| 摘要 |
<p>The present invention relates to a method and means for making a temperature-compensated bedding for chips on printed boards, at which a temperature-compensated mean is totally or partly recessed in a carrier in the printed board. The chip is placed over the temperature-compensated mean. The temperature-compensated mean includes a piece of metal recessed in the carrier under the chip. A layer of copper is fixed against the upper side of the carrier and the upper side of the metal piece. The thickness of the copper layer and the thickness of the metal piece are dimensioned so that the resulting coefficient of linear expansion at the upper side of the copper layer is equally big as or a bit bigger than the coefficient of linear expansion of the chip. The temperature-compensated mean can as an alternative to the above include a module recessed in the carrier under the chip. A thin layer of dielectric is fixed against the carrier, so that the coefficient of linear expansion of the dielectric layer do not appreciably affect the resulting coefficient of linear expansion of the temperature-compensated mean.</p> |
