Wafer filling and thinning processing method

Abstract

The invention relates to the technical field of semiconductors, in particular to a wafer filling and thinning processing method, which comprises the following steps of: 1, cutting a circle of step with the width gt at the edge of a wafer; the thickness is 3-9mm, and the depth is gt; the particle size is 20-36 [mu] m; 2, UV glue is coated on the periphery of the wafer, the step is filled, and the filled UV glue is flush with the front face of the wafer; step 3, curing the UV glue to form a wafer with a full diameter size; and 4, after the grinding table board adsorbs the full-diameter-size wafer, grinding and thinning processing is carried out. Compared with the prior art, after the step at the edge of the wafer is filled with the UV glue, the full-diameter wafer is formed, the problems of wafer breakage and vacuum leakage during grinding caused by the step of the wafer are solved, the method is particularly suitable for the requirement for the grinding thickness of the ultrathin wafer, the operability is better, the grinding quality is improved, the packaging yield is increased, and the production cost is reduced. The abnormity processing time of the machine due to vacuum alarm is reduced, and the utilization rate of the machine is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a wafer filling and thinning process method. Background Technology

[0002] Current wafers use a ring-cutting process, which creates a step around the edge of the front side of the wafer. The methods for thinning the wafer edge step include, in sequence, wafer lamination, pre-grinding, hidden dicing, grinding, lamination, film removal, and film expansion.

[0003] As wafer edge steps become wider and deeper, steps with widths exceeding 3-9 mm and depths exceeding 20-36 μm appear. During the grinding and thinning process, conventional grinding tables may trigger vacuum leakage alarms, and there is also a significant risk of wafer edge breakage during grinding.

[0004] Therefore, it is necessary to design a wafer filling and thinning process to fill the recessed steps with a certain width and depth around the wafer, and avoid edge breakage during the grinding and thinning process. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wafer filling and thinning process method to fill the recessed steps with a certain width and depth around the wafer, thereby avoiding edge breakage during the grinding and thinning process.

[0006] To achieve the above objectives, the present invention provides a wafer filling and thinning process, comprising the following steps: Step 1, cutting a step around the edge of the wafer, the step having a width >3~9mm and a depth >20~36um; Step 2, coating the wafer with UV adhesive around its perimeter to fill the step, the UV adhesive being flush with the front side of the wafer; Step 3, curing the UV adhesive to form a wafer of full diameter; Step 4, after the full diameter wafer is adsorbed onto the grinding table, grinding and thinning processing is performed.

[0007] The UV adhesive is composed of photosensitive resin.

[0008] The specific method for curing the UV adhesive is as follows: using a UV lamp to irradiate and cure the photosensitive resin.

[0009] The grinding and thinning process includes pre-grinding, hidden cutting, grinding, film application, and film expansion.

[0010] Compared with the prior art, this invention uses UV glue to fill the steps at the edge of the wafer to form a wafer of full diameter, which solves the problems of wafer breakage and vacuum leakage during grinding caused by wafer steps. It is especially suitable for grinding ultra-thin wafers with thickness requirements, has better workability, improves grinding quality, increases packaging yield, and reduces the abnormal handling time caused by vacuum alarms, thereby improving the utilization rate of the machine. Attached Figure Description

[0011] Figure 1 This is a front view of the wafer after circumferential cutting according to the present invention.

[0012] Figure 2 This is a side view of the wafer after circumferential cutting according to the present invention.

[0013] Figure 3 This is a schematic diagram of the wafer step-filling UV adhesive of the present invention. Detailed Implementation

[0014] The present invention will now be further described with reference to the accompanying drawings.

[0015] See Figure 1 , Figure 2 and Figure 3 This invention is a wafer filling and thinning process, comprising the following steps: Step 1, cutting a step 2 around the edge of wafer 1, the step 2 having a width >3~9mm and a depth >20~36um; Step 2, coating UV adhesive 3 around wafer 1 to fill the step 2, the filling UV adhesive 3 being flush with the front side of wafer 1; Step 3, curing UV adhesive 3 to form a wafer of full diameter; Step 4, after the full diameter wafer is adsorbed on the grinding table, grinding and thinning processing is performed.

[0016] UV adhesive 3 is composed of photosensitive resin.

[0017] The UV adhesive 3 is cured as follows: the photosensitive resin is cured by irradiating it with a UV lamp.

[0018] The grinding and thinning process includes pre-grinding, hidden cutting, grinding, film application, and film expansion. After covering with UV adhesive 3, no height difference is generated on the original wafer front side, eliminating the need for a protective film and allowing for direct grinding and thinning, thus reducing the number of processing steps and equipment costs.

[0019] UV adhesive 3 is only applied to the ineffective areas around wafer 1, so it does not need to be removed, eliminating the need for the film removal step in the original process.

[0020] This invention uses UV adhesive to fill the steps at the edge of the wafer, forming a full-diameter wafer. This solves the problems of wafer breakage and vacuum leakage during grinding caused by wafer steps. It is particularly suitable for grinding ultra-thin wafers with required thickness, offering better workability, improved grinding quality, increased packaging yield, and reduced processing time due to vacuum alarms, thus improving machine utilization. This invention can be applied to all stepped wafer packaging processes.

Claims

1. A wafer thinning process, characterized in that: The process includes the following steps: Step 1, cut a step (2) around the edge of the wafer (1), with the width of the step (2) being >3~9mm and the depth being >20~36um; Step 2, coat the wafer (1) with UV adhesive (3) around the edge to fill the step (2), and the UV adhesive (3) is flush with the front side of the wafer (1); Step 3, cure the UV adhesive (3) to form a wafer of full diameter; Step 4, after the full diameter wafer is adsorbed on the grinding table, perform grinding and thinning processing.

2. The wafer filling and thinning process according to claim 1, characterized in that: The UV adhesive (3) is composed of photosensitive resin.

3. The wafer filling and thinning process method according to claim 1, characterized in that: The curing of UV adhesive (3) is specifically carried out as follows: UV lamp tube is used to irradiate and cure the photosensitive resin.

4. The wafer filling and thinning process according to claim 1, characterized in that: The grinding and thinning process includes pre-grinding, hidden cutting, grinding, film application, and film expansion.

Images