NL2016329B1 - A method of manufacturing a plurality of through-holes in a layer of first material. - Google Patents

A method of manufacturing a plurality of through-holes in a layer of first material. Download PDF

Info

Publication number
NL2016329B1
NL2016329B1 NL2016329A NL2016329A NL2016329B1 NL 2016329 B1 NL2016329 B1 NL 2016329B1 NL 2016329 A NL2016329 A NL 2016329A NL 2016329 A NL2016329 A NL 2016329A NL 2016329 B1 NL2016329 B1 NL 2016329B1
Authority
NL
Netherlands
Prior art keywords
layer
base
probe
holes
ion beam
Prior art date
Application number
NL2016329A
Other languages
Dutch (nl)
Inventor
Sarajlic Edin
Original Assignee
Smarttip B V
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Smarttip B V filed Critical Smarttip B V
Priority to NL2016329A priority Critical patent/NL2016329B1/en
Priority to US15/444,010 priority patent/US10207244B2/en
Priority to EP17158208.3A priority patent/EP3210936B1/en
Priority to US15/444,086 priority patent/US9975761B2/en
Priority to EP17158214.1A priority patent/EP3210937B1/en
Application granted granted Critical
Publication of NL2016329B1 publication Critical patent/NL2016329B1/en

Links

Abstract

A method of manufacturing a plurality of through-holes in a layer of first material by subjecting part of the layer of said first material to ion beam milling. For batch-wise production, the method comprises - after a step of providing the layer of first material and before the step of ion beam milling, providing a second layer of a second material on the layer of first material, - providing the second layer of the second material with a plurality of holes, the holes being provided at central locations of pits in the first layer, and - subjecting the second layer of the second material to said step of ion beam milling at an angle using said second layer of the second material as a shadow mask.

