Attachment method for microfluidic device

Inventors

Lord, Peter C.

Assignees

Physiologic Devices Inc

Abstract

In embodiments, a silicon part and a titanium part may be soldered together without breakage or instability. In embodiments, silicon and titanium may be soldered together with a soft solder joint including indium silver, where the temperature excursion between solder solidus and use temperature limits the strain between the two surfaces. In embodiments a silicon micropump surface may be treated to remove its silicon oxide coating, and then Ti—W, Nickel, and gold layers successively sputtered onto it. A corresponding titanium manifold may be ground flat, and plated with electroless nickel. The nickel plated manifold may then be baked, so as to create a transition from pure Ti to Ni—Ti alloy to pure Ni at the surface of the manifold, and for protection of the upper Ni surface, a layer of gold may be added. The two surfaces may then be soldered in forming gas.

Core Innovation

The invention relates to a microfluidic device that includes a silicon device having a first solderable surface and a titanium component having a second solderable surface. The silicon device and the titanium component are attached by a solder joint comprising a homogenous single composition solder with a pre-defined thickness configured to accommodate strain due to co-efficient of thermal expansion (CTE) mismatch without breaking apart.

The device further includes one or more rubber seals provided between the silicon device and the titanium component in an area where the solder joint is not provided. At least two springs are attached to the silicon device and to the titanium component, where the springs are configured to reduce tension on the solder joint. The solder joint structure and adjacent sealing and mechanical features are arranged to manage CTE-mismatch strain while maintaining connection integrity.

Claims Coverage

The independent claims are clm-00001 and clm-00017, both covering a microfluidic device that uses a homogenous single composition solder joint of pre-defined thickness to accommodate strain due to CTE mismatch. Across the independent claims, the inventive aspects focus on the solder joint definition and, in clm-00001, additional sealing and mechanical tension-reduction elements.

Across the independent claims, the core coverage is a microfluidic device in which a homogenous single composition solder joint is defined by pre-defined thickness (≥ 25 μm) to accommodate CTE-mismatch strain without breaking apart, together with specified melting point or solidus point limits. Claim clm-00001 further adds rubber seals located where the solder joint is not provided and at least two springs configured to reduce tension on the solder joint.

Stated Advantages

Documented Applications

No documented applications found