Bonding pads

The last technique commonly employed to deposit metals for compound semiconductors is electroplating (150). This technique is usually used where very thick metal layers are desired for very low resistance interconnects or for thick wire bond pads. Another common use of this technique is in the formation of air-bridged interconnects (150), which are popular for high speed electronic and optoelectronic circuits. 

Inlet and outlet holes matched the fluidic connections of the experimental rig. Electrical connections to bond pads of the heaters and sensors were made using a probe card (Figure 3.17). 

For thermal characterization and temperature sensor calibration a microhotplate was fabricated, which is identical to that on the monoHthic sensor chips, but does not include any electronics. The functional elements of this microhotplate are connected to bonding pads and not wired up to any circuitry, so that the direct access to the hotplate components without electronics interference is ensured. The assessment of characteristic microhotplate properties, such as the thermal resistance of the microhotplate and its thermal time constant, were carried out with these discrete microhotplates. 

Two identical polysilicon temperature sensors with a nominal resistance value of 10 kQ are located in the membrane center. One resistor is connected to the temperature controller, the other sensor is totally decoupled from the circuitry. This second temperature sensor can be directly accessed via bond pads in a four-point configuration. It enables an accurate calibration and a verification of the temperature controller... 

The packaging strategy presented in Sect. 5.1.6 can be directly applied to this array chip (see Fig. 6.15). The number of necessary bond pads is only five, since this chip takes full advantage of the CMOS-MEMS approach. The number of bondpads... 

Additional delay may be imposed by the capacitive loading of branch lines, receivers, and bonding pads attached to the interconnection or by the series inductance of vias or wire bonds. If the additional capacitance can be assumed to be uniformly distributed over the interconnection with electrically short spacing (an assumption that is not always valid), the modified propagation delay (Tpd ) is given by (37)... 

The most advanced implementation of cofired-ceramic-packaging technology is the thermal conduction module (TCM) used in large-scale computers (IBM) (4, 72, 74). This package can accommodate over 100 flip-chip-bonded ICs on a 90 by 90 mm cofired ceramic substrate. The multilayer ceramic substrate contains 33 metal layers for chip pad redistribution, signal interconnection, and power distribution (Figure 14). Each chip contains 120 bonding pads, and 1800 pins are brazed to the bottom of the substrate for connection to a PWB. 

Fig. 6. Photomicrograph illustrating the assembling of the thin film sensor array with the printed circuit board, a. sensor array, b. counter electrode, c. pacer, d. channel for conductive adhesive with conducting pad of PCB, e. inlet hole for conductive adhesive,/ outlet hole for conductive adhesive, g. bonding pads...

In a first embodiment in which windows 28 are etched through the second gate oxide layer 19, column bonding pads 30, shown in solid line, are derived from the second metal layer 20 and contact is made to the columns 21 via extensions from the solid portion of the bonding pad 30 through the windows 28 to the columns 21. 

In a second embodiment in which the column bonding pads 30 are derived from the first metal layer 18, the bonding pads 30 correspond to the lower portion, shown in a broken line, of the column bonding pads which are integral with the remainder of the columns 21. Thus, in this embodiment the columns, the column bonding pads and the interconnect between the column bonding pads and the columns are formed and patterned from the first metal layer. 

With use of a passivation layer 29 a further embodiment allows for utilization of thin metal layers for both the first metal layer 18 and the second metal layer 20 to optimize yield and desired characteristics for the rows 21 and columns 22. The desired thickness of the bonding pads 30 and 31 being built up by a subsequent metal deposition. This is achieved by patterning the passivation layer 29 with a mask to form column bonding pad vias 32 and row bonding pad... 

Detector elements having three layer bonding pads are disclosed in JP-A-63148677. This structure allows bonding of the elements without damaging the HgCdTe detector material. 

Each detector 14 includes a detector crystal region 21 having a junction 22 which is connected to an indium bump 23. The indium bump bonds to the bonding pad 80 which is, in turn, bonded to a metallized trace 13. The sensitive area plane 12 is parallel to the plane formed by the edge of the supporting substrate and the multilayer thick/thin film interconnect pattern 50. 

In US-A-4720738 an HgCdTe layer is attached to a read-out substrate. Detector elements are connected to aluminium buses which are connected to bonding pads on the substrate via conductors that occupy holes through the HgCdTe layer. 

In this figure the silicon chip, the epoxy layer, the bonding area, and the mercury cadmium telluride layer are labeled 30, 31, 32 and 33, respectively. A detector element is connected to an aluminium bus line 34 which is insulated from the mercury cadmium telluride layer by a ZnS layer 36. A layer of indium 35 is located over the aluminium bus connection at the bonding pad region. 

Electrochemical functionalization - reductive coupling of diazonium salts The electrochemical functionalization of SWCNTs, deposited on an Si/Si02 substrate, with 4-nitrophenyl groups succeeded by the reduction of 4-nitrobenzene-diazonium salt in a mini-electrochemical cell with platinum counter and (pseu-do-)reference electrodes. A probe needle was used to make contact with one of the Au-Pd bonding pads on the substrate and allowed the application of an electric potential to the electrode (-1.3 V vs. Pt for >30 s) and to any SWCNTs underneath the electrode [177b]. 

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