EP1233927A1 - Appareil et procede de formation d'une membrane a pores a l'echelle nanometrique - Google Patents
Appareil et procede de formation d'une membrane a pores a l'echelle nanometriqueInfo
- Publication number
- EP1233927A1 EP1233927A1 EP00980528A EP00980528A EP1233927A1 EP 1233927 A1 EP1233927 A1 EP 1233927A1 EP 00980528 A EP00980528 A EP 00980528A EP 00980528 A EP00980528 A EP 00980528A EP 1233927 A1 EP1233927 A1 EP 1233927A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- base layer
- sacrificial
- etch stop
- membrane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 70
- 239000011148 porous material Substances 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 36
- 239000000758 substrate Substances 0.000 claims abstract description 23
- 239000010410 layer Substances 0.000 claims description 134
- 238000009792 diffusion process Methods 0.000 claims description 31
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 29
- 239000008103 glucose Substances 0.000 claims description 29
- 102000009027 Albumins Human genes 0.000 claims description 21
- 108010088751 Albumins Proteins 0.000 claims description 21
- 239000011241 protective layer Substances 0.000 claims description 14
- 238000012360 testing method Methods 0.000 claims description 13
- 229910052710 silicon Inorganic materials 0.000 claims description 11
- 239000010703 silicon Substances 0.000 claims description 11
- 238000005530 etching Methods 0.000 claims description 9
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 8
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 8
- 238000005498 polishing Methods 0.000 claims description 3
- 238000000059 patterning Methods 0.000 claims 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 10
- 150000004767 nitrides Chemical class 0.000 description 8
- 238000012545 processing Methods 0.000 description 8
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 7
- 229920005591 polysilicon Polymers 0.000 description 7
- 238000011160 research Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000000151 deposition Methods 0.000 description 5
- 230000007717 exclusion Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 102000004169 proteins and genes Human genes 0.000 description 5
- 108090000623 proteins and genes Proteins 0.000 description 5
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 4
- 229910052796 boron Inorganic materials 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000010420 art technique Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 238000001459 lithography Methods 0.000 description 2
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000008363 phosphate buffer Substances 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 230000001225 therapeutic effect Effects 0.000 description 2
- -1 titanium) Chemical class 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000011101 absolute filtration Methods 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 239000000560 biocompatible material Substances 0.000 description 1
- 239000013060 biological fluid Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- LOKCTEFSRHRXRJ-UHFFFAOYSA-I dipotassium trisodium dihydrogen phosphate hydrogen phosphate dichloride Chemical compound P(=O)(O)(O)[O-].[K+].P(=O)(O)([O-])[O-].[Na+].[Na+].[Cl-].[K+].[Cl-].[Na+] LOKCTEFSRHRXRJ-UHFFFAOYSA-I 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007824 enzymatic assay Methods 0.000 description 1
- XJRPTMORGOIMMI-UHFFFAOYSA-N ethyl 2-amino-4-(trifluoromethyl)-1,3-thiazole-5-carboxylate Chemical compound CCOC(=O)C=1SC(N)=NC=1C(F)(F)F XJRPTMORGOIMMI-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000006377 glucose transport Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000000338 in vitro Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000001393 microlithography Methods 0.000 description 1
- 230000004660 morphological change Effects 0.000 description 1
- 239000002773 nucleotide Substances 0.000 description 1
- 125000003729 nucleotide group Chemical group 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 210000003463 organelle Anatomy 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002953 phosphate buffered saline Substances 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005597 polymer membrane Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 210000003370 receptor cell Anatomy 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 210000001519 tissue Anatomy 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
- B81C1/00158—Diaphragms, membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0053—Inorganic membrane manufacture by inducing porosity into non porous precursor membranes
- B01D67/0058—Inorganic membrane manufacture by inducing porosity into non porous precursor membranes by selective elimination of components, e.g. by leaching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0053—Inorganic membrane manufacture by inducing porosity into non porous precursor membranes
- B01D67/006—Inorganic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods
- B01D67/0062—Inorganic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods by micromachining techniques, e.g. using masking and etching steps, photolithography
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0072—Inorganic membrane manufacture by deposition from the gaseous phase, e.g. sputtering, CVD, PVD
