JP2007048995A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device whose film peeling in formation of a film peeling preventing film is less and the number of non-defective products is larger in a dicing process than before. <P>SOLUTION: A semiconductor element is formed in a semiconductor wafer 1, and a film peeling preventing groove is formed by applying laser irradiation light with a space kept in both sides of dicing lines 2, 3. The semiconductor wafer 1 is divided into a plurality of semiconductor chips by carrying out dicing along dicing lines 2, 3. At least a part of laser irradiation light is dispersion light which carries out laser irradiation intermittently. Since laser irradiation is little and influence of heat is reduced, dicing treatment of less film peeling and more non-defective products than before is carried out when a film peeling prevention film is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device capable of preventing peeling of a coating film constituting a semiconductor element formed on a semiconductor wafer in a dicing process.

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device, a semiconductor wafer is processed to form a semiconductor element, and is divided along a dicing line after processing to divide the semiconductor wafer into a plurality of semiconductor chips. However, the film formation on the main surface on which the semiconductor element is formed during dicing may peel off from the portion near the dicing line, resulting in a defective product. In order to reduce such defective products, it has been proposed to form film peeling prevention films on both sides of the dicing line. This film peeling prevention film is formed by laser irradiation light.
Conventionally, a laser is continuously applied to a semiconductor wafer and cut to form a film peeling prevention film. In this laser irradiation process, when the semiconductor wafer after laser irradiation is observed, peeling frequently occurs at the intersection of the irradiation light and the irradiation light. In particular, after blade dicing after irradiation, peeling occurs with considerable probability.

There exists patent document 1 in the prior art which concerns on dicing. In this case, a wiring layer is provided along the dicing line on the surface layer of the laser dicing area, and functions as a dummy pattern at the time of laser irradiation. The wiring layer as a dummy pattern absorbs laser light and makes the irradiation energy uniform to improve the dicing cutting property.
Japanese Patent Laid-Open No. 2004-221286

  The present invention provides a method for manufacturing a semiconductor device in which, in the dicing process, when a film peeling prevention film is formed, the film peeling is smaller than that in the prior art and the number of good products is higher.

  One aspect of the method for manufacturing a semiconductor device of the present invention includes a step of forming a semiconductor element on a semiconductor wafer, a step of forming a dicing line on the semiconductor wafer, and a gap on both sides of the dicing line in the semiconductor wafer. A step of forming a film peeling prevention groove by applying a laser irradiation light and a step of dicing the semiconductor wafer along a dicing line and dividing the semiconductor wafer into a plurality of semiconductor chips, wherein the laser irradiation light is at least partially Is characterized by discrete light that is intermittently irradiated with laser.

  In the present invention, since the influence of heat is reduced, when forming a film peeling prevention film, the film peeling is less than the conventional dicing process with many good products.

The present invention is characterized in that discrete light is laser-irradiated at intervals on both sides of a dicing line on a semiconductor wafer before a blade dicing step performed when dividing into semiconductor chips.
Hereinafter, embodiments of the invention will be described with reference to examples.

First, Embodiment 1 will be described with reference to FIGS.
1 is a plan view of a semiconductor wafer on which a blade dicing line is formed and laser dicing is performed, and FIG. 2 is a cross-sectional view of a semiconductor chip B cut out from the semiconductor wafer of FIG. 1 along the blade dicing line. 3 is a partial plan view showing a region A of the semiconductor wafer of FIG. In a semiconductor device, semiconductor elements are formed on a semiconductor wafer, and then the semiconductor wafer is diced along dicing lines to obtain a plurality of semiconductor chips on which the semiconductor elements are formed. Thereafter, the semiconductor chip is assembled and processed to obtain a product.

  FIG. 1 shows a semiconductor wafer 1 such as silicon. In this figure, a coordinate axis (XY) perpendicular to the wafer plane is attached for convenience. The horizontal direction is the X axis, and the vertical direction is the Y axis. The diameter of the semiconductor wafer is 6 inches to 8 inches, and a nodge or orientation flat may be provided in order to give directionality. A semiconductor element (not shown) is formed in the surface region of the semiconductor wafer 1 for each chip formation region. The chip forming area 6 is partitioned by blade dicing lines 2 and 3. The blade dicing line is formed by a blade, the blade dicing line 2 is formed in the X-axis direction (lateral direction), and the blade dicing line 3 is formed in the Y-axis direction (vertical direction).

