JPH0963993A - Semiconductor wafer dicing method, dicing apparatus, diode pellet manufacturing method, and diode pellet - Google Patents

Abstract

(57) [Summary] [Objective] To improve work efficiency in the process of assembling a semiconductor device, reduce damage to the semiconductor device during dicing, and improve utilization efficiency of a semiconductor wafer. [Structure] A doped portion 13 and an electrode portion 14 are arranged on the epitaxial layer 12 laminated on the element formation surface 10A side of the substrate 11 so as to be arranged in a lattice pattern at a predetermined pitch.
To the semiconductor wafer 10 in which the diode element having the structure in which the insulating layer 15 and the scribe line region 17 having a predetermined width are arranged around the doped portion 13 and the electrode portion 14 is formed, the scribe line of the element formation surface 10A is formed. Area 17
The diode pellet D is cut out by performing dicing with the dicing blade 51 from the side of the wafer back surface 10B so as to correspond to. The diode pellet D is
It has a substantially truncated pyramid shape with the element formation surface 10A side as the bottom and the wafer back surface 10B side as the top.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer dicing technique and a diode pellet manufacturing technique, and more particularly to a technique effective when applied to the production of fine size diode pellets.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a semiconductor device, a plurality of semiconductor elements collectively formed on a semiconductor wafer by a wafer process have been individually separated by dicing. In the wafer process,
By repeating thin film formation, etching, etc., semiconductor elements are formed in regions arranged in a grid on the element formation surface, which is one main surface of the semiconductor wafer, and in dicing, the boundary parts (scribe lines) of the respective areas are formed. The semiconductor elements are individually cut and separated by moving a dicing tool such as a blade along the semiconductor chip, but in order to identify the alignment marks and scribe lines on the surface of the semiconductor wafer for positioning the dicing tool, the semiconductor Dicing from the surface of the wafer was commonly used.

The semiconductor wafer dicing technology is described in, for example, the Nikkan Kogyo Shimbun, published on November 30, 1994, "Semiconductor Manufacturing Equipment Term Dictionary" P244, edited by the Japan Semiconductor Manufacturing Equipment Association. There is.

[0004]

However, in the dicing from the front surface side of the semiconductor wafer as in the above-mentioned conventional technique, for example, the following technical problems are encountered in the process of manufacturing a semiconductor element such as a diode pellet. It has been found.

That is, when a diode is manufactured from a semiconductor wafer, an element structure serving as an anode or a cathode is formed in a region arranged in a grid on the device formation surface side of the semiconductor wafer, and the element structure is cut along the region boundary. The part corresponding to the back surface side of the wafer (diode pellet) to be used is used as the cathode or anode of the opposite pole,
When manufacturing a fine diode pellet whose device dimensions in the plane of the semiconductor wafer are the same as the thickness dimension of the semiconductor wafer, the pellet becomes a dice shape, so the assembly process to connect the wiring structure to each anode and cathode, etc. In the above, the attitude of the diode pellet is not constant, so-called "pellet standing" occurs, and the work efficiency in the assembly process is reduced.

Further, in dicing from the surface side of the semiconductor wafer, there is a problem that the anode and the cathode having a small area are easily damaged by cracks at the time of cutting.

Further, in dicing from the surface side of the semiconductor wafer, it is necessary to increase the arrangement interval of the elements in consideration of the cutting allowance by the dicing blade, and the element size on the surface of the semiconductor wafer depends on the thickness of the semiconductor wafer. In the case of diode pellets of the same fine dimension, the cutting margin has a large effect on the reduction in the number of diode pellets that can be manufactured from one semiconductor wafer, and the utilization efficiency of the semiconductor wafer decreases. There is.

An object of the present invention is to provide a semiconductor wafer dicing technique capable of improving work efficiency in a semiconductor element assembling process.

Another object of the present invention is to provide a dicing technique for a semiconductor wafer which can reduce the damage of the semiconductor element during dicing and improve the yield.

Still another object of the present invention is to provide a semiconductor wafer dicing technique capable of increasing the number of semiconductor elements that can be manufactured from one semiconductor wafer.

Still another object of the present invention is to provide a diode pellet capable of improving work efficiency in the assembly process.

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.