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/0215—Silicon carbide; Silicon nitride; Silicon oxycarbide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/022—Metals
- B01D71/0221—Group 4 or 5 metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/0283—Pore size
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/04—Characteristic thickness
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/08—Patterned membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/06—Bio-MEMS
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/10—Microfilters, e.g. for gas or fluids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2201/00—Manufacture or treatment of microstructural devices or systems
- B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
- B81C2201/0101—Shaping material; Structuring the bulk substrate or layers on the substrate; Film patterning
- B81C2201/0102—Surface micromachining
- B81C2201/0105—Sacrificial layer
- B81C2201/0109—Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2201/00—Manufacture or treatment of microstructural devices or systems
- B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
- B81C2201/0101—Shaping material; Structuring the bulk substrate or layers on the substrate; Film patterning
- B81C2201/0128—Processes for removing material
- B81C2201/013—Etching
- B81C2201/0135—Controlling etch progression
- B81C2201/014—Controlling etch progression by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2201/00—Manufacture or treatment of microstructural devices or systems
- B81C2201/05—Temporary protection of devices or parts of the devices during manufacturing
- B81C2201/053—Depositing a protective layers
Definitions
- This invention relates generally to membranes with nanometer scale pores that may be used in filtering applications More particularly, this invention relates to the use of micro fab ⁇ cation processing techniques to form nanometer scale porous membranes
- the invention includes a filter comprising a membrane of elemental silicon with sub-fifty nanometer pores formed within it.
- the membrane has a glucose diffusion test result of at least 1 mg/dl and an albumin diffusion test result of at most 0.1 g/dl.
- the filter has a substrate, a buried sacrificial etch stop layer positioned on the substrate, with the membrane positioned on the buried sacrificial etch stop layer.
- the buried sacrificial etch stop layer is silicon nitride.
- the method of the invention includes forming a membrane with nanometer scale pores.
- a sacrificial etch stop layer is formed on a substrate.
- a base layer is constructed on the sacrificial etch stop layer.
- Micrometer scale pores are formed within the base layer.
- a sacrificial base layer is built on the base layer. The sacrificial base layer is removed from selected regions of the base layer to define nanometer scale pores within the base layer.
- FIGURE 1 illustrates a substrate with a sacrificial buried layer formed thereon in accordance with an embodiment of the invention.
- FIGURE 2 illustrates a base layer formed on the sacrificial buried layer of Figure 1.
- FIGURE 3 illustrates etched micrometer pores formed within a base layer and stopped by a sacrificial buried layer in accordance with the invention.
- FIGURE 4 illustrates the deposition of a sacrificial base layer in accordance with an embodiment of the invention.
- FIGURE 5 illustrates anchors formed in the sacrificial base layer utilized in accordance with the invention.
- FIGURE 6 illustrates a plug layer formed in accordance with an embodiment of the invention.
- FIGURE 7 illustrates the plug layer after mechanical polishing in accordance with an embodiment of the invention.
- FIGURE 8 illustrates a protective layer and resultant selective etching utilized in accordance with an embodiment of the invention.
- FIGURE 9 illustrates a fully released nanometer scale membrane after removal of the protective layers, and selective regions of the sacrificial buried layer.
- FIGURE 10 illustrates processing steps used to construct the devices of Figures 1-9.
- FIGURE 11 illustrates a device used to test the membrane of the invention.
- FIGURE 12 illustrates glucose diffusion through three different nanopore membranes.
- FIGURE 13 illustrates diffusion of glucose and albumin through micromachined nanopore membranes.
- FIGURE 14 illustrates glucose diffusion through micromachined membranes incubated in pure glucose and mixed glucose/albumin solutions.
- FIGURE 15 illustrates diffusion through millipore membranes incubated in pure glucose and mixed glucose/albumin solutions.
- FIGURE 16 is a table illustrating diffusion of Albumin through various membranes. Like reference numerals refer to corresponding parts throughout the drawings.
- the present invention relies upon many prior art techniques in forming a membrane with nanometer scale pores. However, the invention also departs from the prior art in several key respects. These departures from the prior art facilitate the formation of pores less than 50 nanometer.
- the technique of the invention relies upon a buried sacrificial etch stop layer.
- the buried sacrificial etch stop layer may be silicon nitride.
- the buried sacrificial etch stop layer operates as an etch stop, and is then removed to expose the nanopores of the invention.
