JPH07283179A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make a semiconductor wafer thin by grinding its rear keeping it high in mechanical and physical strength even if it is large in diameter by a method wherein the semiconductor wafer is divided into a few pieces before its rear is ground. CONSTITUTION:A semiconductor wafer 1 previously subjected to an element circuit forming process is subjected to a final check, and then chips are subjected to a testing process. After testing, the semiconductor wafer 1 is divided into a few pieces by cutting. The wafer 1 is cut by a diamond cutter through a scribing method or by a laser cutter through a fusion cutting method or by a diamond grinding stone through a dicing method, and the semiconductor wafer 1 is divided into four pieces. After the wafer 1 is cut, the element circuit forming surface of the wafer 1 is pasted on a fixing member 3 and fixed, and the rear of the semiconductor wafer 1 is ground by a grinder 2. The semiconductor wafer 1 split into four pieces is set on a grinder 2 and ground optional in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of semiconductor manufacturing, and more particularly to a wafer back surface processing technology and a packaging technology, which are effectively applied to, for example, a wafer back surface grinding technology and an ultra-thin packaging technology. It is something.

[0002]

2. Description of the Related Art Conventionally, a semiconductor wafer which has undergone a device circuit forming process has a back surface of the semiconductor wafer cut to have an arbitrary thickness in order to improve the dividing property, the resistance, and the heat dissipation property. Later, it is divided into individual chips and mounted on a package. Regarding the backside processing of semiconductor wafers, for example, chemical etching has been the mainstream in the past, but with the increase in diameter of wafers, grinding methods and lapping methods that mechanically shave using fixed abrasives or loose abrasives are used. Is used.

FIG. 7 shows a conventional back surface grinding method, and FIG. 8 shows a conventional semiconductor device manufacturing flow including a back surface grinding step.
The rear surface of the semiconductor wafer 4 which has completed the element circuit forming step is ground by a grinder 5 to an arbitrary thickness. After the completion of grinding, a wafer completion inspection and a wafer testing are performed, and the chips are divided into individual chips in a dicing process. In the assembly process, only the chips that are good in wafer testing are used, and die bonding, wire bonding, sealing,
The semiconductor device is completed by cutting and molding the leads.

A method of grinding a semiconductor substrate is described in, for example, Japanese Patent Publication No. 63-12741.

[0005]

However, since the weight of the wafer itself increases as the diameter of the wafer further increases, the mechanical and physical strength is impaired by thinning the back surface by grinding. It may crack and become defective. Also in terms of uniformity, the wafer is likely to warp, and it has been impossible to perform accurate grinding.

Further, recently, the semiconductor package has been made thinner, and the chip tends to be made thinner accordingly, so that the mechanical and physical strengths are significantly lowered. for that reason,
It is technically and
It is difficult from the viewpoint of productivity, and it has led to delays in the development and commercialization of ultra-thin packages.

Therefore, an object of the present invention is to provide a technique capable of thinly grinding the back surface while maintaining the mechanical and physical strength even if the diameter of the semiconductor wafer is increased.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows. That is, a method of manufacturing a semiconductor device in which individual chips are mounted in a semiconductor package after grinding the back surface of a semiconductor wafer that has completed the element circuit forming step, and before the back surface of the semiconductor wafer is ground. Is divided into a plurality of steps.

[0010]

By dividing the semiconductor wafer into a plurality of pieces before grinding the back surface of the semiconductor wafer, the thickness of the divided individual wafers is increased, so that the mechanical and physical strength is increased. Therefore, even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength.

[0011]

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a flowchart showing a method for grinding a back surface of a semiconductor wafer according to the present invention, and FIG. 2 is a flowchart showing a method for manufacturing a semiconductor device using the method shown in FIG. The semiconductor wafer 1 that has completed the element circuit forming process is subjected to a wafer completion inspection, and then subjected to wafer testing in which the electrical characteristics of individual chips are measured using a tester and a prober. After the completion of the wafer testing, the semiconductor wafer 1 is preliminarily cut into wafers. Wafer cutting, for example,
A scribing method using a diamond cutter, a melting cutting method using a laser cutter, or a dicing method using a dicing device using a diamond grindstone is used. In this embodiment, one semiconductor wafer 1 is divided into four as shown in FIG. By this wafer cutting, it is possible to prevent cracks due to the increase in diameter of the semiconductor wafer and warpage due to stress. After the wafer is cut, the element circuit forming surface of the semiconductor wafer 1 is attached and fixed to the fixing member 3, and the back surface of the semiconductor wafer is ground using the grinder 2. The four-divided semiconductor wafer 1 is set in a grinder and ground to an arbitrary thickness. By dividing the semiconductor wafer into small blocks and grinding the back surface in this way, the thickness of the wafer with respect to the area of one block of the semiconductor wafer increases, so that the physical strength of the wafer increases and the factor of cracking is mitigated. Therefore, the semiconductor wafer can be ground thinner than before.