[0013]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In the dicing technique of the present invention, dicing is performed from the back surface side of the wafer, which is the side opposite to the element formation surface, in the semiconductor wafer in which a plurality of semiconductor elements are collectively formed. As a dicing tool, for example, in the case of a dicing blade, the cross section of the outer peripheral portion for performing the cutting operation is substantially V-shaped or U-shaped.

Further, the present invention provides a dicing apparatus which has a mechanism for recognizing the cutting position of the semiconductor element forming region on the front surface side of the semiconductor wafer from the back surface side of the semiconductor wafer, and which performs dicing from the back surface side of the semiconductor wafer. .

Further, the diode pellet of the present invention has a substantially truncated pyramid shape in which the anode and the cathode are arranged at the top or the bottom.

[0017]

In the dicing technique of the present invention, since the dicing is performed from the back surface side of the semiconductor wafer, the cutting margin required at the boundary of each element formation region on the front surface of the semiconductor wafer is separated regardless of the width dimension of the dicing tool. You only have to set the interval to the extent of the cracking margin. Therefore, it is not necessary to consider the cutting margin according to the width dimension of the dicing tool, and the semiconductor elements can be densely arranged and formed on the element forming surface of the semiconductor wafer, and the semiconductor wafer can be manufactured from one semiconductor wafer. The number of semiconductor elements can be increased.

Further, since the influence of cracks or the like during dicing does not reach the element formation surface, damage to the element structure formed on the element formation surface of the semiconductor wafer is reduced, and the yield of semiconductor elements is improved.

Further, by making the shape of the dicing tool V-shaped or U-shaped, the cut-out semiconductor element has a truncated pyramid shape with the element formation surface side of the semiconductor wafer as the bottom and the wafer back surface side as the top. Thus, for example, in the case of a micro-sized diode pellet or the like, the posture of the diode pellet in the assembly process or the like becomes stable, and the occurrence of “pellet standing” or the like in which the posture becomes indefinite during assembly is reduced and the work efficiency is improved.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1, 2 and 3 are sectional views showing an example of a method for dicing a semiconductor wafer according to an embodiment of the present invention, FIG. 4 is a plan view thereof, and FIG. 5 is a view of the present invention. It is a perspective view showing an example of a dicing device of a semiconductor wafer which is one example.

First, the structure of the dicing apparatus of this embodiment will be described with reference to FIG. The semiconductor wafer 10 is mounted on the device forming surface 10A of the dicing stage 50 capable of two-dimensional translational movement and rotational displacement in the horizontal plane.
With the wafer facing downward, that is, the wafer back surface 10
It is placed in a posture with B facing upward.

A dicing blade 51 is vertically arranged above the dicing stage 50 while being supported by a rotating shaft 52. The rotary shaft 52 is mounted on a positioning mechanism (not shown), and enables the dicing blade 51 to move up and down and move horizontally.

In this case, in the vicinity of the dicing stage 50, the inspection light 5 is applied to the wafer back surface 10B of the semiconductor wafer 10.
A position recognition mechanism 55 including a light source 53 for irradiating 3a and a light receiving element 54 for detecting reflected light of the inspection light 53a from the wafer back surface 10B is arranged. And the inspection light 53
When a is, for example, ordinary visible light, the element formation surface 1
The unevenness of the wafer back surface 10B observed by reflecting the unevenness of the scribe line of 0A or the alignment mark on the wafer back surface 10B is image-recognized, and based on the recognition result, the semiconductor wafer 10 of the dicing blade 51 is detected.
Positioning control for the wafer back surface 10B is performed.

As the position recognition mechanism 55, a mechanism for observing an alignment mark (not shown) formed on the wafer back surface 10B of the semiconductor wafer 10 as necessary, or a mechanism for detecting the position of the end surface of the semiconductor wafer 10. Etc. can be used.

When the inspection light 53a is an infrared ray or the like that passes through the semiconductor wafer 10 made of, for example, silicon, the light receiving element 54 is an image of the scribe line and the alignment mark of the element forming surface 10A over the back surface 10B of the wafer. Is detected.

