Wafer processing method

Abstract

The present invention provides a wafer processing method. The wafer processing method for dividing a wafer having at least the second predetermined dividing lines among the first predetermined dividing lines and the second predetermined dividing lines that are formed as orthogonal to be formed as non-continuous into each device chip includes: a first direction modification layer forming step for forming the first direction modification layer inside the wafer along the first predetermined dividing lines; and, a second direction modification layer forming step for forming the second direction modification layer inside the wafer along the second predetermined dividing lines. The second direction modification layer forming step includes a T-junction processing step for forming a T-junction for the first predetermined dividing lines formed with the first direction modification layer to be crossed with the second predetermined dividing lines formed with the second direction modification layer therein. The T-junction processing step is to make the ends of a plurality of second direction modification layers from the lower layers to the upper layers formed as an inversed-step shape facing the previously formed first direction modification layers.

Description

technical field [0001] The invention relates to a processing method for silicon wafers, sapphire wafers and other wafers. Background technique [0002] In wafers such as silicon wafers and sapphire wafers, multiple devices such as ICs, LSIs, and LEDs are formed on the front side by dividing predetermined lines, and the wafers are divided into individual device chips by a processing device. The divided device chips are widely used in Various electronic devices such as mobile phones and personal computers. [0003] For dividing a wafer, a dicing method using a cutting device called a scribe is widely used. In the dicing method, the cutting tool is rotated at a high speed of about 30,000 rpm and cut into the wafer to cut the wafer, and the wafer is divided into individual device chips. It is about 30 μm. [0004] On the other hand, in recent years, a method of dividing a wafer into individual device chips using a laser beam has been developed and put into practical use. As ...

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Problems solved by technology

[0013] (1) When the second modified layer is formed inside the second planned dividing line intersecting the first planned dividing line in a T-shaped path, wherein the inside of the first planned dividing line parallel to one side of the device is first The first modified layer is formed, and as the converging point of the laser beam approaches the intersection point of the T-shaped path, a part of the laser beam used for processing the second planned dividing line is irradiated to the formed first modified layer, and laser light is generated. Reflection or scattering of the beam, light leakage into the device area, and the leakage of light damages the device and reduces the quality of the device.

[0014] (2) Conversely, before forming the modified layer in the first planned dividing line parallel to one side of the device, the modified layer is first formed inside the wafer along the second planned dividing line that meets the first planned dividing line in a T-shaped path. In the case of the modified layer, there is no modified layer at the intersection of the T-shaped roads that will block the progress of the cracks formed in the modified layer near the intersection of the T-shaped roads, causing the cracks to elongate from the intersection of the T-shaped roads 1 ~ 2mm to reach the device, there is a problem that the quality of the device is degraded

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