Next, the back surface of the semiconductor wafer 1 whose back surface has been ground is fixed to a fixing tape of a carrier jig, and the carrier jig is set in a dicing device to be divided into individual chips. Each chip goes through an assembly process such as die bonding process, wire bonding process,
The semiconductor device is completed by sealing and cutting.

According to this embodiment, since the semiconductor wafer is divided into a plurality of pieces before the back surface of the semiconductor wafer is ground, the thickness of the divided individual wafers increases with respect to the area of the semiconductor wafer. Strength increases. Therefore,
Even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength. Also,
Since the warp of the semiconductor wafer due to stress is also alleviated,
It can grind uniformly and accurately.

[0014]

[Embodiment 2] In this embodiment, a part of the process sequence of Embodiment 1 is modified. FIG. 3 is a diagram showing a flowchart of the process. After the completion of the device circuit forming process, the semiconductor wafer 1 is subjected to a wafer completion inspection and then fixed by fixing the back surface to a fixing tape, for example, as shown in FIG. A diamond cutter, a laser cutter, a dicing device, or the like is used for wafer cutting. Next, the element circuit formation surface of the semiconductor wafer 1 divided into four is fixed by the fixing member 3, and the back surface is ground by a grinder to an arbitrary thickness. By dividing the semiconductor wafer into small blocks and grinding the back surface in this way, the thickness of the wafer with respect to the area of one block of the semiconductor wafer increases, so that the physical strength of the wafer increases and the factor of cracking is mitigated. Therefore, the semiconductor wafer can be ground thinner than before, and since the warpage due to stress is mitigated, it can be ground uniformly and accurately. The semiconductor wafer 1 whose back surface has been ground is then attached to a carrier jig, and wafer testing is performed to measure the electrical characteristics of individual chips using a tester and a prober. After the completion of the wafer testing, the semiconductor wafer 1 is set together with the carrier jig in the dicing device and cut into individual chips. Individual chips are subjected to an assembly process such as a die bonding process and a wire bonding process, and then sealed and cut to form a semiconductor device.

According to the present embodiment, by dividing the semiconductor wafer into a plurality of pieces before grinding the back surface of the semiconductor wafer, the thickness of the divided individual wafers increases with respect to the mechanical and physical areas. Strength increases. Therefore,
Even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength. Also,
Since warpage due to stress is alleviated, uniform and accurate grinding can be performed. Further, since wafer testing is performed after the back surface is ground, it is possible to measure the electrical characteristics of the wafer in a state closest to the final product.

[0016]

[Embodiment 3] In this embodiment, a method of grinding the back surface after a dicing step for cutting the semiconductor wafer 1 into individual chips will be described. FIG. 4 shows a method of manufacturing the semiconductor device of this embodiment, and FIG. 5 shows a flow chart of this embodiment. The semiconductor wafer on which the element circuits have been formed is subjected to a wafer completion inspection, and wafer testing is performed to measure the electrical characteristics of individual chips using a tester and a prober. After wafer testing, semiconductor wafer 1
Is fixed to a carrier jig and cut into individual chips 1b by using, for example, a dicing device. Next, the element circuit forming surface is attached to the fixing member 3 while the positional relationship of the individual chips 1b on the semiconductor wafer 1 before being diced is maintained, and the back surface of each of the chips 1b is attached using the grinder 2. Grind to the desired thickness. By grinding the back surface after dicing the semiconductor wafer in this manner, the thickness with respect to the area of the chip increases, so the physical and mechanical strength of the chip increases, and the factors of warpage and cracking are alleviated. Therefore, it is possible to grind thinner than the back surface in the wafer state and to grind uniformly and accurately.

The individual chips 1b whose back surface has been ground are subjected to an assembly process such as a die bonding process and a wire bonding process, and then sealed and cut to form a semiconductor device.

According to this embodiment, since the back surface of each chip is ground after the dicing process is completed, the thickness of the chip is large with respect to the area of the chip, which increases the physical and mechanical strength of the chip and causes the warpage and cracking. ease. Therefore, it is possible to grind more thinly than the back surface grinding in the wafer state. Further, since only the step of attaching the fixing tape to the element circuit formation surface of the wafer is added to the conventional step, the semiconductor device can be manufactured without increasing the man-hours.

[0019]

[Embodiment 4] In this embodiment, a part of the process sequence of Embodiment 3 is modified. FIG. 6 is a flowchart showing the process flow. After undergoing the wafer completion inspection, the semiconductor wafer 1 that has completed the element circuit forming process is fixed to a carrier jig and, for example, is diced into individual chips as shown in FIG. After dicing, the element circuit forming surface of each chip 1b is attached and fixed to the fixing member 3, and the back surface of each chip is ground to an arbitrary thickness using the grinder 2. The position of each chip maintains the positional relationship in the semiconductor wafer 1 before being diced.
By dividing the semiconductor wafer into individual chips and grinding the back surface in this manner, the ratio of the thickness of the chip to the area of one chip is larger than the ratio of the thickness to the area of the wafer. Strength increases, and the factors of warping and cracking are mitigated. Therefore, it is possible to grind more thinly than grinding in the wafer state. The individual chips 1b whose backside grinding has been completed are then fixed from the backside of the wafer by a fixing member, and wafer testing is performed to measure the electrical characteristics of the individual chips using a tester and a prober. After the completion of the wafer testing, the individual chips are sealed and cut and molded through an assembling process such as a die bonding process and a wire bonding process to complete a semiconductor device.