On the other hand, as illustrated in FIG. 1, the semiconductor wafer 10 of this embodiment has a substrate 11 made of, for example, a P ⁺ -type silicon single crystal, and a substrate 11 on the side of the element forming surface 10A. The epitaxial layer 12 is composed of stacked P ⁻ -type single crystal silicon. On the surface side of the epitaxial layer 12, the N ⁺ type doped portions 1 are arranged so as to be arranged in a lattice at a predetermined pitch.
3 is formed to form a P-N junction diode inside the epitaxial layer 12. Above the dope portion 13,
An electrode portion 14 made of, for example, aluminum is selectively formed to form a cathode. An insulating layer 15 made of, for example, silicon oxide is formed around the plurality of doped portions 13 and the electrode portions 14 arranged on the element formation surface 10A at a predetermined pitch. Around the insulating layer 15,
A scribe line area 17 having a predetermined width is arranged.

A conductor layer 16 made of, for example, gold (Au) is formed on the entire surface of the semiconductor wafer 10 on the wafer back surface 10B side and becomes an anode of the diode by dicing described later.

An example of the operation of the semiconductor wafer dicing method and apparatus of this embodiment will be described below.

First, the semiconductor wafer 10 is mounted and fixed on the dicing stage 50 so that the element forming surface 10A faces downward, that is, the wafer back surface 10B faces upward.

Next, the position recognizing mechanism 55 recognizes the position of the alignment mark and the scribe line area 17 on the element forming surface 10A side of the semiconductor wafer 10, and moves the dicing stage 50 horizontally relative to the dicing blade 51. Then, after performing a positioning operation by a rotational movement operation, etc., dicing is performed in a lattice pattern along the area corresponding to the scribe line area 17 on the element rear surface 10A side on the wafer back surface 10B, for example, by a full cut or semi-full cut method. To do.

At this time, when the cross section of the blade portion 51a on the outer periphery of the dicing blade 51 is V-shaped, as shown in FIG. 1, the wafer back surface 10B of the semiconductor wafer 10 faces the scribe line region 17. The width V gradually decreases
The diode pellet D is formed with a V-shaped cutting groove 10C.
Is formed.

Here, as in the conventional case, the element forming surface 10A
When the dicing is performed, the width WS of the scribe line region 17 needs to be larger than the thickness WB of the dicing blade 51 to prevent damage to the peripheral portion of the diode pellet D.

On the other hand, when dicing the back surface 10B of the wafer as in this embodiment, as is apparent from FIG. 1, the width of the scribe line region 17 is irrespective of the thickness WB of the dicing blade 51. WS can be reduced. That is, the element formation surface 1 of one semiconductor wafer 10
The number of diode pellets D that can be arrayed in 0A is
The number can be increased more than when dicing the element forming surface 10A.

The outer peripheral portion of the diode pellet D along the scribe line region 17 is the dicing blade 5
It is also possible to avoid the occurrence of cracks that cause product defects due to contact with the 1 and the like, and improve the yield of the diode pellets D.

Further, the external shape of the diode pellet D cut out as shown in FIG. 1 is a truncated pyramid shape having the wafer back surface 10B side as the top and the element formation surface 10A side as the bottom. The posture is stabilized so that the element forming surface 10A side faces downward. For this reason, for example, when the postures are aligned by applying a vibration or the like to a large number of diode pellets D in a later assembling step, all the diode pellets D are arranged on the element forming surface 10A.
Since the side with the arrow mark "" faces down, problems such as "pellet standing" in which the diode pellet D faces sideways do not occur, and the efficiency of the assembly work is greatly improved. Further, since the size of the wafer back surface 10B becomes small, it is advantageous for the occurrence of pellet cracks.

The shape of the cutting groove is not limited to the shape of the cutting groove 10C of FIG. 1, but as shown in FIG. 2, for example, the shape of the blade portion 51a of the dicing blade 51 is substantially V-shaped. By forming the tip portion to have a round shape, the bottom portion of the groove may have a loop shape like the cutting groove 10D having a round shape.

Alternatively, as illustrated in FIG. 3, a plurality of types of dicing blades 51 having different thicknesses with rounded tips of the blade portions 51a are used. After dicing, thick blade 5
It is also possible to form the multistage cutting groove 10E by two-step dicing by shallowly dicing with 1a.

Although the invention made by the present inventor has been specifically described based on the embodiments, the 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.

For example, the semiconductor element is not limited to the diode pellet but may be another semiconductor element.

[0041]

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

According to the method for dicing a semiconductor wafer of the present invention, it is possible to improve the working efficiency in the process of assembling a semiconductor device.

