JP2003257897A - Method for manufacturing semiconductor chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor chip in which failure of chips can be minimized. <P>SOLUTION: The method for manufacturing a semiconductor chip comprises a step for bonding a protective tape to cover the entire surface of a wafer having a large number of semiconductor devices formed on the surface thereof, a step for making thin the wafer by grinding, polishing or etching the rear surface of the wafer, a step for removing the protective tape bonded to the surface of the wafer, and a step for etching the wafer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin semiconductor device,
The present invention relates to a method of forming a semiconductor chip corresponding to the miniaturization and the multi-product type.

[0002]

2. Description of the Related Art A large number of semiconductor devices such as ICs are formed on a wafer through processes such as thin film formation, pattern exposure and etching, ion implantation and impurity diffusion, and after inspection of electrical characteristics, a back grinder is used. The wafer is thinned by grinding the back surface of the wafer using so-called back grinding, and is cut into individual chips by cutting with a dicing blade along the streets for partitioning a plurality of semiconductor chips. Alternatively, as in JP-A-5-74934, the wafer is diced to a predetermined depth by a dicing blade, and then back-ground to perform dicing into individual thin chips.
The above method will be described with reference to the sectional view of FIG.

In FIG. 2A, a protective tape 1 for preventing an influence on a semiconductor device in a back surface grinding step is adhered,
This is a part of a wafer 7 having a large number of semiconductor devices 2 formed on its front surface, and in order to make this wafer 7 a predetermined thickness, it is ground from the back surface of the wafer on which no semiconductor device is formed.

Next, as shown in FIG. 2B, a resin tape is adhered to the back surface of the wafer 3, the protective tape 1 is removed, and then the streets 8 for partitioning the chips 2 formed on the front surface of the wafer 3 are formed. A so-called dicing is performed to form the groove 5 along the resin tape 6 adhered to the back surface of the wafer.
And pull out the individual chips.

Further, as shown in FIG. 2 (c), after forming the groove 5 having a predetermined depth, the protective tape 1 is adhered to the wafer 7
Grind the back side of. Next, after the resin tape 6 is adhered to the back surface, the protective tape 1 is removed, the resin tape 6 is stretched, and individual chips are taken out.

[0006]

However, the semiconductor device used tends to be thinner and smaller with the downsizing of electric appliances. In addition, with the increasing variety of electrical appliances, there is a need for mass production of small variety to small quantity of multiple variety. In the above method, in order to meet such requirements, the dicing blade has a longer cutting distance due to miniaturization of the semiconductor chip, and since the wafer is thin, the wafer is chipped due to vibration of the dicing blade, and Increase the probability of cracking, and
There are problems that the probability of occurrence of chip cracks increases due to mechanical stress during dicing, and that the dicing blade breaks. In addition, since an interval is required for the dicing blades to enter the streets that divide the semiconductor chips, the number of semiconductor chips that can be obtained decreases, and the number of wafers required to manufacture a certain number of semiconductor chips increases. Therefore, there are problems such as an increase in production cost and an increase in production time. Therefore, it is an object of the present invention to provide a method of forming a semiconductor chip that can avoid damage to a thinned wafer and minimize defects of chips densely formed on the wafer.

[0007]

In order to achieve the above object, the present invention is a method for dividing a wafer having a large number of semiconductor devices formed on its surface into individual chips. That is, a step of adhering a protective tape so as to cover the entire surface of the wafer, a step of thinning the back surface of the wafer by grinding and / or polishing and / or etching, and a step of removing the protective tape adhered to the surface of the wafer. And a step of etching the wafer, which is a method for forming a thin chip.

To achieve the above object, a step of adhering a protective tape so as to cover the entire front surface of the wafer, a step of thinning the back surface of the wafer by grinding and / or polishing and / or etching, and a cutting step. Bonding the resin tape to cover the entire back surface of the wafer,
A method of forming a thin chip, comprising: a step of removing a protective tape adhered to the surface of the wafer; a step of etching the wafer; and a step of applying pressure to the wafer to divide into individual chips. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view for explaining a method of forming a semiconductor chip according to the present invention in the order of steps. The steps will be described below in order.

FIG. 1A shows a step of adhering a protective tape so as to cover the entire surface of a wafer having a large number of semiconductor devices 2 formed on the surface, and grinding the back surface of the wafer by grinding or polishing. It is a figure which shows the wafer of the state which removed the damage layer produced by and was thinned. The protective tape 2 protects the semiconductor device 2 on the wafer from the pressure received during back grinding, and also acts as a reinforcing material for a particularly thin wafer having a thickness of about 20 to 50 microns at this point. FIG. 1B shows the protective tape 2 shown in FIG.
Is removed, the street portion is etched, and then divided into individual chips. Here, etching is used as a method of dividing the chip, but so-called anisotropic etching is used in which the etching rate varies depending on the crystal plane orientation using the surface protection film of the chip or the oxide film as a mask. . By using this method, the chipping of the wafer due to the vibration of the dicing blade, which is a problem in dividing the chip using the blade, and the occurrence of chip cracks due to the occurrence of cracks and mechanical stress, and the damage of the dicing blade, etc., is eliminated. Since it is not necessary to provide an interval for the dicing blade to enter the streets that divide the semiconductor chips, the number of semiconductor chips that can be taken out from a wafer of the same size increases.

Next, FIG. 1C shows a state of the wafer after the resin tape 6 having elasticity is adhered to the entire back surface of the wafer, the protective tape 2 is removed, and the street portion is etched. Here, as the material of the protective tape 2,
For example, use a resin adhesive sheet or thermosetting adhesive whose adhesive strength decreases when irradiated with ultraviolet rays, or a side chain crystalline polymer adhesive that changes between a crystalline state and an amorphous state at a set temperature. If so, this protective tape 2 can be easily removed.

The wafer shown in FIG. 1C is divided into individual chips along a groove formed by etching by applying pressure. After that, the resin tape adhered to the entire back surface of the wafer is stretched to widen the intervals between the individual chips so that the individual chips can be easily taken out.

[0014]

As described above, according to the present invention,
Since etching is used as a method of dividing the chips, there are no problems such as chipping of the wafer, occurrence of cracks, occurrence of chip cracks due to mechanical stress, and damage to the dicing blade. Further, since the street width that divides the semiconductor chips can be narrowed, the number of semiconductor chips to be taken increases, and the production cost and the production time can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, which is a cross-sectional view illustrating a method of forming a semiconductor chip of the present invention in the order of steps.

FIG. 2 is a cross-sectional view for explaining a conventional method for forming a semiconductor chip in the order of steps in an example of a conventional method for forming a semiconductor chip.

[Explanation of symbols]

1 protective tape 2 Semiconductor device 3 Wafer after backside grinding 4 ground wafer 5 Grooves formed by anisotropic etching 6 backside tape 7 Wafer before backside grinding 8 Streets that divide between semiconductor chips 9 Grooves formed by dicing

Claims (3)

[Claims] 1. A method of dividing a wafer having a large number of semiconductor devices formed on its surface into individual chips, the first step of adhering a protective tape so as to cover the entire surface of the wafer; Second step of thinning the back surface by grinding, and third step of removing the protective tape adhered to the front surface of the wafer
And a fourth step of etching the wafer, the method of forming a semiconductor chip. 2. The formation of a semiconductor chip according to claim 1, further comprising a step of bonding a resin tape so as to cover the entire back surface of the wafer ground for thinness in the second step. Method. 3. The method according to claim 1, further comprising a step of applying pressure to the wafer to divide it into individual chips after etching the wafer in the fourth step.
A method of forming a semiconductor chip according to claim 1.