- a buried sacrificial etch stop layer as an etchant stop during the formation of nanometer scale pores is believed to be novel. While buried etch stop layers are used for structural purposes in the prior art, it is not believed that the prior art shows or suggests the formation of a buried etch stop layer, which operates as an etchant stop during the formation of pores, and which is subsequently etched away to expose pores.
- the buried sacrificial etch stop layer facilitates three-dimensional control of the pore structure.
- Prior art techniques endeavored to control pore structure by balancing the etching of two different layers.
- the buried sacrificial etch stop technique of the invention facilitates the formation of pores less than 50 nanometers. Moreover, these pores can be uniformly formed across the entire wafer.
- the buried sacrificial etch stop layer of the invention eliminates the prior art use of diffused boron.
- diffused boron is used as an etch stop it provides an imprecise membrane depth.
- boron introduces stresses into the completed membrane.
- the buried sacrificial etch stop layer of the invention provides absolute etching selectivity, as the layer will not be etched at all by the disclosed KOH etchant. In contrast, boron will be minimally etched in the presence of a KOH etchant.
- the technique of the invention departs from prior art techniques in another important manner. Namely, the technique of the invention relies upon planarization of the outer structural layer to expose the total pore area, instead of the prior art approach of etching entrance holes in the top layer.
- the first step in the fabrication protocol is to etch a support ridge structure into a substrate. This is accomplished by simply etching a ridge structure prior to the deposition of the etch stop layer.
- the ridge provides mechanical rigidity to the subsequently formed membrane structure.
- the buried sacrificial etch stop layer is then deposited on the substrate.
- a low stress silicon nitride LSN or nitride
- LPCVD low pressure chemical vapor depositions
- 0.4 ⁇ m of silicon nitride was used.
- Figure 1 illustrates a substrate 20 with a sacrificial etch stop layer 22 formed thereon.
- the base structural layer (base layer) of the membrane is deposited on top of the stop layer 22. Because the stop layer 22 is thin, the structural layer is deposited down into the support ridges formed in the substrate 20. In one embodiment, 5 ⁇ m of polysilicon is used as the base layer.
- Figure 2 illustrates the base layer 24 positioned on the stop layer 22. Low stress silicon nitride may also be used as the base layer, in which case it operates as its own etch stop layer.
- the next processing step is to etch holes in the base layer 24 to define the shape of the pores.
- Prior art masks may be used to define the pores.
- the holes may be etched through the polysilicon by chlorine plasma, with a thermally grown oxide layer used as a mask.
- the buried sacrificial etch stop layer 22 acts as an etch stop for the plasma etching of a silicon base layer 24.
- Figure 3 illustrates the result of this processing.
- the figure illustrates holes 26 formed in the base layer 24, but terminating in the buried sacrificial etch stop layer 22. At this stage, the holes 26 define micrometer scale pores.
- Pore sacrificial oxide is subsequently grown on the base layer 24.
- Figure 4 illustrates a sacrificial oxide 28 positioned on the base layer 24.
- This sacrificial oxide 28 is also referred to as a nanometer scale sacrificial base layer or sacrificial base layer.
- This sacrificial base layer 28 is used to define nanometer scale pores.
- the thickness of the sacrificial base layer 28 determined the pore size in the final membrane, so control of this step is critical to reproducible membranes. This is accomplished by the thermal oxidation of the base layer 24 (e.g., a growth temperature of between 850-950° for approximately one hour with a ten minute anneal). Naturally, many techniques may be used to form a controlled thickness sacrificial base layer. For example, a thermally evaporated tungsten film can be used as a sacrificial base layer for polymer membranes and selectively removed with hydrogen peroxide.
- the basic requirement of the sacrificial base layer 28 is the ability to control the thickness with high precision across the entire wafer.
- a plug structural layer is subsequently deposited to file in the holes 26. This step has been implemented by depositing 1.5 ⁇ m of polysilicon.
- the resultant plug layer 32 is shown in Figure 6.
- the plug layer 32 is planarzied down to the base layer, leaving the final structure with the plug layer only in the pore hole openings, as shown in Figure 7.
- the method of planarization depends on the material used as the plug material.
- For the hard micro- fabrication materials polysilicon and nitride
- chemical mechanical polishing was used for planarization.
