimize the secondary optics efficient of LED, just reduce the loss of the light energy of LED, save the energy.
In order to make those skilled in the art can better understand the present invention, specify embodiment of the present invention below in conjunction with accompanying drawing.
Fig. 2 is the flow chart of formation optical table of the present invention, and with reference to figure 2, the method for the formation optical table of the specific embodiment of the invention comprises: comprising:
Step S21 provides substrate;
Step S22 utilizes the said substrate of dry etching figureization, forms groove;
Step S23, the said patterned substrate of oxidation for the first time forms oxide-film on the surface of patterned substrate and the surface of groove;
Step S24, the substrate of graphical said bottom portion of groove and oxide-film, the through hole of formation device mesa, device mesa both sides;
Step S25, the said substrate of oxidation for the second time is at the sidewall formation oxide-film of said through hole;
Step S26, plated metal, the oxide-film of covering substrate top surface, lower surface, bottom portion of groove and sidewall and through-hole side wall.
Fig. 3 a~Fig. 3 h is the cross-sectional view of the formation optical table of the embodiment of the invention; In order to make those skilled in the art can better understand the method for the formation optical table of the specific embodiment of the invention, also combine method referring to figs. 2 and 3 the formation optical table of a~Fig. 3 h detailed description specific embodiment of the invention below in conjunction with specific embodiment.
In conjunction with referring to figs. 2 and 3 a, execution in step S21 provides substrate 30.The material of said substrate 30 can be the silicon or the SiGe of monocrystalline or non crystalline structure for material.In the specific embodiment of the invention, the material of said substrate 30 is a silicon, and promptly substrate 30 is a silicon substrate.
In conjunction with referring to figs. 2 and 3 c, execution in step S22 utilizes the said substrate 30 of dry etching figureization, forms groove 32.In the specific embodiment of the invention, the said said substrate 30 of dry etching figureization that utilizes forms groove 32 and comprises: with reference to figure 3b, form photoresist layer at said substrate 30 upper surfaces; Graphical said photoresist layer forms patterned photoresist layer 31, defines the figure of groove; With reference to figure 3c, be the said substrate of mask dry etching with said patterned photoresist layer, form groove 32; Remove remaining photoresist.
Specify the method for the formation groove of the specific embodiment of the invention below:
With reference to figure 3b, form photoresist layer at said substrate 30 upper surfaces; Graphical said photoresist layer forms patterned photoresist layer 31, defines the figure of groove.In the specific embodiment of the invention; The method that forms photoresist can be spraying process; Drop-coating and spin-coating method etc. in the specific embodiment of the invention, select for use spin-coating method on the upper surface of substrate 30, to form photoresist layer; Utilize exposure, the graphical photoresist layer of developing process then, form patterned photoresist layer 31.
With reference to figure 3c, be the said substrate 30 of mask dry etching with said patterned photoresist layer, form groove 32, remove remaining photoresist then.In the specific embodiment of the invention, the gas that dry etching uses comprises: sulphur hexafluoride (SF
6) gas, hydrogen chloride (HCl) gas, when forming groove 32 with this type gas etching substrate, the sidewall of said groove 32 and the angle d between the bottom surface are 45 °~80 °, that is to say, the angle D that the sidewall of groove 32 departs from the bottom surface is 100 °~135 °.Can be through the pressure of the gas in the adjustment etch chamber, the sidewall of the groove that adjustment forms and the angle of bottom, wherein the scope of gas pressure intensity is at 5~200mTorr (millitorr).In another embodiment of the present invention, the gas that dry etching uses comprises: sulphur hexafluoride (SF
6) gas, perfluorobuttene (C
4F
8) gas; When forming groove 32 with this type gas etching substrate, the sidewall of groove 32 and the angle d between the bottom surface are 65 °~90 °, that is to say; The angle D that the sidewall of groove 32 departs from the bottom surface is 90 °~115 °; Can be through the pressure of the gas in the adjustment etch chamber, the sidewall of the groove 32 that adjustment forms and the angle of bottom, wherein the scope of gas pressure intensity is in 5~200mTorr (person of outstanding talent's holder).
With reference to the vertical view of figure 4, on substrate 30, form a plurality of grooves 32, in specific embodiment for the optical table of a plurality of grooves of formation; A plurality of grooves 32 are arranged in array, and can select optimum angle through the sidewall of adjustment groove and the angle of bottom; When in a plurality of grooves, LED being set; Optimize the secondary optics efficient of LED, just reduce the loss of the light energy of LED, save the energy.
In conjunction with referring to figs. 2 and 3 d, execution in step S23, the said patterned substrate 30 of oxidation for the first time forms oxide-film 33 on the surface of patterned substrate 30 and the surface of groove 32.Wherein, the surface of patterned substrate 30 is upper surface, lower surface and four sides (owing to for profile, only illustrating two sides among the figure) of substrate 30.Groove 32 surfaces comprise the bottom and the sidewall of groove 32.In the specific embodiment of the invention, the method that the said first time, oxidation was used is thermal oxidation, and the temperature of thermal oxidation is 1100 ℃.In the specific embodiment of the invention, the material of substrate 30 is a silicon, therefore on the surface of patterned substrate 30 and the oxide-film 33 that forms of the surface of groove be silicon dioxide.
