Apparatus and method for retaining a semiconductor wafer during testing

An apparatus for retaining a semiconductor wafer on a first surface of a chuck, comprising:

• a first chamber positioned adjacent to the chuck and disposed below the first surface of the chuck;
• a first elongate shaft having a first end positioned above the first surface of the chuck and a second end positioned inside the first chamber;
• a first retainer member connected to the first end of the first shaft and which extends over the first surface of the chuck and a portion of the semiconductor wafer resting thereon in order to retain the semiconductor wafer thereagainst when the first retainer member is in a closed position;
• and
• a vacuum source coupled to the first chamber to provide suction inside the first chamber to pull the first shaft deeper into the first chamber so that the first retainer member moves from an open position where it is spaced apart from the semiconductor wafer to the closed position where it contacts the portion of the semiconductor wafer.

An apparatus for retaining a semiconductor wafer on a first surface of a chuck, comprising:

• first and second chambers positioned adjacent to a perimeter of the chuck and disposed below the first surface of the chuck;
• first and second elongate shafts each having a first end positioned above the first surface of the chuck and a second end positioned inside the first and second chambers, respectively;
• first and second retainer members connected to the first ends of the first and second shafts, respectively, which extend over the first surface of the chuck and portions of the semiconductor wafer resting thereon in order to retain the semiconductor wafer thereagainst when the first and second retainer members are in a closed position;
• and
• a vacuum source coupled to the first and second chambers to provide suction inside the first and second chambers to pull the first and second shafts deeper into their respective chambers so that the first and second retainer members move from an open position where they are spaced apart from the semiconductor wafer to the closed position where they contact portions of the semiconductor wafer.

A retaining apparatus for retaining a semiconductor wafer on a first surface of a chuck, comprising:

• first, second, third and fourth elongate shafts each positioned adjacent to a perimeter of the first surface of the chuck and so that a lengthwise axis of each shaft is substantially perpendicular to the first surface of the chuck, the first and second shafts being located on one side of a diameter of the first surface of the chuck and the second and third shafts being located on another side of the diameter of the first surface of the chuck;
• first, second, third and fourth retainer members each connected to a first end of the first, second, third and fourth shafts, respectively, the retainer members extending over the first surface of the chuck and portions of the semiconductor wafer resting thereon in order to retain the semiconductor wafer thereagainst when the retainer members are in a closed position;
• first, second, third and fourth chambers which each receive a second end of the first, second, third and fourth shafts, respectively;
• and
• a vacuum source coupled to the first, second, third and fourth chambers to provide suction inside the chambers to pull the first, second, third and fourth shafts deeper into their respective chambers so that the retainer members move from an open position where they are spaced apart from the semiconductor wafer to the closed position where they contact portions of the semiconductor wafer.

A semiconductor wafer test station, comprising:

• a base;
• a chuck mounted on the base, the chuck having a substantially planar first surface for receiving a wafer;
• a first block having a first chamber formed therein, the first block being positioned adjacent to the chuck and disposed below the first surface of the chuck;
• a first elongate shaft which extends into the first chamber and that is positioned so that its lengthwise axis is substantially perpendicular to the first surface of the chuck, the first shaft having a helical thread therearound which engages with a complementary helical thread formed on an inner surface of the first chamber so that the first shaft rotates about its lengthwise axis as it moves within the first chamber in a direction collinear with its lengthwise axis;
• a first retainer member connected to the first shaft at a point such that the first retainer member extends over the first surface of the chuck to sandwich a portion of the wafer therebetween when the first retainer member is in a closed position;
• and
• a vacuum source coupled to the first chamber to provide suction inside the first chamber to pull the first shaft deeper into the first chamber so that the first retainer member moves from an open position where it is spaced apart from the first surface of the chuck to the closed position where it contacts a portion of the wafer, the first shaft rotating about its lengthwise axis as it moves from the open position to the closed position.

A method of retaining a semiconductor wafer on a first surface of a chuck, comprising the steps of:

• creating a vacuum inside of a first chamber which is positioned adjacent to the chuck and disposed below the first surface of the chuck;
• using the vacuum created inside of the first chamber to pull a first elongate shaft deeper into the first chamber, the first elongate shaft being positioned substantially perpendicular to the first surface of the chuck and having a first end which extends thereabove;
• and
• rotating the first shaft about its lengthwise axis as it is pulled deeper into the first chamber so that a first retainer member connected to the first end of the first shaft rotates from an open position where it does not extend over the first surface of the chuck to a closed position where it does extend over the first surface of the chuck.

A method of testing a semiconductor wafer, comprising the steps of:

• placing the semiconductor wafer on a first surface of a chuck;
• creating a vacuum inside of a first chamber which is positioned adjacent to the chuck and disposed below the first surface of the chuck;
• using the vacuum created inside of the first chamber to pull a first elongate shaft deeper into the first chamber, the first elongate shaft being positioned substantially perpendicular to the first surface of the chuck and having a first end which extends thereabove;
• rotating the first shaft about its lengthwise axis in a first direction as it is pulled deeper into the first chamber so that a first retainer member connected to the first end of the first shaft rotates from an open position where it does not extend over the first surface of the chuck to a closed position where it extends over the first surface of the chuck and contacts a portion of the semiconductor wafer to retain it on the first surface of the chuck;
• probing the semiconductor wafer with a testing apparatus;
• and
• moving the first shaft further out of the first chamber so that the first retainer member moves from the closed position to the open position.