Method and eletrostatic transfer stamp for transferring semiconductor dice using electrostatic transfer printing techniques
View Patent ↗A transfer stamp that can be charged with a spatial pattern of electrostatic charge for picking up selected semiconductor dice from a host substrate and transferring them to a target substrate. The stamp may be bulk charged and then selectively discharged using irradiation through a patterned mask. The technique may also be used to electrostatically transfer selected semiconductor dice from a host substrate to a target substrate.
1. A method for transferring semiconductor dice from a host substrate to a target substrate, comprising the steps of:
electrostatically charging regions of a selected one of a transfer stamp or a target substrate;
transferring semiconductor dice from a host substrate to said electrostatically charged regions of the selected one of the transfer stamp or target substrate by the application of the electrostatic force of the charged regions to the semiconductor dice when the host substrate is positioned adjacent to the selected one of the transfer stamp or target substrate; and
releasing the semiconductor dice onto the target substrate from the transfer stamp, when the selected one is the transfer stamp, by at least removing the electrostatic charge of the electrostatically charged regions or providing an adhesive force between the semiconductor dice and the target substrate that is greater than the electrostatic force between the semiconductor dice and the electrostatically charged regions,
wherein electrostatically charging regions of the selected one of the transfer stamp or the target substrate comprises (i) bulk electrostatic charging the transfer stamp or the target substrate and (ii) thereafter, erasing charge therefrom by exposing the selected one of the transfer stamp or the target substrate to optical radiation through an optical mask with opaque portions overlying and shielding the electrostatically charged regions from having their charge dissipated by the optical radiation.
2. The method of claim 1 wherein the selected one of the transfer substrate or target substrate has spaced apart mesas formed thereon and defining the electrostatically charged regions.
3. A method for transferring semiconductor dice from a host substrate to a target substrate, comprising the steps of:
electrostatically charging regions of a transfer stamp by a process comprising (i) bulk electrostatic charging of the transfer stamp and (ii) thereafter, erasing charge from the transfer stamp by exposing the transfer stamp to optical radiation through an optical mask with opaque portions overlying and shielding the electrostatically charged regions from having their charge dissipated by the optical radiation;
removing semiconductor dice from a host substrate using the electrostatically charged regions of the transfer stamp; and
releasing the semiconductor dice from the transfer stamp onto the target substrate by at least removing the electrostatic charge of the stamp or providing an adhesive force between the semiconductor dice and the target substrate that is greater than the electrostatic force between the semiconductor dice and the transfer stamp.
4. The method of claim 3 wherein the transfer stamp has spaced apart mesas formed on a light-transmitting substrate and a series of strata overlying the mesas and having a charge transfer outer layer on the mesas defining the electrostatically charged regions.
5. The method of claim 3 wherein said removing the semiconductor dice from the host substrate to the transfer stamp occurs when the transfer stamp is positioned such that the electrostatically charged regions are placed adjacent to the semiconductor dice.
6. The method of claim 1 wherein the transfer stamp has spaced apart mesas formed on a substrate and a series of strata overlying the mesas and having a charge transfer outer layer on the mesas defining the electrostatically charged regions.
7. The method of claim 6 wherein said removing the semiconductor dice from the host substrate to the transfer stamp occurs when the transfer stamp is positioned such that the electrostatically charged regions on the mesas are placed adjacent to the semiconductor dice.