Abstract
This invention is about a product of a flip chip thin film hybrid screen printed electrode. It combines a primary screen printed electrode (SPE) device and a thin film material coated chip, in order to make a hybridized product. The product is used as a test strip for electrochemical analysis, such as environmental, bio-electrochemical and biomedical sensors. The hybridized electrodes design takes the benefits of low cost of screen printing technology, and high sensitivity of thin film coating nanotechnology. This invention is also about applying a flip chip method to manufacture the hybrid electrode. A chip of thin film material coated solid state substrate is surface mounted to a preliminary perforated SPE by a flip chip method/process. This method/process is fast, easy, cheap, uniform, and suitable for large scale manufacturing.
Claims
1. A test strip for electrochemical stripping analysis, comprising: a main body made of a insulative sheet material in a strip format, having a perforated hole, having a upside surface and down side surface; a set of counter electrode, on the up side surface of the main body , in the proximity of the hole; a set of reference electrode, on the up side surface of the main body, in the proximity of the hole; a set of work electrode, made of a chip, mounted to the down side surface of the main body;
2. For the test strip product of the claim 1, the work electrode chip is made of a solid state substrate, such as a piece of graphite paper, carbon paper, ceramics, mica, glass, polymer plastics, silicon wafer, and a thin film material is deposited on the chip surface;
3. For the test strip product of the claim 1, the chip is coated by a thin film technology via a physical vapor deposition (PVD), a chemical vapor deposition (CVD), or a plasma enhanced chemical vapor deposition (CVD) method;
4. For the test strip product in the claim 1, the thin film material is made of the vertically free standing graphene containing carbon nanosheets material (Vertical Graphene).
5. For the test strip product of the claim 1, the sheet thickness of the test strip main body is in the range of 100 micrometers to 3 millimeters.
6. For the test strip product of the claim 1, the perforated hole is in circular shape.
7. For the test strip product of the claim 1, wherein: between the surface mounted chip and the test strip's down side surface, there is a layer of conductive or non-conductive glue material, in order to bonding the chip and down side surface.
8. For the test strip product of the claim 1, wherein: the main body has a multiplicity of holes and comprise a multiplicity of reference electrodes and counter electrodes, and a multiplicity of work electrode chips mounted to each perforated holes respectively.
9. A method of making the test strip product in claim 1, includes but not limited to the processes of: Step 1. To make a preliminary test strip main body, whose up and down side surface are both screen printed with traces of electrodes; Step 2. To perforate the main body with a through hole; Step 3. To apply a thin layer of a glue material on the down side surface. Step 4. To surface mounting a chip to the down side surface before the glue drying or curing. The chip was preliminary deposited by a thin film material. The chip completely covers up and seals the perforated hole from the down side. Step 5. To drying or curing the glue material till solidification in order to seal the perforated hole from the down side. Step 6. To attach a protection backplate on the chip mounted down side.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view showing the front, the left side, and the top of the flip chip thin film hybrid screen printed electrode test strip;
[0013] FIG. 2 includes an exploded view, a top view, a bottom view, and a schematic cross section view at the axis of symmetry, thereof;
[0014] FIG. 3 is a perspective view of a chip of a thin film material coated solid state substrate, and microscopic view of the thin film coating material: vertically free standing graphene containing carbon nanosheets;
[0015] FIG. 4 is a top view of a set of variants of the flip chip thin film hybrid screen printed electrode test strips;
[0016] FIG. 5 is a top view of a second set of variants of the flip chip thin film hybrid screen printed electrode test strips;
[0017] FIG. 6 is a top view of a third set of variants of the flip chip thin film hybrid screen printed electrode test strips.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to the invention in more details, in FIG. 1, it shows a flip chip thin film hybrid screen printed electrode test strip (FCTFSPETS), where 100 is a main body or a substrate of the FCTFSPETS, 110 is a chip of a thin film material coated solid state substrate, 120 and 130 are a reference electrode and a counter electrode, 140 and 150 are electrode leads for the counter electrode and reference electrode respectively. 100 is usually made by polyethylene terephthalate (PET). 120, 130, 140 and 150 are printed on 100 by screen printing technology with various formulas and function, e.g. carbon paste containing a mixture of carbon ink and resin material being used for counter electrode, and silver paste being used for the electrode leads. Beside above mentioned, sometimes there are extra layers printed on the main body, e.g. insulating layers, protecting layers, logos, and texts. The thin film material 110 coated on the solid state substrate is exposed to the open space as a functioning work electrode material. An obvious benefit of this configuration is the thin film electrode material is geometrically recessed below the perforated hole structure, thus the thin film electrode materials can be protected against surface abrasion damage during manufacturing and logistic transportation.
[0019] The exploded view of FIG. 2 shows how the thin film electrode material is attached to the down side surface of the primary SPE main body. A thin film material is by definition having thickness of 1 micron or less, which must coat (or called grow up in a strict Materials Science description) on a solid state substrate to work. 210 is a chip of solid state substrate with thin film electrode material growing on the up side surface. Flip chip technology means the up side of the chip, which has the thin film electrode material, is attached to the down side surface of a primary SPE main body via a glue material, while the thin film electrode material is exposed to open space, through the perforated hole of the SPE main body. In other words, between the surface mounted chip and the through-holed SPE down side surface, there is a layer of conductive or non-conductive glue material, in order to bonding the chip and primary SPE main body. Importantly, when choosing and applying the glue material, it has to be thin, no pollution and no disturbance to future electrochemical analysis work. The glue material must not cover the thin film coating exposed to open space.
[0020] The top view of FIG. 2 shows an actual functioning surface of the FCTFSPETS. In the bottom view of FIG. 2, 220 is a protecting layer for the solid state substrate (or the chip), and 230 is a lead of the working electrode made by thin film electrode material.
[0021] The schematic cross section view at the axis of symmetry of FIG. 2 further explains the flip chip technology, where 240 is the SPE main body, 250 is the counter electrode printed on SPE main body via screen printing technology, 280 is a conductive layer printed on SPE main body via screen printing technology, 260 is the glue material to attach the up side surface of a chip of solid state substrate with thin film electrode material to the down side surface of a primary SPE main body, 220 is the protecting layer, and 270 is the thin film electrode material exposed to open space.
[0022] FIG. 3 gives an microscopic view of the solid state substrate 320 with thin film electrode material 310. 311 and 312 are scanning electron microscope (SEM) photos of vertical graphene and planer graphene as exemplary thin film electrode materials.
[0023] FIG. 4 gives a set of examples of variants of the invented flip chip thin film hybrid screen printed electrode test strips (FCTFSPETS) in a top view. 410 is a FCTFSPETS with an integrated reference electrode and an integrated counter electrode. 420 is a FCTFSPETS which is integrated with a row of FTSPETS unit. 430 is a FCTFSPETS only containing a single electrode.
[0024] FIG. 5 gives a second set of examples of variants of the invented FTSPETS in a top view. The exposed functioning thin film electrode material can be round 510, located at the edge of the main body 520, rectangular 530, as an array of sub units 540, or other configurations.
[0025] FIG. 6 gives a third set of examples of variants of the invented FTSPETS in an exploded view. At the chip's down side surface (no thin film coatings), there is a backplate to protect the FTSPETS. The backplate can be made by a variety of materials, e.g. a transparent material 610 often to be used in electrochemiluminescence, and an electrical conductive material 620 to enhance the conduction of FTSPETS.