In conjunction with referring to figs. 2 and 3 f, execution in step S24, graphical said groove 32 substrate of bottom portion 30 and oxide-films 33 form the through hole 37 of device mesa 36, device mesa both sides.In the specific embodiment of the invention; Said graphical said groove 32 substrate of bottom portion 30 and oxide-film 33; The through hole 37 that forms device mesa 36, device mesa 36 both sides comprises: with reference to figure 3e, and formation second photoresist layer on the oxide-film 33 of formation first photoresist layer, substrate 30 lower surfaces on the oxide-film 33 of the oxide-film 33 of said groove 32 bottoms and sidewall and substrate 30 upper surfaces; Graphical said first photoresist layer and second photoresist layer form the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical, on the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical, define the figure of through hole; With reference to figure 3f, be mask with the photoresist layer 35 of the said first patterned photoresist layer 34 and second graphical, the oxide-film 33 of said groove 32 substrate of bottom portion 30 of first wet etching and oxide-film 33, substrate 30 lower surfaces forms patterned oxide-film 33; Remove the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical; Second wet etching is removed the substrate 30 that not graphical oxide-film 33 covers, and forms the through hole 37 of device mesa 36, device mesa both sides.
Specify graphical said groove 32 substrate of bottom portion 30 and oxide-film 33 of the specific embodiment of the invention below, form the through hole 37 of device mesa 36, device mesa both sides:
With reference to figure 3e, on the oxide-film that forms first photoresist layer, substrate 30 lower surfaces on the oxide-film 33 of the oxide-film 33 of said groove 32 bottoms and sidewall and substrate 30 upper surfaces, form second photoresist layer; Graphical said first photoresist layer and second photoresist layer form the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical, at the figure that defines through hole on the oxide-film 33 of groove 32 bottoms and on the oxide-film 33 of substrate 30 lower surfaces.In the specific embodiment of the invention; The method that forms photoresist layer can be spraying process; Drop-coating and spin-coating method etc.; In the specific embodiment of the invention, on the oxide-film 33 that forms first photoresist layer, substrate 30 lower surfaces on the oxide-film 33 of the oxide-film 33 of said groove 32 bottoms and sidewall and substrate 30 upper surfaces, form second photoresist layer; Utilize exposure, the graphical first photoresist glue-line of developing process and second photoresist layer then, form the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical.
In conjunction with reference to figure 3f and Fig. 3 e; Photoresist layer 35 with the said first patterned photoresist layer 34 and second graphical is a mask; The oxide-film 33 of said groove 32 substrate of bottom portion 30 of first wet etching and oxide-film 33, substrate 30 lower surfaces forms patterned oxide-film 33; Remove the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical then; Second wet etching is removed the substrate 30 that not graphical oxide-film 33 covers, and forms the through hole 37 of device mesa 36, device mesa both sides.Device mesa 36 is used for being provided with LED, and through hole 37 has defined the formation position of radiating tube in the optical table, that is to say; Through hole 37 is used for forming radiating tube; The heat that the time distributes in illumination of LED can distribute through the radiating tube of both sides like this, can improve the useful life of LED like this.
In the specific embodiment of the invention; First wet etching is at first removed the oxide-film that is not covered by the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical; In the specific embodiment of the invention, for removing the silicon dioxide that is not covered by the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical; Afterwards, remove the photoresist layer 35 of the first patterned photoresist layer 34 and second graphical, remove the substrate 30 that not oxidized film 33 (being silicon dioxide in the specific embodiment of the invention) covers with second wet etching then.In the specific embodiment of the invention, the solution that said first wet etching uses is buffer oxide silicon etch solution (BOE); The solution that said second wet etching uses is potassium hydroxide (KOH) solution.
In conjunction with referring to figs. 2 and 3 g, execution in step S25, the said substrate 30 of oxidation for the second time forms oxide-film 371 at the sidewall of said through hole 37.In the specific embodiment of the invention, the said substrate 30 of oxidation for the second time is at the sidewall formation oxide-film 371 of through hole 37; And, owing in first time oxidizing process, on the surface of substrate 30, formed oxide-film; The said substrate 30 of oxidation for the second time can be thickeied the thickness of original oxidation 33 films.Because in the specific embodiment of the invention, substrate 30 is a silicon substrate, therefore in the oxidation second time, the oxide-film 371 that the sidewall of through hole 37 forms also is a silicon dioxide.Wherein, the method that oxidation is for the second time used is thermal oxidation, and oxidate temperature is 1100 ℃.Behind the execution of step S25; On all surfaces of entire substrate 30, comprise sidewall, the bottom of groove 32, upper and lower surfaces, the side of the sidewall of through hole 37 and substrate 30 all are formed with silicon dioxide; This silicon dioxide as dielectric layer after during plated metal, substrate 30 and metal are isolated.
In conjunction with referring to figs. 2 and 3 h, execution in step S26, plated metal 38 covers upper surface, lower surface, groove 32 bottoms and the sidewall of substrate 30 and the oxide-film of through hole 37 sidewalls.The technology that this metal 38 can be used for is afterwards carried out etching formation metal line, as the interconnection line between the electronic component.In the specific embodiment of the invention, said metal is selected from gold (Au), platinum (Pt), and titanium (Ti) one of them or theys' combination in any, for example, metal is selected from Au and Pt, then can deposit the formation layer of Au earlier, and then deposition forms one deck Pt.And said deposition process is sputter, utilizes sputter to deposit metal on the oxide-film of upper surface, lower surface, groove 32 bottoms and sidewall and through hole 37 sidewalls of substrate 30.
Though the present invention with preferred embodiment openly as above; But it is not to be used for limiting the present invention; Any those skilled in the art are not breaking away from the spirit and scope of the present invention; Can utilize the method and the technology contents of above-mentioned announcement that technical scheme of the present invention is made possible change and modification, therefore, every content that does not break away from technical scheme of the present invention; To any simple modification, equivalent variations and modification that above embodiment did, all belong to the protection range of technical scheme of the present invention according to technical spirit of the present invention.