- the other materials studied were roughly planarized using a plasma etch, with a quick wet chemical smoothing. This technique has the advantage that, assuming it is not etched by the plasma used, the base layer is not affected, but has the disadvantage of the need for controlled etch timing to avoid completely etching the plugs themselves.
- FIG. 8 illustrates a protective layer(s) 34.
- the requirements of the protective layer 34 are that it be impervious to the silicon etch (KOH for these studies) and that it be removed without removing the plug 32 or base 24 structural layers.
- a thin nitride layer is used as the protective layer (nitride is not etched at all by KOH and dissolves slowly in HF).
- silicone is used as a protective layer, due to the processing temperature necessary for nitride deposition. (835° C).
- FIG. 8 illustrates the resultant aperture 36 formed in the substrate 20.
- each hole 26 defines a nanometer scale pore, with the sacrificial base layer 28 providing aperture size control.
- Figure 10 summarizes the foregoing processing steps.
- Figure 10 illustrates that the first processing step is to form a buried sacrificial etch stop layer on a substrate (step 50).
- a base layer is then constructed on the etch stop layer (step 52).
- Micrometer scale pores are then etched through the base layer to the etch stop layer (step 54).
- a sacrificial base layer is then deposited on the base layer (step 56).
- Anchors are then patterned in the sacrificial base layer (step 58).
- a plug layer is then formed on the base layer (step 60).
- the plug layer is subsequently planarized (step 62) and polished (step 64).
- Protective layers are then formed on the base layer and substrate (step 66).
- the protective layers are then selectively etched to form an aperture in the substrate (step 68).
- the protective layer, plug layer, and portions of the buried sacrificial etch stop layer are then released (step 70) in the manner described above.
- a membrane 40 (with 24.5 nanometer pore size +/- 0.9 nm) of the invention was compared with porous alumina (i.e., a WHATMAN ANODISC membrane with a pore size of .02 microns) and a mixed celluose acetate and nitrate membrane (i.e., a MILLIPORE ISOPORE with a pore size of 0.025 microns). All membranes were examined in vitro by measuring relative concentrations of glucose on both sides of the micro fabricated interface over time, using a mini diffusion chamber constructed around the membranes, as shown in Figure 11.
- Figure 11 illustrates a chamber 80 with a first compartment 82 and a second compartment 84 with fixed volumes of 2 ml. Sampling ports 86 are provided in each compartment. The compartments are at least partially separated by the desired membrane 90. Preferably, the two compartments are sealed with o-rings and are screwed together.
- Glucose is measured on either side of the membrane 90 using the diffusion chamber by means of a quantitative enzymatic assay (e.g., TRINDER, SIGMA) and colorometric reading via a spectrophotometer.
- a quantitative enzymatic assay e.g., TRINDER, SIGMA
- Samples of 0.1 ml were taken from the diffusion chamber and 10 ul of that were added to 3 ml of glucose reagent in a cuvette, and were mixed gently by inversion. Each tube was incubated for 18 minutes at room temperature and then readings were taken at a wavelength of 505 nm.
- the reagent is linear up to 750 mg/dl.
- the diffusion chamber itself was attached to a motor for stirring in order to minimize boundary layer effects (diffusion resistance at the liquid/membrane interface).
- the receptor cell was first filled with phosphate buffer saline for fifteen minutes before the filling of the donor cell.
- the donor cell was filled with solutions of glucose in phosphate buffer saline in varying concentrations. These tests were carried out at 37°C.
- the foregoing results illustrate glucose diffusion test results of at least 1 mg/dl in 330 minutes.
- the membrane has an albumin diffusion test result of at most 0.1 g/dl in 330 minutes.
- microfabricated silicon membranes were characterized in terms of glucose diffusion, albumin exclusion and stability in biological environments. Results indicated that glucose does indeed diffuse through microfabricated membranes at a rate comparable to commercially available membranes. At the same time, albumin is excluded from passage. In a mixed solution of glucose and albumin, it has been shown that only glucose diffuses through the membranes. Although several membranes, such as those by WHATMAN and MILLIPORE are available for absolute filtration, these membranes do not have all the desired "ideal" membrane properties, such as stability, bio-compatibility, and well-controlled perm-selectivity.
- the filter technology of the invention alleviates several of the problems associated with current commercially available separation membranes.
- membranes can be fabricated with sufficient precision to guarantee high pore uniformity in sub-micron dimensions.
