Epoxy mold making and micromilling for microfluidics

Patent metadata

Field	Value
Publication number	US-10682789-B2
Application number	US-201515503360-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Aug 29, 2014
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A method for efficiently manufacturing and fabricating microfluidic chips, where a base mold is formed to have positive-relief features used to cast an intermediary template chip with negative-relief features having dimensions of a scale in the micron range. The intermediary template chip is used to case a production mold, which is formed of a reinforced epoxy resin that, once hardened into a solid epoxy member, can withstand the structural pressures of a CNC machining system. The production mold can be refined by a CNC machining, where the refined production mold is then used to cast production chips to be used as microfluidic chips.

First claim

What is claimed is:

1. A method for forming microfluidic chips comprising:
forming a base mold;
casting an intermediary template chip mold based on the base mold;
casting a production mold based on the intermediary template chip mold, wherein the production mold comprises epoxy;
refining the production mold to generate a refined production mold, wherein refining the production mold comprises changing the shape of the production mold;
casting a production chip based on the refined production mold; and
modifying the production chip with a hot embossing process.

2. The method according to claim 1 , wherein the base mold comprises a silicon wafer and a photoresist material.

3. The method according to claim 2 , wherein forming the base mold further comprises rotating the silicon wafer as the photoresist material is deposited onto the silicon wafer, such that the photoresist material forms a film on the silicon wafer.

4. The method according to claim 3 , wherein forming the base mold further comprises exposing the rotating silicon wafer and the photoresist material to UV light.

5. The method according to claim 4 , wherein the rotating silicon wafer and the photoresist material are exposed to UV light incident at an angle from about 30° to about 35° from normal.

6. The method according to claim 1 , wherein forming the base mold further comprises forming positive-relief features on the base mold.

7. The method according to claim 6 , wherein forming the base mold further comprises forming positive-relief features on the base mold having draft angles of about 15°.

8. The method according to claim 1 , wherein the intermediary template chip mold comprises PDMS.

9. The method according to claim 1 , wherein the intermediary template chip mold has a plurality of microchannels, where the plurality of microchannels have dimensions of less than about one hundred microns (100 μm).

10. The method according to claim 1 , wherein the production mold comprises an aluminum-filled epoxy.

11. The method according to claim 10 , wherein refining the production mold comprised of aluminum-filled epoxy further comprises micromilling positive-relief features of the production mold.

12. The method according to claim 11 , wherein micromilling positive-relief features of the production mold further comprises altering a height of the positive-relief features to have a variable height.

13. The method according to claim 11 , wherein the micromilling of positive-relief features of the production mold is controllable by a CNC machining system.

14. The method according to claim 1 , wherein the production chip is comprises PMMA.

15. The method according to claim 1 , wherein the production chip has a plurality of microchannels, where the plurality of microchannels have dimensions of less than about one hundred microns (100 μm).

16. The method according to claim 1 , wherein the hot embossing process comprises applying force on the production chip with a metal press.

17. The method according to claim 16 , wherein the metal press is operated at a peak heat level of about 140° C. to about 180° C.

18. The method according to claim 16 , wherein the metal press is operated at a peak pressure level of about 3000 lbf.

19. The method according to claim 16 , wherein the hot embossing process forms one or more through-holes in the production chip.

20. The method according to claim 16 , wherein the hot embossing process forms one or more indentations in the production chip.

Assignees

• Bio Rad Laboratories

Inventors

• Konstantinou Daniel
• Wan Alwin
• Rosenzweig Tal
• Sadri Amir
• Kircanski Nenad
• Young Edmond

Classifications

• B29K2883/00

  Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as mould material · CPC title

• B01L3/502707

  characterised by the manufacture of the container or its components · CPC title

• B29C39/003

  characterised by the choice of material · CPC title

• B29C33/3878 Primary

  used as masters for making successive impressions · CPC title

• B29K2033/12

  Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate · CPC title