Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-02-14
2001-12-04
Osele, Mark A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C137S015010, C137S605000, C137S884000
Reexamination Certificate
active
06325886
ABSTRACT:
BRIEF DESCRIPTION OF THE INVENTION
This invention relates generally to micromechanical devices used to control fluids. More particularly, this invention relates to a technique for establishing a clean, corrosion resistant, and hermetic connection between a micromechanical device and a fluid manifold substrate.
BACKGROUND OF THE INVENTION
Micromechanical devices (also called microelectromechanical (MEM) devices, micromachined devices, and nanostructures) are micron scale, three-dimensional objects constructed using semiconductor processing techniques. As used herein, the term micromechanical refers to any three-dimensional object that is at least partially constructed in reliance upon semiconductor processing techniques.
Micromechanical devices are utilized as fluid control devices. As used herein, the term fluid refers to either a gas or a liquid. Precise fluid control is important in many applications ranging from drug delivery to semiconductor processing equipment.
Micromechanical devices are used to form a variety of fluid flow control devices, including shut-off valves, pressure sensors, mass flow controllers, filters, purifiers, pressure gauges, and the like.
FIG. 1
is a side cross-sectional view of a prior art device including a manifold
20
with an input port
22
and an output port
24
. Mounted on the manifold
20
is a first micromechanical fluid control device
30
in the form of a normally open proportional valve and a second micromechanical fluid control device
32
in the form of a pressure sensor. Reference herein to a micromechanical fluid control device contemplates any device that is exposed to a fluid and operates to sense or control the fluid.
The first micromechanical fluid control device
30
includes a membrane
34
and a membrane control chamber
36
. Fluid in the membrane control chamber
36
is selectively heated, thereby expanding the volume of the membrane control chamber
36
, causing the membrane
34
to deflect and thereby obstruct fluid flow from the input port
22
. By controlling the deflection of the membrane
34
in this manner, a proportional valve operation is achieved.
The second micromechanical fluid control device
32
also includes a membrane
38
. The deflection of the membrane
38
is used to measure the pressure of the controlled fluid. Thus, the second micromechanical fluid control component
32
operates as a pressure sensor.
Each micromechanical fluid control component (
30
,
32
) is mounted on the manifold
20
using a soft, compliant material
40
, such as silicone or epoxy. Ideally, no stresses from the manifold
20
are transmitted to the fluid control components. Isolation of stresses is particularly important in the case of a pressure sensor (e.g. piezoresistive, capacitive, or strain pressure sensors). Pressure sensors are sensitive to the strain of the supporting structure (e.g., a manifold). In particular, if this strain changes over time, the signal produced by the sensor for a given pressure will change, thus decreasing the utility of the sensor.
Although soft, compliant materials have been used with some success, these materials are inappropriate for a large class of applications. In particular, these materials are inappropriate for use in the control and distribution of gases for semiconductor processing. In this context, the gases may be corrosive or toxic. The adhesive
40
between the manifold
20
and fluid control component
30
,
32
must withstand this corrosive and/or toxic substance so that there is no observable change in the functionality of the adhesive
40
.
Furthermore, semiconductor processing equipment also requires a high level of cleanliness. The fluid control components and their attachment material must not measurably alter the character of the controlled fluid. This limitation eliminates many soft, compliant materials from consideration as candidates for component attachment.
Ideally the adhesive is hermetic. However, hermetic seals are typically quite hard, and therefore transfer package stress directly to the micromechanical fluid control component. The adhesive should also be stable, such that signal drift does not develop over time.
In view of the foregoing, it would be highly desirable to provide an improved technique for mounting fluid control components. Ideally, such a technique would provide a stable, hermetic, clean, and corrosion resistant interface between a fluid control component and a manifold.
SUMMARY OF THE INVENTION
The method of the invention includes the step of forming a first ring of a first adhesive around an aperture defined between a micromechanical fluid control device and a substrate. The first adhesive forms a first interface between the micromechanical fluid control device and the substrate that is clean and corrosion resistant. A second ring of a second adhesive is applied around the first ring. The second adhesive forms a second interface between the micromechanical fluid control device and the substrate that is hermetic.
The apparatus of the invention is a micromechanical fluid control system with a first adhesive ring formed around an aperture defined between a micromechanical fluid control device and a substrate. The first adhesive ring forms a first interface between the micromechanical fluid control device and the substrate that is clean and corrosion resistant. A second adhesive ring is formed around the first adhesive ring. The second adhesive ring forms a second interface between the micromechanical fluid control device and the substrate that is hermetic.
The invention provides a stable, hermetic, clean, and corrosion resistant interface between a fluid control component and a manifold.
REFERENCES:
patent: 4051286 (1977-09-01), Abbott
patent: 4793886 (1988-12-01), Okamura et al.
patent: 5084119 (1992-01-01), Barksdale
patent: 5568713 (1996-10-01), Gagne et al.
patent: 5964239 (1999-10-01), Loux et al.
patent: 6048433 (2000-04-01), Maesaka et al.
patent: 6123107 (2000-09-01), Selser et al.
Harris James M.
Selser Michael J.
Weber Walter A.
Osele Mark A.
Pennie & Edmonds LLP
Redwood Microsystems, Inc.
LandOfFree
Method for attaching a micromechanical device to a manifold,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for attaching a micromechanical device to a manifold,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for attaching a micromechanical device to a manifold,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2591789