- the thickness of the thermally grown oxide can be controlled to +/- lnm for nominal pore sizes as small as 18nm. This is the size range needed to obtain absolute protein exclusion and glucose diffusion for biosensor applications.
- this filter technology can bring in the added advantages of stability, minimal protein adsorption through established silicon surface modification techniques, reusability, and sterilizability.
- the invention has been disclosed in connection with fabricated elemental silicon.
- the techniques of the invention may also be used in connection with other bio-compatible materials, such as metals (e.g., titanium), ceramics (e.g., silica or silicon nitride), and polymers (e.g., polytetrafluorethylene, polymethylmethacrylate, polystyrenes, and silicones).
- metals e.g., titanium
- ceramics e.g., silica or silicon nitride
- polymers e.g., polytetrafluorethylene, polymethylmethacrylate, polystyrenes, and silicones.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16604999P | 1999-11-17 | 1999-11-17 | |
US166049P | 1999-11-17 | ||
PCT/US2000/031749 WO2001036321A1 (fr) | 1999-11-17 | 2000-11-17 | Appareil et procede de formation d"une membrane a pores a l"echelle nanometrique |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1233927A1 true EP1233927A1 (fr) | 2002-08-28 |
EP1233927A4 EP1233927A4 (fr) | 2003-01-08 |
Family
ID=22601590
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00980528A Withdrawn EP1233927A4 (fr) | 1999-11-17 | 2000-11-17 | Appareil et procede de formation d'une membrane a pores a l'echelle nanometrique |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1233927A4 (fr) |
JP (1) | JP2003514677A (fr) |
AU (1) | AU1778101A (fr) |
WO (1) | WO2001036321A1 (fr) |
Families Citing this family (23)
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EP1432500B1 (fr) * | 2001-10-02 | 2007-03-07 | Sophion Bioscience A/S | Pompe a ecoulement electroosmotique a tamis |
US7037082B2 (en) | 2001-10-02 | 2006-05-02 | Sophion Bioscience A/S | Corbino disc electroosmotic flow pump |
FR2844725B1 (fr) * | 2002-09-24 | 2005-01-07 | Commissariat Energie Atomique | Procede de fabrication d'une membrane biomimetique, membrane biomimetique et ses applications |
US7578954B2 (en) * | 2003-02-24 | 2009-08-25 | Corium International, Inc. | Method for manufacturing microstructures having multiple microelements with through-holes |
DE10353894B4 (de) * | 2003-07-11 | 2007-02-15 | Nft Nanofiltertechnik Gmbh | Filterelement und Verfahren zu dessen Herstellung |
US7632406B2 (en) * | 2004-04-20 | 2009-12-15 | Lawrence Livermore National Security, Llc | Smart membranes for nitrate removal, water purification, and selective ion transportation |
NL1026530C2 (nl) * | 2004-06-30 | 2006-01-02 | Friesland Brands Bv | Membraan op drager, alsmede werkwijze ter vervaardiging van een dergelijk membraan. |
US20080248182A1 (en) * | 2004-05-03 | 2008-10-09 | Tjeerd Jongsma | Device with a Membrane on a Carrier, as Well as a Method for Manufacturing Such a Membrane |
EP1874443A4 (fr) * | 2005-04-29 | 2009-09-16 | Univ Rochester | Membranes nanoporeuses ultrafines, procede de fabrication et leurs utilisations |
EP1721657A1 (fr) * | 2005-05-13 | 2006-11-15 | SONY DEUTSCHLAND GmbH | Méthode de fabrication d'une membrane polymère ayant au moins un pore |
EP2146689B1 (fr) | 2007-04-16 | 2020-08-12 | Corium, Inc. | Réseaux de micro-aiguilles coulées dans un solvant contenant un actif |
WO2009048607A1 (fr) | 2007-10-10 | 2009-04-16 | Corium International, Inc. | Distribution de vaccin par l'intermédiaire de réseaux de micro-aiguilles |
CA2798145C (fr) | 2010-05-04 | 2022-10-18 | Corium International, Inc. | Methode et dispositif permettant l'administration transdermique d'hormone parathyroidienne au moyen d'un reseau de microprojections |
