Bonding Panel-Shaped Bodies with Spacers to Control Adhesive Shrinkage
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Solution Overview
Problem
Adhesive shrinkage during bonding of lightweight composite bodies used in positioning tables for microlithography leads to deformations and bending, which can render the stages unusable due to alignment errors, and thickening the walls to mitigate this increases mass and inertia, contrary to the intended reduction.
Innovation Solution
The method involves creating spacers on the bonding surfaces and applying adhesive between them, with a controlled distance from the adhesive periphery to minimize deformation, particularly by positioning the last spacer at a distance between 20 μm and 250 μm to prevent bending, using spacers with varying stiffness and materials like glass beads, and selecting adhesives with suitable viscosity and shrinkage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If adhesive bonding is used to join lightweight composite bodies, then mass reduction is achieved, but adhesive shrinkage causes deformations and bending
Solution Approach 1:
The patent applies preliminary action by positioning spacers on the bonding surface before adhesive application. These spacers pre-establish the correct spacing and alignment between bonding surfaces, compensating for the anticipated adhesive shrinkage. The spacers are positioned at specific distances from the bonding surface edge to ensure that even after adhesive contraction, the final alignment precision is maintained.
Solution Approach 2:
The spacers act as intermediary elements between the bonding surfaces. They mediate the bonding process by providing physical separation and alignment reference points that prevent direct contact between the bonding surfaces in critical areas. This intermediary structure allows the adhesive to bond the components while maintaining precise alignment despite shrinkage forces.
2Stability of the object's composition
If wall thickness is increased to prevent deformation from adhesive shrinkage, then structural stability is improved, but mass increases
Solution Approach 1:
The spacers are positioned in advance to pre-compensate for adhesive shrinkage effects. By calculating and setting the optimal distance between spacers and bonding surface edge, the design anticipates the shrinkage amount and positions spacers accordingly. This preliminary positioning ensures that after adhesive contraction, the bonding surfaces remain properly aligned without requiring increased wall thickness.
Solution Approach 2:
The patent applies local quality by using spacers only in specific critical areas where alignment precision is most important, rather than uniformly thickening all walls. The spacers provide localized structural support and alignment control at the bonding interface, allowing thin-walled lightweight construction in non-critical areas while maintaining stability where needed.
3Manufacturing precision
If spacers are positioned close to the bonding surface edge, then alignment precision is maintained, but adhesive coverage is reduced
Solution Approach 1:
The patent optimizes the distance parameter between spacers and bonding surface edge to achieve the best compromise between alignment precision and adhesive coverage. Through calculation and experimentation, specific distance ranges are determined that ensure spacers are close enough to maintain precision but not so close as to severely limit adhesive application area. This parameter optimization allows both requirements to be satisfied simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces or minimizes deformations and bending of panel-shaped bodies, ensuring accurate alignment and maintaining the lightweight structure of the positioning tables by optimizing the distance between spacers and adhesive periphery, thus maintaining the tables' usability in microlithography applications.
Implementation Method 1
the adhesive that is used cures or, when the composite body is introduced into an appropriate environment (for example a nitrogen or vacuum environment), it dries out, as a result of which the adhesive undergoes shrinkage
Data Source
AI summary
A method for bonding a first body (2) to a second, panel-shaped body (3) at bonding surfaces (2a, 3a) lying opposite each other, the second body (3) projecting in at least one direction (X) beyond an edge (2′) of the first body (2). The method includes: producing a plurality of spacers (4a to 4e, 4a′ to 4e′) on at least one of the bonding surfaces (2a), applying adhesive (5) into intermediate spaces (6a to 6d) between the spacers beyond an outer spacer (4e, 4e′) as far as an adhesive periphery (5a), which is formed at an edge (2′) of the first body (2), and bonding the bodies (2, 3) by bringing the bonding surfaces (2a, 3a) into contact at the spacers (4a′ to 4e′). A prescribed distance (d) between the adhesive periphery (5a) and the outermost spacer (4e) is set to provide a desired state of deformation of the panel-shaped body (3) after a shrinkage of the applied adhesive (5) (e.g. minimized bending of the body.) In an associated composite body (1), the prescribed distance (d) lies between 20 μm and 250 μm, preferably between 30 μm and 200 μm, in particular between 40 μm and 150 μm.