According to this embodiment, by dicing the semiconductor wafer before grinding the back surface of the semiconductor wafer, the thickness of the divided individual chips is larger than the ratio of the thickness to the area of the wafer. Because it gets bigger,
Increased mechanical and physical strength. Therefore, even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength. In addition, since wafer testing is performed after the back surface is ground, it is possible to measure the electrical characteristics of the chip state which is the closest to the final product.

The effects of the present invention will be described below.

(1) Before the back surface of the semiconductor wafer is ground, by dividing the semiconductor wafer into a plurality of pieces, the thickness of the divided individual wafers increases, so that the mechanical and physical strength increases. To do. Therefore, even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength.

(2) By dividing the semiconductor wafer into individual chips and then grinding the back surface, the thickness of the chip is large relative to the area of the chip, so that the physical and mechanical strength of the chip is increased and the factor of cracking is mitigated. Therefore, the semiconductor wafer can be ground even thinner than the back surface grinding.

(3) By providing a wafer testing step after the back surface of the semiconductor wafer is ground, the electrical characteristics of the wafer in the state closest to the final product can be measured.

(4) By dividing the semiconductor wafer into a plurality of pieces before grinding the back surface of the semiconductor wafer, the back surface of the semiconductor wafer can be thinly ground while maintaining its mechanical and physical strength. It can be made thinner.

The invention made by the inventor of the present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. In the above-mentioned embodiment, when the back surface was ground, the fixing member was attached to the element circuit forming surface, but this fixing member is a colorless transparent plate-shaped member having an adhesive applied to one surface, for example, a glass-based member, or An acrylic plate member is preferable from the viewpoints of stability during back surface grinding, control of adhesive strength using ultraviolet rays, recyclability, and the like. If the shape and size of the fixing member are, for example, the same as that of the semiconductor wafer before division, the same back grinding method as in the conventional method can be used. The same fixing member may be used during wafer testing after backside grinding. In that case, after the back surface is ground, the same fixing member is attached to the rear surface side while the fixing member is still attached to the element circuit forming surface, and then the element circuit forming surface is irradiated with ultraviolet rays from the element circuit forming surface side. Only the fixing member attached to can be peeled off. Since the element circuit formation surface is attached to the fixing member, it is desirable that the element circuit formation surface be flattened with a protective film or the like from the viewpoint of adhesion, uniformity of back surface grinding, and the like.

[0027]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, by dividing the semiconductor wafer into a plurality of pieces before grinding the back surface of the semiconductor wafer, the thickness of the divided individual wafers becomes large, so that the mechanical and physical strengths increase. . Therefore, even if the diameter of the semiconductor wafer is increased, the back surface can be thinly ground while maintaining its mechanical and physical strength.

[0029]

[Brief description of drawings]

FIG. 1 is a diagram showing a back surface grinding method for a semiconductor wafer according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a manufacturing flow of a semiconductor device using the method of FIG.

3 is a diagram showing another example of a manufacturing flow of a semiconductor device using the method of FIG.

FIG. 4 is a diagram showing a back surface grinding method for a semiconductor chip according to another embodiment of the present invention.

5 is a diagram showing an example of a manufacturing flow of a semiconductor device using the method of FIG.

6 is a diagram showing another example of a manufacturing flow of a semiconductor device using the method of FIG.

FIG. 7 is a diagram showing a conventional semiconductor wafer backside grinding method.

FIG. 8 is a diagram showing a manufacturing flow of a semiconductor device using a conventional semiconductor wafer back surface grinding method.

[Explanation of symbols]

1 ... Semiconductor wafer, 1a ... Divided wafer, 1b ... Chip, 2 ... Grinder, 3 ... Fixing member, 4 ... Semiconductor wafer, 5 ... Grinder, 6 ... Fixing member

Claims (6)

[Claims] 1. A method of manufacturing a semiconductor device in which individual chips are mounted in a semiconductor package after grinding the back surface of a semiconductor wafer that has completed an element circuit forming step, and before grinding the back surface of the semiconductor wafer. A method of manufacturing a semiconductor device, comprising a step of dividing the semiconductor wafer into a plurality of pieces. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the back surface of the semiconductor wafer is ground after being divided into four or more parts. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor wafer is divided into individual chips in a dicing step and then ground on the back surface. 4. The semiconductor wafer is divided into a plurality of pieces, and a colorless and transparent plate-like fixing member is attached to the element circuit formation surface of the semiconductor wafer, and the back surface is ground. A method of manufacturing a semiconductor device according to claim 1. 5. The method of manufacturing a semiconductor device according to claim 4, wherein the fixing member has the same shape as the semiconductor wafer. 6. The method of manufacturing a semiconductor device according to claim 1, further comprising a wafer testing step after the back surface of the semiconductor wafer is ground.