Description

A method of manufacturing a plurality of through-holes in a layer of first material
The present invention relates to a method of manufacturing a plurality of through-holes in a layer of first material wherein an intermediate product is subjected to a plurality of method steps, the intermediate product - defining a first side and a second side, and - comprises a base substrate, said base substrate comprising a base material, wherein at the first side the surface of the base substrate defines a main plane; wherein the plurality of method steps comprises the steps of - providing the base substrate of the intermediate product at the first side with a plurality of pits in said base material, and - providing the base substrate with the layer of first material at the first side of the intermediate product, the first material being different from the base material so as to result in the intermediate product having pits comprising a layer of said first material, and - subjecting part of the layer of said first material to ion beam milling to provide through-holes in the layer of first material.
Various MEMS devices, such as i) probes comprising a hollow cantilever or ii) sieves, comprise at least one through-hole in a layer of first material such as silicon nitride. The through-hole is for example in a face of a pyramidal tip of the cantilever of a MEMS probe. MEMS probes comprising hollow cantilevers having a tip are used in life sciences for a variety of purposes, two of them being the delivery of a substance to or extraction of material from a cell. In that case, the tip of the MEMS probe will have to penetrate through the cell wall. Material of the cell wall should not clog the opening at the tip of the probe. For this reason, preference is given to probes having the opening (through-hole) in a side wall or pyramidal edge of the tip, instead of at the tip's distal end. In the art, probes with a cantilever comprising a conduit and having a tip are routinely produced. To create the opening of the conduit at the tip, use is made of focussed ion beam etching, wherein a beam of ions is focussed on a wall of a tip to locally etch said wall of first material and form the through-hole.
While MEMS techniques allow MEMS devices such as probes comprising cantilevers having a tip to be manufactured in large numbers simultaneously, this step of creating the opening (a through-hole) at the tip, has to be performed for each tip individually, and consecutively, which is time consuming and costly. Also, there is a risk of damage to the opposite wall of the tip once the focussed ion beam has penetrated the wall of the tip.
The objective of the present invention is to provide a method allowing for the creation of through-holes in a batch process, i.e. simultaneously creating a multitude of through-holes. It is a further object of the present invention to provide a method allowing for the batch-wise production of through-holes in pits comprising a layer of the first material, the through-holes being at a distance from the distal ends of said pits.
To this end, a method according to the preamble is characterized in that the method further comprises - after the step of providing the layer of first material and before the step of ion beam milling - providing a second layer of a second material that is different from the first material on the layer of first material, and - providing the second layer of the second material with a plurality of holes, the holes being provided at the central locations of the pits, and - with the second layer of the second material comprising the plurality of holes at central locations of the pits, subjecting the first side of the base substrate provided with the second layer of the second material to said step of ion beam milling using said second layer of the second material as a shadow mask by having the ion beam at an angle a to the normal to the base main plane of at least 5°.
Thus, the layer of first material is subjected to ion beam milling, as a result of which at the central locations off-center holes are formed in said layer of first material. Subsequent removal of base material at the location of the pits will result in through-holes accessible from both the first side and the second side.
In the present application, the base substrate will in general be a wafer. The wafer is for example a silicon wafer, which may be used to manufacture probes comprising four-sided or three-sided pyramidal pits, as desired, depending on the crystal orientation of the starting wafer with respect to the base main plane. For four-sided and three-sided pyramidal tips these are 100 and 111 silicon respectively.
The method according to the invention is less sensitive to the processing conditions of the step of directional dry etching, because over etching merely results in damage to the base material of the substrate, which for many applications will be removed anyway.
After locally penetrating the layer of first material, the method will be continued using any conventional steps for manufacturing the MEMS device that is desired. By way of example, for a probe comprising a hollow conduit, a sacrificial conduit layer will be provided, followed by further wall material for the conduit covering said sacrificial conduit layer, and etching to remove the sacrificial conduit layer material, so as to result in a hollow conduit. Removing crystalline base material at the location of the pyramidal pit will result in a freely extending cantilever. Such methods are known in the art, for example from WO2012/096571.
According to a favourable embodiment, the method comprises at least one further method step for manufacturing a plurality of MEMS devices, a MEMS device comprising a through-hole in the first layer. A typical MEMS device according to the present invention is a probe, e.g. for taking a sample from a cell, or introducing material into a cell.
According to a favourable embodiment, the method comprises further steps for manufacturing a plurality of probes wherein - each probe of the plurality of probes comprises - a probe base section - having a probe base main plane, and - comprising a first opening of a conduit; and - a cantilever protruding from said probe base section parallel with the probe base main plane, said cantilever having - a proximal end connected to the probe base section, and - a distal cantilever end; said cantilever comprising a tip having a distal tip end, said tip comprising a second opening of said conduit at a location away from the distal tip end; wherein the second opening is formed by at least one step comprising the step of ion beam milling of the first layer of first material. MEMS probes are an important application area and for the state of the art forming the second holes in a face of the tip is a major cost factor because so far they had to be milled individually with accurate aiming of a focussed ion beam. The present invention does not require focussed ion beam milling individual tips. The term "in a face" does not exclude that the hole is in two adjacent faces, i.e. crossing a pyramidal ridge.
