Multilayer capacitor

#The present invention concerns multilayer ceramic capacitors having multiple capacitor plates which are terminated at a common face and more particularly, relates to improvements to multilayer capacitors resulting in greater flexibility in use and ease in manufacturing.

#The continuing objective of data processing equipment designers is to produce equipment having increased operating speed, reduced physical size and lower manufacturing cost.

#Advances in integrated circuit technology have gone a long way to satisfy this objective. One particular area of concentration is the capacitor. In an effort to get ever greater switching speed, circuit designers have gone to a decoupling capacitor which provides a low impedance path across the power supply to power the semiconductor chips without coupling noise into the signal wiring. The noise, if coupled, could cause errors in the computer functions. Such decoupling capacitors are discrete, i.e. separate from the chips. However, to retain the advantages of integrated form, the circuit designers have sought discrete capacitors of small size, maximum capacitance, high speed (rapid responding), low inductance, low resistance and reasonable cost.

#FIG. 1 is a perspective view of a multilayer capacitor according to the invention with the end non-conductive sheet portion removed.

#FIG. 1A is a modification of the multilayer capacitor shown in FIG. 1.

#FIG. 2 is an exploded perspective view of the multilayer capacitor of FIG. 1, with the top metallurgy removed.

#Referring now to the Figures in more detail and particularly referring to FIGS. 1 to 3 there is shown a multilayer capacitor, generally indicated by 10, according to the invention. The multilayer capacitor 10 comprises a plurality of laminae 12 wherein each of the laminae comprises a conductive plate portion 14 and a non-conductive sheet portion 16. At each end of the multilayer capacitor 10 there is at least one non-conductive sheet portion 18 which does not contain a conductive plate portion. There may, of course, be more than one non-conductive sheet portion 18, if desired. The conductive plate portion 14 has at least one tab 20 projecting to at least one surface edge 32 of the conductive plate portion 14 and lamina 12. An important feature of the invention is that the maximum number of tabs 20 per conductive plate portion 14 is limited so as to avoid excessive lateral congestion. The importance of this limitation will become more apparent hereafter.

#The laminae 12 are divided into different groups with all the laminae from each group having the same number and location of tabs and with the laminae from different groups differing by at least the location of tabs. That is, specifically referring to FIG. 2, there is one group of laminae represented by lamina 22 wherein the conductive plate portion 14, for example, has a tab 24 to the far right of the conductive plate portion 14 and another tab 26 laterally spaced therefrom. There is a second group of laminae represented by lamina 28 which, for example, has a tab 30 all the way to the far left of the conductive plate portion 14 and another tab 31 spaced laterally therefrom. By comparing the laminae from the group represented by lamina 22 and the laminae from the group represented by lamina 28, it can be seen that the conductive plate portions on each of the non-conductive sheet portions for each of the groups are distinctly different. While only two different groups are illustrated in FIG. 2, there may be three or more different groups as required. The ultimate limit on the number of different groups of laminae is the requirement to avoid excessive lateral congestion of the various tabs.

#For purposes of illustration, and not of limitation, all the conductive plate portions in FIG. 2 have two tabs projecting therefrom. There may, in fact, be a number of tabs other than two. It should be understood that all that is required according to the invention is that there be at least one tab projecting from each of the conductive plate portions.