EP2517779A1 (fr) * | 2011-04-26 | 2012-10-31 | Nederlandse Organisatie voor toegepast -natuurwetenschappelijk onderzoek TNO | Membrane composite de nanopores |
AU2013364053B2 (en) | 2012-12-21 | 2018-08-30 | Corium Pharma Solutions, Inc. | Microarray for delivery of therapeutic agent and methods of use |
CN105142711B (zh) | 2013-03-12 | 2019-01-22 | 考里安国际公司 | 微突起施加器 |
JP6689187B2 (ja) | 2013-03-15 | 2020-04-28 | コリウム, インコーポレイテッド | 複数の衝突微小突起アプリケータおよび使用方法 |
US10384045B2 (en) | 2013-03-15 | 2019-08-20 | Corium, Inc. | Microarray with polymer-free microstructures, methods of making, and methods of use |
JP2016512754A (ja) | 2013-03-15 | 2016-05-09 | コリウム インターナショナル, インコーポレイテッド | 治療剤の送達のためのマイクロアレイ、使用方法および製造方法 |
CA2906541C (fr) | 2013-03-15 | 2022-06-21 | Corium International, Inc. | Microreseau pour l'administration d'un agent therapeutique et ses procedes d'utilisation |
US10624843B2 (en) | 2014-09-04 | 2020-04-21 | Corium, Inc. | Microstructure array, methods of making, and methods of use |
US10857093B2 (en) | 2015-06-29 | 2020-12-08 | Corium, Inc. | Microarray for delivery of therapeutic agent, methods of use, and methods of making |
JP7417545B2 (ja) * | 2018-05-18 | 2024-01-18 | ザ リージェンツ オブ ザ ユニバーシティ オブ カリフォルニア | 生体内血液濾過膜およびデバイス |
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US5938923A (en) * | 1997-04-15 | 1999-08-17 | The Regents Of The University Of California | Microfabricated filter and capsule using a substrate sandwich |
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2000
- 2000-11-17 WO PCT/US2000/031749 patent/WO2001036321A1/fr not_active Application Discontinuation
- 2000-11-17 AU AU17781/01A patent/AU1778101A/en not_active Abandoned
- 2000-11-17 JP JP2001538280A patent/JP2003514677A/ja not_active Withdrawn
- 2000-11-17 EP EP00980528A patent/EP1233927A4/fr not_active Withdrawn
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US5798042A (en) * | 1994-03-07 | 1998-08-25 | Regents Of The University Of California | Microfabricated filter with specially constructed channel walls, and containment well and capsule constructed with such filters |
US5948255A (en) * | 1994-03-07 | 1999-09-07 | The Regents Of The University Of California | Microfabricated particle thin film filter and method of making it |
US5919364A (en) * | 1996-06-24 | 1999-07-06 | Regents Of The University Of California | Microfabricated filter and shell constructed with a permeable membrane |
US6405066B1 (en) * | 2000-03-17 | 2002-06-11 | The Regents Of The University Of California | Implantable analyte sensor |
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"PROCESS FOR PRODUCING A PRECISION FILTER" IBM TECHNICAL DISCLOSURE BULLETIN, IBM CORP. NEW YORK, US, vol. 32, no. 4A, 1 September 1989 (1989-09-01), pages 126-127, XP000040003 ISSN: 0018-8689 * |
DESAI T A ET AL: "Characterization of micromachined silicon membranes for immunoisolation and bioseparation applications" JOURNAL OF MEMBRANE SCIENCE, ELSEVIER SCIENCE, AMSTERDAM, NL, vol. 159, no. 1-2, 1 July 1999 (1999-07-01), pages 221-231, XP004169176 ISSN: 0376-7388 * |
DESAI T A ET AL: "Micromachined interfaces: new approaches in cell immunoisolation and biomolecular separation" BIOMOLECULAR ENGINEERING, ELSEVIER, NEW YORK, NY, US, vol. 17, no. 1, October 2000 (2000-10), pages 23-36, XP004257822 ISSN: 1389-0344 * |
See also references of WO0136321A1 * |
Also Published As
Publication number | Publication date |
---|---|
JP2003514677A (ja) | 2003-04-22 |
WO2001036321A1 (fr) | 2001-05-25 |
EP1233927A4 (fr) | 2003-01-08 |
AU1778101A (en) | 2001-05-30 |
WO2001036321A9 (fr) | 2002-07-04 |
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