公开(公告)号：US5629216A

公开(公告)日：1997-05-13

申请号：US607626

申请日：1996-02-27

申请人： Witawat Wijaranakula ,  Sandra A. Archer ,  Dinesh C. Gupta

发明人： Witawat Wijaranakula ,  Sandra A. Archer ,  Dinesh C. Gupta

IPC分类号： C30B15/00 ,  H01L21/324

CPC分类号： C30B29/06 ,  C30B15/206 ,  Y10S148/003 ,  Y10S148/024 ,  Y10S148/127

摘要： A monitor wafer used to determine the cleanliness of a wafer fabrication environment requires a surface having a minimum of light scattering anomalies so that contamination deposited by the environment is not confused with light scattering anomalies initially on the monitor wafers. In the present invention, ingots of a single-crystal semiconductor are grown at a reduced pull rate and wafers produced from the ingot are annealed within a preferred temperature range that varies with the pull rate to produce wafers having reduced light-scattering anomalies on their surfaces. The number of light-scattering anomalies increases at a slower rate upon repetitive cleaning cycles than does the number of light-scattering anomalies of prior art wafers.

摘要翻译： 用于确定晶片制造环境的清洁度的监视器晶片需要具有最小光散射异常的表面，使得由环境沉积的污染物不会与最初在监视器晶片上的光散射异常相混淆。 在本发明中，以降低的拉伸速率生长单晶半导体的晶锭，并且从在锭产生的晶片在优选的温度范围内退火，该优选温度范围随拉伸速率而变化，以产生其表面上具有降低的光散射异常的晶片 。 在重复清洗周期时，光散射异常的数量以比现有技术的晶片的光散射异常的数量更慢。

公开(公告)号：US6005228A

公开(公告)日：1999-12-21

申请号：US920525

申请日：1997-08-29

申请人： Michael D. Dickens ,  Dinesh C. Gupta ,  Albert J. Highe

发明人： Michael D. Dickens ,  Dinesh C. Gupta ,  Albert J. Highe

IPC分类号： H05B1/02 ,  G05D23/19

CPC分类号： G05D23/1951 ,  G05D23/1919 ,  Y10T307/461

摘要： A thermally insulated substrate, e.g. a system of pipes, is maintained above a selected minimum temperature by means of one or more electrical heaters, preferably elongate self-regulating heaters. Each heater is successively switched on for a heat-up period and then off for a cool-down period. The durations of these periods are successively determined by reference to the ambient air temperature adjacent the substrate at an earlier time, e.g. at the end of the previous cool-down period. The method is particularly useful for temperature-maintenance systems in which a number of heaters are used to heat a complex system of pipes. The durations of the heat-up and cool-down periods for each heater (or for a group of two or more heaters) are separately determined by means of a single microprocessor. The microprocessor (a) is linked to an ambient air temperature sensor; (b) contains in its memory the relevant information about each heater, the pipes which it heats, and the thermal insulation surrounding the pipes; (c) is programmed to calculate the durations of the heat-up and cool-down periods; and (d) is linked to a number of switching means, one for each heater or group of heaters.

摘要翻译： 绝热基板，例如 通过一个或多个电加热器，优选细长的自调节加热器将管道系统保持在选定的最低温度以上。 每个加热器依次接通加热期，然后关闭冷却期。 这些时期的持续时间是通过参考较早时间的衬底附近的环境空气温度来连续地确定的。 在以前的冷静期结束时。 该方法对于其中使用多个加热器来加热管道的复杂系统的温度维持系统特别有用。 每个加热器（或一组两个或更多个加热器）的加热和冷却时段的持续时间通过单个微处理器单独确定。 微处理器（a）连接到环境空气温度传感器; （b）在其记忆中记载有关每个加热器，其加热的管道以及围绕管道的保温的相关信息; （c）被编程为计算加热和冷却时段的持续时间; 和（d）连接到多个切换装置，一个用于每个加热器或一组加热器。