Further, according to the method for dicing a semiconductor wafer of the present invention, it is possible to reduce the damage to the semiconductor elements during dicing and improve the yield.

Further, according to the semiconductor wafer dicing method of the present invention, it is possible to increase the number of semiconductor elements that can be manufactured from one semiconductor wafer.

Further, according to the dicing apparatus for semiconductor wafers of the present invention, it is possible to improve the working efficiency in the process of assembling semiconductor elements.

Further, according to the dicing apparatus for semiconductor wafers of the present invention, it is possible to reduce the damage to the semiconductor elements during dicing and improve the yield.

Further, according to the semiconductor wafer dicing apparatus of the present invention, it is possible to increase the number of semiconductor elements that can be manufactured from one semiconductor wafer.

Further, there is an effect that the working efficiency in the diode pellet assembling process of the present invention can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a semiconductor wafer dicing method that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a semiconductor wafer dicing method that is an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an example of a semiconductor wafer dicing method that is an embodiment of the present invention.

FIG. 4 is a plan view showing an example of a semiconductor wafer on which a semiconductor wafer dicing method according to an embodiment of the present invention is implemented.

FIG. 5 is a perspective view showing an example of a semiconductor wafer dicing apparatus that is an embodiment of the present invention.

[Explanation of symbols]

 10 Semiconductor Wafer 10A Element Forming Surface 10B Wafer Backside 10C Cutting Groove 10D Cutting Groove 10E Cutting Groove 11 Substrate 12 Epitaxial Layer 13 Doped Part 14 Pole Part 15 Insulating Layer 16 Conductive Layer 17 Scribe Line Area 50 Dicing Stage 51 Dicing Blade 51a Blade Part 52 rotation axis 53 light source 53a inspection light 54 light receiving element 55 position recognition mechanism D diode pellet

Claims (8)

[Claims] 1. A method of dicing a semiconductor wafer, wherein dicing is performed from the back surface side of the wafer opposite to the element formation surface in a semiconductor wafer in which a plurality of semiconductor elements are collectively formed. 2. The method of dicing a semiconductor wafer according to claim 1, wherein the dicing forms a multi-step dicing groove having a substantially V-shaped or U-shaped cross-section or a stepwise change in width dimension on the back surface of the wafer by the dicing. A method for dicing a semiconductor wafer, comprising: 3. The semiconductor wafer dicing method according to claim 1, wherein the semiconductor wafer has an anode or a cathode arranged on the element formation surface side and a cathode or an anode arranged on the wafer back surface side. A method for dicing a semiconductor wafer, which comprises: 4. A dicing stage in which a semiconductor wafer is mounted in a posture in which a wafer rear surface side opposite to an element formation surface thereof faces upward, and a dicing tool for performing a dicing operation by contacting the wafer rear surface side. And a position recognizing unit that recognizes a dicing position of the semiconductor wafer in a posture with the back surface of the wafer facing upward and controls a dicing position of the dicing tool with respect to the semiconductor wafer. . 5. The dicing apparatus for a semiconductor wafer according to claim 4, wherein the dicing tool comprises a rotating dicing blade, and an outer peripheral portion of the dicing blade has a substantially V-shaped or U-shaped cross-section. The dicing device for a semiconductor wafer, wherein the dicing groove formed on the back surface of the wafer has a substantially V shape, a substantially U shape, or a multi-step shape whose width dimension changes stepwise. 6. A semiconductor in which a plurality of diodes are collectively formed such that an anode or a cathode is arranged on the element formation surface side and a cathode or an anode is arranged on the back surface of the wafer opposite to the element formation surface. A method of manufacturing a diode pellet, wherein the diode is individually cut out from a wafer by dicing to obtain a diode pellet, wherein an outer dimension of the anode or cathode side on the element formation surface side is a cathode or an anode side on the wafer back surface side. A method of manufacturing a diode pellet, which is characterized in that the size is larger than the external dimensions of the. 7. The method of manufacturing a diode pellet according to claim 6, wherein each of the diode pellets has the anode or cathode side on the element formation surface side as a bottom portion and the cathode or anode side on the wafer back surface side as a top portion. A method of manufacturing a diode pellet, characterized by exhibiting a substantially truncated pyramid. 8. The anode or cathode side is the bottom,
A diode pellet having a substantially truncated pyramid shape having a top on the cathode or anode side.