____________ used to align wafers with the mask in mask aligner.
I. Linear translation in horizontal plane
II. Rotational motion
III. Linear translation in vertical direction
IV. Spiral translation
The correct answer for aligning wafers with the mask in a mask aligner is a combination of the following three methods:
I. Linear translation in the horizontal plane: This method involves moving the wafer and the mask horizontally in order to line up the desired features on the mask with those on the wafer. The alignment can be done by using mechanical stages or actuators to move either the wafer or the mask. This translation allows for precise positioning of the mask and the wafer.
II. Rotational motion: Rotary stages or actuators are used to rotate either the wafer or the mask during alignment. This is particularly useful when the features on the mask and the wafer need to be properly aligned through rotation, such as when aligning circular or angular patterns.
III. Linear translation in the vertical direction: This method involves moving the wafer and the mask vertically, perpendicular to the horizontal plane, to achieve proper alignment. This vertical translation is necessary to ensure that the mask is in close contact with the wafer surface, eliminating any gaps or misalignments.
IV. Spiral translation: Spiral translation is not typically used for aligning wafers with the mask in a mask aligner. It refers to a motion where the wafer and the mask are moved in a spiral pattern to achieve alignment. This method is not widely used in mask alignment processes and is not a common technique for aligning wafers with masks.
The techniques used to align wafers with the mask in a mask aligner are as follows:
I. Linear translation in horizontal plane: This involves moving the wafer and/or the mask holder in a straight line horizontally to achieve alignment. This can be done manually or with the help of motorized stages.
II. Rotational motion: Rotational motion is used to align the wafer and the mask by rotating them relative to each other. This can be done by manually adjusting the position or by using motorized stages.
III. Linear translation in vertical direction: Vertical translation is used to adjust the distance between the wafer and the mask in order to achieve optimal alignment. This can be done by manually adjusting the position or by using motorized stages.
IV. Spiral translation: In some cases, a spiral pattern is used for alignment. This involves moving the wafer and/or the mask in a spiral trajectory until alignment is achieved. This can be done manually or with the help of motorized stages.
Overall, a combination of these techniques is commonly used in mask aligners to align wafers with the mask accurately and precisely.