JPS62151306A - Dicing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention is a wafer blade dicing method.

In particular, the present invention relates to a grade dicing method capable of dicing wafers without causing electrostatic damage to circuits and preventing contamination of the wafer surface.

[Technical background of the invention and its problems]

Generally, in the manufacturing process of semiconductor products, when blade dicing of wafers is performed, the static electricity generated during dicing can cause electrostatic damage to circuit elements, and this risk is particularly important for KMOS type products. Also, silicon cutting powder generated during dicing adheres to the wafer,
It contaminates the surface of circuit elements, which is a big problem, especially in semiconductor imaging products and ultraviolet-erasable memory products.

Therefore, conventional dicing methods to prevent electrostatic damage of circuit elements include placing the wafer on a grounded metal dicing table and performing half-cut dicing, and dicing the wafer by using a conductive adhesive on a conductive base material. There are methods such as fixing the wafer and performing full-cut dicing, or using conductive water as cutting water when performing full-cut dicing with the wafer attached to an adhesive tape or the like.

In addition, conventional dicing methods for preventing contamination on the surface of circuit elements include coating the entire surface with resist, coating the surface with thin adhesive tape, or dicing without coating with a protective film and then cleaning with a jet shower. There is a way to do it.

What are the problems with these conventional dicing methods?

When half-force die sinking is performed on a metal dicing table, it is extremely difficult to remove all wafers from the table after dicing, and there is a high risk of wafer breakage. Further, since half-cut dicing is used, subsequent cracking is required, and defects such as chipping defects during cracking and surface scratches on the pellet due to adhesion of wafer debris may occur.

When performing full-cut dicing with the wafer fixed with conductive adhesive, the wafer cannot be expanded after dicing, so there is a risk of damaging adjacent pellets when taking out the pellets. Processing steps are also required.

The method of pasting the wafer on adhesive tape and performing siful cut dicing using conductive cutting water has the advantage of allowing the wafer to expand after dicing, but it is also possible to use city water with a lot of impurities as the conductive cutting water. Alternatively, pure water with high electrical resistance is added with impurities that have little effect on semiconductors to make it conductive, so in the former case, dirt on the surface of the circuit element becomes a problem, and in the latter case, cutting water production equipment is used. There are problems such as the need for

Methods for preventing dirt from being removed from the surface of circuit elements are generally used in combination with the dicing method described above, but each method has its advantages and disadvantages. The resist coating method requires a post-treatment resist stripping process, and due to the organic solvent used at this time or resist stripping, it cannot be used in combination with the above-mentioned dicing method. In the case of the dicing method used, there are problems such as the need to remove the resist after taking out individual pellets. Sincerely,
The jet shower cleaning method after dicing has the disadvantage that water with a high electrical resistance value is not suitable as cleaning water, and that the same conductive cutting water as described above must be used.

[Purpose of the invention]

This invention improves the drawbacks of the above-mentioned conventional wafer blade dicing method, such as difficulty in working, lower yield, and addition of auxiliary equipment due to electrostatic damage prevention and surface stain prevention methods. An object of the present invention is to provide a dicing method that does not cause electrostatic damage and facilitates post-dicing processing steps.

[Summary of the invention]

In order to prevent static electricity damage to circuit elements during blade dicing of wafers, it is necessary to release the static electricity generated during dicing to the outside, and for this purpose, it is essential to always create a path for electricity to flow. Normally, when dicing is performed by fixing the wafer directly on a grounded metal table, there is no problem because the wafer is grounded, but when performing full-cut dicing of the wafer, it is necessary to prevent the pellets from scattering after dicing. In order to do this, they are pasted onto adhesive tape or the like beforehand and diced. The present invention proposes a method for maintaining the wafer in a grounded state and dissipating static electricity to the outside even in such a dicing method using adhesive tape. Paste it on the back side of the .

Next, a transparent adhesive tape coated in the same way is attached to the surface of the wafer. This goal can be achieved by fitting the upper and lower conductive coated adhesive tapes into a metal ring, fixing them on a grounded metal table, and performing dicing over the adhesive tapes affixed to the surface. It will be done.

〔Effect of the invention〕

Unlike conventional dicing methods, the dicing method of the present invention is a method in which a conductive adhesive tape is applied to the entire top and bottom surfaces of the wafer, and the wafer is diced together with the adhesive tape on the top surface, so the wafer is electrically perfect. Since dicing is performed while sealed and grounded, there is no need to perform dicing using conductive cutting water, which is conventionally done, and electrostatic damage to circuit elements can be completely prevented.

In addition, since adhesive tape is used on the underside of the wafer,
The dicing depth can be selected from any method from half-cut dicing to full-cut dicing, and the wafer can be expanded after dicing, thereby preventing defects during the pellet removal process.

Furthermore, since dicing is performed with the adhesive tape attached to the top surface of the pellets, it is not only possible to completely prevent dirt from being removed during dicing, but also to eliminate the cleaning process in the post-process. If the gold is not removed, the pellet surface can be protected no matter what process is carried out, so the yield is significantly improved.

[Embodiments of the invention]

The present invention prevents electrostatic damage to devices by performing dicing using conductive adhesive tape.

The adhesive tape used for normal dicing is made of vinyl chloride-based material and therefore has no conductivity. A conductive coating is used. These electrically conductive films may be obtained, for example, by ultrathin metal coatings or by coatings such as transparent metal oxide thin films.

The figure is a schematic cross-sectional view of the embodiment.
The ends are sandwiched together by a metal ring 4 to ensure complete electrical continuity. Then, the Ueno τ1 stretched on these metal rings 4 is fixed to a dicing table 5 grounded by a ground wire 7, and diced. Here, the dicing calf 6 is formed with the adhesive tape 2 still attached.

[Brief explanation of drawings]

The figure is a sectional view showing an embodiment of the present invention. In fig. DESCRIPTION OF SYMBOLS 1... Wafer, 2... Adhesive tape, 3... Conductive film, 4... Gold scrap ring, 5... Dicing table, 6... Dicing calf, 7... Ground wire . Agent Patent Attorney Nori Chika Yudo Kikuo Takehana

Claims (1)

[Claims] A wafer blade dicing method characterized by dicing the wafer by fixing the top and bottom surfaces of the wafer with grounded conductive adhesive tape.