According to a favourable embodiment, the base material is a crystalline base material, and before the base substrate is provided with the first layer of first material, the method comprises the step of - etching the base substrate at the first side to form a plurality of pits in said crystalline base material, the pits comprising a face that is at an angle to the main plane.
Pits are typically formed using anisotropic etching of the base material, which allows for the formation of pyramidal pits. Thus MEMS techniques allow for the manufacture of probes having a sharp pyramidal tip. With a probe comprising a sharp tip, excessive damage to the cell is to be avoided. The probe may also serve a dual role, because the tip may be used for scanning using one of a variety of scanning techniques known in the art. A typical crystalline base material used in the art is silicon (1,0,0).
The present invention will now be illustrated with reference to the drawing where
Fig. 1 shows a probe as can be manufactured using the method according to the invention, in top view (top) and cross-sectional view (bottom), both views being vertically aligned;
Fig. 2A to Fig. 2J illustrate a method of manufacturing the probe according to Fig. 1 in top view (top) and cross-sectional view (bottom), both views being vertically aligned;
Fig. 3a shows a Scanning Electron Microscope image of a probe manufactured according to the invention; and
Fig. 3b shows a detail of the probe of Fig. 3A, with inverted gray scale at the right.
Fig. 1 shows a probe 100 as can be manufactured using the method according to the invention, in top view (top) and cross-sectional view (bottom), both views being vertically aligned.
The probe 100 comprises a probe base section 110 and a cantilever 120 extending from the probe base section 110. The cantilever 120 has a proximal end 121 connected to the probe base section 110 and a distal cantilever end 122.
The distal cantilever end 122 comprises a pyramidal tip 130 comprising a pyramidal tip end 131. In a face of the pyramidal tip 130, i.e. away from the pyramidal tip end 131, there is a through-hole 132 manufactured in accordance with the present invention.
The probe 100 comprises an elongated conduit 140 extending from a reservoir 150 at the probe base section 110 through the cantilever 120 to the through-hole 132.
The conduit 140 comprises a first opening 141 and the second opening is defined by the through-hole 132.
The method according to the invention will now be illustrated using Fig. 2A to Fig. 2J, which show in top view and cross-sectional view a method of manufacturing the probe 100 of Fig. 1. The method according to the present invention allows for a multitude of through-holes 132 and hence probes 100 to be manufactured at once, but the figures will show one probe 100 in the making only. A silicon wafer 200 having a thickness of 380 urn is shown (Fig. 2A) in top view. The silicon wafer 200 is of (1,0,0) silicon. If a pyramidal tip with three faces is desired, (1,1,1) silicon may be used instead.
Using a mask, pyramidal pits 210 (only one shown, singulars are used in the remainder of the figure description) is etched by wet anisotropic etching of the silicon using 25% KOH (Fig. 2B). The pyramidal pit 210 is 10 urn by 10 urn. A thin layer of first material 220 (300 nm), here silicon nitride, is deposited (Fig. 2C) on the silicon wafer 200 comprising a pyramidal pit 210 (Fig. 2C) . The silicon nitride will be part of a wall defining the conduit 140 and the pyramidal tip 130. A thin layer of a second material 230 in this case 400 nm thick silicon oxide was formed as a masking material on top of the first layer of first material 220 and provided with a small opening 231 centrally located at the bottom of the pyramidal pit 210 using corner lithography (Fig. 2D).
Other techniques can be used instead, for example deposition of silicon oxide by Low Pressure or Plasma Enhanced Chemical Vapor Deposition (LPCVD or PECVD) followed by optical lithography and silicon oxide etching.
The central location of a pit is the location where the pit is the deepest. Typically the openings 231 are concentric holes.
The wafer 200 provided with the layer of silicon dioxide is etched using an ion beam at an angle by using an ion beam miller (Fig. 2E) using argon as inert gas. The angle a (with respect to the normal to the surface of the original wafer 200) was 25°.
This results in an off-center through-hole 132 in the layer of first material 220 (Fig. 2F) . Because a plurality of probes is manufactured using the present method, a plurality of through-holes 132 is formed at the same time, and not formed consecutively. The position of the through-hole 132 can to some extent be tuned by adjusting the etching angle a.
Now the silicon dioxide layer of second material 230, i.e. the layer that served as a masking material, is removed using hydrofluoric acid (HF) (Fig. 2G) .
The remainder of the probe 100 is manufactured according to well-known practices, by providing the wafer obtained in the previous step with a patterned layer of sacrificial material 240, here polycrystalline silicon with a thickness of 1 um (Fig. 2H). A further layer 250 of silicon nitride having a thickness of 300 nm is deposited, covering the silicon nitride layer of first material 220 and the layer of sacrificial material 240. It is subsequently etched by Reactive Ion Etching to create an etching window 251 so as to expose part of the sacrificial layer of material 240 at a location that will later on be at the probe base section 110.
The further layer of material 250 is bonded to a glass cover 260 by anodic bonding (Fig. 2J). The glass cover 260 has a cover hole 261 (a through-hole) that will allow access of etchant to the polycrystalline sacrificial material at the location of the cover hole 261 and, once the silicon of the wafer has been etched away, at the through-hole 132.
Etching with hot Tetramethylammonium hydroxide (TMAH) solution results in the probe 100, shown in Fig. 1.
Fig. 3A shows a Scanning Electron Microscope image of a probe 100 manufactured according to the invention. The pyramidal tip 130 and cantilever 120 are visible. The through-hole 132 is too small to see.
Fig. 3B shows a zoomed in SEM picture, showing a detail of the probe 100 of Fig. 3A. To avoid reproduction problems, the detail is shown with inverted gray scale tones at the right. The through-hole 132 is visible near the tip end 131 of the pyramidal tip 130.

