Structure for capturing express transient liquid phase during diffusion bonding of planar devices

• US 5,935,430 A
• Filed: 07/29/1998
• Issued: 08/10/1999
• Est. Priority Date: 04/30/1997
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Craig, Stephen R.
• Primary Examiner(s): Therkorn, Ernest G.
• Application Number:
  US09/124,107
• Time in Patent Office: 377 Days
• Field of Search: 210/635, 210/656, 210/659, 210/198.2, 204/601, 204/602, 204/603, 204/604, 204/605, 204/451, 204/452, 204/453, 204/454, 422/68.1, 422/69, 422/70, 73/61.52, 73/61.53
• US Class Current: 210/198.2
• CPC Class Codes: B01L 2200/0689 Sealing
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0883 Serpentine channels
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B01L 3/502753 characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation separation in general B01D; microapparatus for analysis using electrophoresis G01N27/44791; sample preparation G01N1/28
• CPC Class Codes: B23K 20/02 by means of a press ; Diffusion bonding B23K20/001, B23K20/04 take precedence
• CPC Class Codes: B23K 33/00 Specially-profiled edge portions of workpieces for making soldering or welding connections; Filling the seams formed thereby B23K11/14 takes precedence
• CPC Class Codes: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81B 2203/0338 Channels
• CPC Class Codes: B81C 2203/032 Gluing
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: G01N 30/6095 Micromachined or nanomachined, e.g. micro- or nanosize

Abstract

A miniaturized planar device formed of first and second planar substrates that may be superimposed and diffusion bonded to form a single, planar integrated assembly. Each of the first and second planar substrates include respective component sections having respective first and second interior surfaces. One or more surface features in at least one of the first and second interior surfaces are thereby enclosed during assembly so as to form at least one corresponding internal fluid-handling feature, such as a conduit having a rectilinear, semicircular, or circular cross section. The perimeter of a surface feature is generally defined by a perimeter land which separates the surface feature from an adjacent moat. The superimposition of the first and second component sections establishes an interface between the abutted portions of the first and second interior surfaces; this interface is then subject to diffusion bonding. Diffusion bonding causes a transient liquid phase to be interposed in the interface; a flow of the transient liquid phase can correct the irregularities, asperities, or other undesired structural aspects in the abutted surfaces. Excess flow of the transient liquid phase tends to flow into the moat, wherein the excess flow may be contained, so as to thereby minimize or prevent undesirable flow of the transient liquid phase into an internal fluid-handling feature.

Claims

1. An integrated assembly, comprising:

first and second planar substrates, each of the first and second planar substrates having respective component sections and having respective first and second interior surfaces, each of the first and second interior surfaces having a respective surface layer;

a first surface feature in at least one of the first and second interior surfaces, the perimeter of the first surface feature being generally defined by a first perimeter land;

an adjacent moat separated from the surface feature by the perimeter land;

the second planar substrate being aligned and superimposed onto the first interior surface in a controlled manner such that the first surface feature is covered by the second interior surface to form an internal fluid-handling feature, and wherein the abutted portions of the surface layers of the first and second substrates being subject to diffusion bonding; and

wherein an excess flow of transient liquid phase is contained in the first moat, so as to thereby minimize excess flow of the transient liquid phase into the internal fluid-handling feature.

2. The integrated assembly of claim 1, further comprising a second surface feature in the alternative one of the first and second interior surfaces, the perimeter of the second surface feature being generally defined by a second perimeter land, and wherein the first and second perimeter lands are joined and diffusion bonded to form the internal fluid-handling feature.

3. The integrated assembly of claim 2, wherein the first and second surface features further comprise complementary microstructures.

4. The integrated assembly of claim 2, wherein the internal fluid-handling feature is a conduit.

5. The integrated assembly of claim 2, wherein the conduit further comprises a surface treatment, whereby the conduit functions as a separation column.

6. The integrated assembly of claim 2, wherein the first and second planar substrates further comprise a metal alloy substrate material prepared for diffusion bonding by electroplating a nickel-base surface layer on the portions of the component sections that are to be subject to diffusion bonding.

7. The integrated assembly of claim 1, wherein the surface feature further comprises a semi-circular channel.

8. The integrated assembly of claim 1, wherein the surface feature further comprises a rectilinear channel.

9. The integrated assembly of claim 1, wherein the adjacent component sections are separated by a linear fold means and the planar substrate is composed of a ductile material in the immediate vicinity of the linear fold means, and is generally inextensible in the component sections, such that the two adjacent component sections may be superimposed by folding the component sections upon each other about the fold axis.