Pyrex wafer

Microfabrication involves multiple photolithographic and etch steps, a silicon fusion bond and an anodic bond (see especially [12] for a detailed description, but also [11]). A time-multiplexed inductively coupled plasma etch process was used for making the micro channels. The microstructured plate is covered with a Pyrex wafer by anodic bonding. 

Later, Pattekar and Kothare [21] presented a silicon reactor fabricated by deep reactive ion etching (DRIE). It carried seven parallel micro channels of 400 pm depth and 1 000 pm width filled with commercial Cu/ZnO catalyst particles (from Siid-Chemie) trapped by a 20 pm filter, which also was made by DRIE, in the reactor. The reactor was covered by a Pyrex wafer applying anodic bonding. Details of the reactor are shown in Figure 2.3. 

By placing vacuum at the exit of the reactor the catalyst particle could be unloaded, and using the inert gas stream at the inlet of the reactor, new catalyst can be placed. At the outlet of the reaction channel two posts 25 pm apart act as a filter to retain the catalyst particles. In addition, some channels were used to hold thermocouples or optical fibers to monitor the experimental conditions. To prevent corrosion of silicon by gaseous chlorine, the channels are covered with a silicon oxide layer of about 5 nm thickness. The reactor is capped with a Pyrex wafer [39]. A more detailed description of the reactor is given in [61]. 

Anodic bonding of Si to Pyrex was commonly used to create a sealed Si chip [1,281,442,820,836]. Various bonding conditions used are summarized in Table 2.2. A positive voltage is applied on the Si wafer with respect to that of the Pyrex wafer (negative) [91,92,281]. 

Fig. 5.19. One step for the integration of an optical biosensor into a-lab-on-a-chip a Si wafer containing the devices is bonding with a Pyrex wafer, which has been previously processed with SU-8 polymer to define the microfluidics.

Y.-S. Liao, W.-Y. Peng Study of hole-machining on Pyrex wafer by electrochemical discharge machining (ECDM). Materials Science Forum 505—507 (2006), p. 1207. 

The mass spectrometer is assembled from four wafers, three silicon and one glass wafer, hermetically sealed by anodic bonding The geometries of the orifice and the plasma electrodes are fabricated via anisotropic etching of Si by KOH The plasma chamber for this first approach was drilled into the Pyrex wafer For the electrodes of the mass separator a deep anisotropic plasma etching process is used by which perpendicular trenches more than 200 im deep with micrometer tolerances can be generated The electrodes are metallized for a defined potential within the separator... 

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