Claims (4)

1. Werkwijze voor het vervaardigen van een veelheid aan doorgaande gaten (132) in een laag van eerste materiaal (220) waarbij een tussenliggend product wordt onderworpen aan een veelheid aan werkwijze-stappen, waarbij het tussenproduct - een eerste zijde en een tweede zijde definieert, en - een basis-substraat omvat, waarbij het genoemde basis-substraat een basis-materiaal omvat, waarbij aan de eerste zijde het oppervlak van het basis-substraat een hoofdvlak definieert; waarbij de veelheid aan werkwijze-stappen de stappen omvat van - het voorzien van de eerste zijde van het basis-substraat van het tussenproduct van een veelheid aan putjes (210) in het genoemde basis-materiaal, en - het aan het basis-substraat verschaffen van de laag van eerste materiaal (220) aan de eerste zijde van het tussenproduct, waarbij het eerste materiaal anders is dan het basis-materiaal teneinde erin te resulteren dat het tussenproduct putjes (210) heeft die een laag van het genoemde eerste materiaal (220) omvatten, en - het onderwerpen van een deel van de laag van het genoemde eerste materiaal (220) aan ion beam milling voor het verschaffen van doorgaande gaten (132) in de laag van eerste materiaal (220); met het kenmerk, dat de werkwijze verder omvat - na de stap van het verschaffen van de laag van eerste materiaal (220) en voor de stap van ion beam milling - het verschaffen van een tweede laag van een tweede materiaal (230) dat anders is dan het eerste materiaal op de laag van eerste materiaal (220), en - het voorzien van de tweede laag van het tweede materiaal (230) van een veelheid aan gaten, waarbij de gaten zijn verschaft bij de centrale locaties van de putjes (210), en - met de tweede laag van het tweede materiaal (230) dat de veelheid aan gaten bij centrale locaties van de putjes (210) omvat, het onderwerpen van de eerste zijde van het basis-substraat voorzien van de tweede laag van het tweede materiaal (230) aan de genoemde stap van ion beam milling onder gebruikmaking van de genoemde tweede laag van het tweede materiaal (230) als een schaduw-masker door de ionenbundel onder een hoek α ten opzichte van de normaal van het basis-hoofdvlak te hebben van ten minste 5°.A method of manufacturing a plurality of through holes (132) in a layer of first material (220) wherein an intermediate product is subjected to a plurality of process steps, wherein the intermediate defines - a first side and a second side and - comprises a base substrate, said base substrate comprising a base material, the surface of the base substrate defining a major surface on the first side; the plurality of method steps comprising the steps of - providing the first side of the base substrate with the plurality of pits (210) in said base material, and - providing it to the base substrate of the layer of first material (220) on the first side of the intermediate, the first material being different from the base material to result in the intermediate having pits (210) that have a layer of said first material (220) ), and - subjecting a portion of the layer of said first material (220) to ion beam milling to provide through holes (132) in the layer of first material (220); characterized in that the method further comprises - after the step of providing the layer of first material (220) and before the step of ion beam milling - providing a second layer of a second material (230) that is different then the first material on the layer of first material (220), and - providing the second layer of the second material (230) with a plurality of holes, the holes being provided at the central locations of the wells (210) and - with the second layer of the second material (230) comprising the plurality of holes at central locations of the wells (210), subjecting the first side of the base substrate provided with the second layer of the second material (230) to said ion beam milling step using said second layer of the second material (230) as a shadow mask by having the ion beam at an angle α to the normal of the base-main plane of at least 5 °. 2. Werkwijze volgens conclusie 1, waarbij de werkwijze ten minste één verdere werkwijze-stap omvat voor het vervaardigen van een veelheid aan MEMS-inrichtingen, waarbij een MEMS-inrichting een doorgaand gat (132) in de eerste laag (250) omvat.The method of claim 1, wherein the method comprises at least one further method step for manufacturing a plurality of MEMS devices, wherein a MEMS device comprises a through hole (132) in the first layer (250). 3. Werkwijze volgens conclusie 2, waarbij de werkwijze verdere stappen omvat voor het vervaardigen van een veelheid aan probes (100) waarbij - elke probe (100) van de veelheid aan probes (100) omvat - een probe-basissectie (110) - die een probe-basishoofdvlak bezit, en - die een eerste opening (231) van een leiding (140) omvat; en - een cantilever (120) die uitsteekt vanaf de genoemde probe-basissectie (110) parallel aan het probe-basishoofdvlak, waarbij de genoemde cantilever (120) - een met de probe-basissectie (110) verbonden proximaal eind (121), en - een distaai cantilever-eind (122) bezit; waarbij de genoemde cantilever (120) een tip omvat die een distaai tip-eind (131) bezit, waarbij de genoemde tip een tweede opening (231) omvat van de genoemde leiding (140) op een plaats die bij het distale tip-eind (131) vandaan ligt; waarbij de tweede opening (231) door ten minste één stap wordt gevormd welke de stap omvat van ion beam milling van de eerste laag (220) van eerste materiaal.The method of claim 2, wherein the method comprises further steps of manufacturing a plurality of probes (100) wherein - each probe (100) comprises the plurality of probes (100) - a probe base section (110) - which has a probe base major face, and - which includes a first opening (231) of a conduit (140); and - a cantilever (120) protruding from said probe base section (110) parallel to the probe base face, said cantilever (120) - a proximal end (121) connected to the probe base section (110), and - has a distal cantilever end (122); said cantilever (120) comprising a tip having a distal tip end (131), said tip including a second opening (231) of said conduit (140) at a location at the distal tip end ( 131) is from; wherein the second opening (231) is formed by at least one step which comprises the step of ion beam milling of the first layer (220) of first material. 4. Werkwijze volgens een der voorgaande conclusies, waarbij het basis-materiaal een kristallijn basis-materiaal is, en alvorens het basis-substraat wordt voorzien van de eerste laag van eerste materiaal (220), de werkwijze de stap omvat van - het aan de eerste zijde etsen van het basis-substraat voor het vormen van een veelheid aan putjes (210) in het genoemde kristallijne basis-materiaal, waarbij de putjes (210) een zijde omvatten die een hoek maakt met het hoofdvlak.A method according to any one of the preceding claims, wherein the base material is a crystalline base material, and before the base substrate is provided with the first layer of first material (220), the method comprises the step of first side etching of the base substrate to form a plurality of wells (210) in said crystalline base material, the wells (210) comprising a side that makes an angle with the main surface.
NL2016329A 2016-02-25 2016-02-25 A method of manufacturing a plurality of through-holes in a layer of first material. NL2016329B1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL2016329A NL2016329B1 (en) 2016-02-25 2016-02-25 A method of manufacturing a plurality of through-holes in a layer of first material.
US15/444,010 US10207244B2 (en) 2016-02-25 2017-02-27 Method of manufacturing a plurality of through-holes in a layer of first material
EP17158208.3A EP3210936B1 (en) 2016-02-25 2017-02-27 A method of manufacturing a plurality of through-holes in a layer
US15/444,086 US9975761B2 (en) 2016-02-25 2017-02-27 Method of manufacturing a plurality of through-holes in a layer of first material
EP17158214.1A EP3210937B1 (en) 2016-02-25 2017-02-27 A method of manufacturing a plurality of through-holes in a layer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2016329A NL2016329B1 (en) 2016-02-25 2016-02-25 A method of manufacturing a plurality of through-holes in a layer of first material.

Publications (1)

Publication Number Publication Date
NL2016329B1 true NL2016329B1 (en) 2017-09-11

Family

ID=59923136

Family Applications (1)

Application Number Title Priority Date Filing Date
NL2016329A NL2016329B1 (en) 2016-02-25 2016-02-25 A method of manufacturing a plurality of through-holes in a layer of first material.

Country Status (1)

Country Link
NL (1) NL2016329B1 (en)

Similar Documents

Publication Publication Date Title
US20180194011A1 (en) Targets and processes for fabricating same
US10207244B2 (en) Method of manufacturing a plurality of through-holes in a layer of first material
US8828243B2 (en) Scanning probe having integrated silicon tip with cantilever
CA2433738A1 (en) Method for microfabricating structures using silicon-on-insulator material
US6930366B2 (en) Method for forming a cavity structure on SOI substrate and cavity structure formed on SOI substrate
NL2016329B1 (en) A method of manufacturing a plurality of through-holes in a layer of first material.
EP3210935B1 (en) A method of manufacturing a plurality of through-holes in a layer of material
NL2016328B1 (en) A method of manufacturing a plurality of through-holes in a layer of first material.
JP4460501B2 (en) Micro sample table
NL2026676B1 (en) A method of manufacturing a micro-fluidic probe
JP4714889B2 (en) Silicon prism and manufacturing method thereof
CN112158794A (en) Method for preparing atomic force microscope probe stepped substrate by adopting plasma etching
US20140322918A1 (en) Micro-posts having improved uniformity and a method of manufacture thereof
US20060037932A1 (en) Method and micromechanical component
NL2026730B1 (en) A method of manufacturing a MEMS device
US20220187336A1 (en) A method of providing a mems device comprising a pyramidal protrusion, and a mold
US20100224590A1 (en) Method for producing microneedle structures employing one-sided processing
RU2698486C1 (en) Method for manufacturing of integral converters
KR101337568B1 (en) Method for manufacturing a micro-grid structure
EP1361192A2 (en) Methods of metal coating contact holes in mems and similar applications
EP2688091A1 (en) Method for producing a cavity by anisotropically removing material from a substrate

Legal Events

Date Code Title Description
MM Lapsed because of non-payment of the annual fee

Effective date: 20190301