Laser dicing 4 and 5 is performed along both sides of the blade dicing lines 2 and 3. The blade dicing line is a dividing line for dividing the semiconductor wafer into semiconductor chips, and a film peeling prevention groove is formed along the periphery of the semiconductor chip by laser dicing. The film peeling prevention grooves are formed on both sides of the blade dicing line in order to reduce the possibility of film formation on the main surface on which the semiconductor element is formed during dicing being peeled off from a portion close to the dicing line and resulting in a defective product.
FIG. 2 is a cross-sectional view of the semiconductor chip B cut out from the semiconductor wafer of FIG. 1 along the blade dicing line. A semiconductor chip divided from a semiconductor wafer such as silicon has an element region 12 formed in the surface region of the main surface of the semiconductor substrate 10, and a film formation 11 such as an interlayer insulating film and a protective film is performed on the surface of the semiconductor substrate 10. Has been. A film peeling prevention groove 13 is formed along each side of the semiconductor substrate 10. The film peeling prevention groove 13 is formed by laser dicing 4 and 5.

FIG. 3 is a partial plan view showing a region A of the main surface of the semiconductor wafer 1. Laser dicing 4 and 5 is performed along both sides of the blade dicing lines 2 and 3. The laser dicing 4 and 5 form a film peeling prevention groove 13 in the vicinity of the peripheral edge of the silicon semiconductor substrate 10 constituting the semiconductor chip under the film formation 11.
The semiconductor wafer 1 is divided along the blade dicing lines 2 and 3, and thus the semiconductor chip is formed in a region surrounded by the blade dicing lines 2 and 3. Therefore, the lines formed by the laser dicing 4 and 5 performed along both sides of the blade dicing lines 2 and 3 are formed on the periphery of the semiconductor chip, and an intersection is formed in the vicinity of the corner. In the conventional continuous laser beam, there are two laser irradiations at this intersection, which is a major cause of chipping at this portion.

  In this embodiment, in order to avoid twice irradiation to the intersection, discrete light is used as laser irradiation light for laser dicing in either the vertical direction or the horizontal direction, and continuous light is used for the other. In FIG. 3, continuous light is used for the laser dicing 5 in the vertical direction, and discrete light that is not irradiated to the intersection is used for the laser dicing 4 in the horizontal direction. Of course, other methods can be used to perform laser irradiation once at the intersection. For example, the laser dicing 5 in the vertical direction may alternately use dicing only with discrete light and the dicing with only continuous light, and the laser dicing 4 in the horizontal direction may use all discrete light. In this case, the laser dicing 4 is irradiated at the intersection point, and the irradiation is always performed once at any intersection point. In some cases, the horizontal laser dicing 4 uses alternating discrete light only dicing and continuous light only dicing, and the vertical laser dicing 5 uses all discrete light. In this case, irradiation is performed at the intersection point, and irradiation is always performed once at any intersection point. Furthermore, dicing is performed using only continuous light for every other part instead of alternately, and the other is subjected to dicing with discrete light so as to correspond to this, so that irradiation is always performed once at any intersection. .

The laser used in this example is YAG-THG (wavelength 355 nm), the Qsw frequency is 100 kHz, the average power is about 1.0 W, the melt diameter is about 30 μm, and the cutting speed is 100 mm / sec. . In this embodiment, in the YAG-THG laser, the Qsw frequency is suitably about 100 to 200 kHz, the average output is suitably about 1.0 to 10 W, and the melt diameter is suitably about 20 to 50 μm. The cutting speed is suitably about 80 to 400 mm / sec.
In this embodiment, the laser dicing intersection can always be irradiated once, so that the influence of heat is reduced, and when forming the film peeling prevention film, the film peeling is less and the number of non-defective products is larger than before. Is called.

Next, Embodiment 2 will be described with reference to FIG.
This embodiment is characterized in that two laser irradiation lights are not irradiated to the intersection at the intersection where the laser irradiation light intersects. FIG. 4 is a partial plan view (see FIG. 1) of a region including a semiconductor chip cut out from a semiconductor wafer.
FIG. 4 is a partial plan view showing the main surface of the semiconductor wafer 21. Laser dicing 24 and 25 is performed along both sides of the blade dicing lines 22 and 23. The laser dicing 24 and 25 form a film peeling prevention groove in the vicinity of the peripheral edge portion of the silicon semiconductor substrate constituting the semiconductor chip under film formation.
The semiconductor wafer 21 is divided along the blade dicing lines 22 and 23. Therefore, the semiconductor chip is formed in a region surrounded by the blade dicing lines 22 and 23. Therefore, the lines formed by the laser dicing 24 and 25 performed along both sides of the blade dicing lines 22 and 23 are formed on the periphery of the semiconductor chip, and an intersection is formed in the vicinity of the corner.

In this embodiment, discrete light is used as laser irradiation light for both vertical and horizontal laser dicing in order to avoid twice irradiation at the intersection. Here, no laser irradiation is performed on any intersection of laser dicing.
The laser used in this example is YAG-THG (wavelength 355 nm), the Qsw frequency is 100 kHz, the average power is about 1.0 W, the melt diameter is about 30 μm, and the cutting speed is 100 mm / sec. .
In this embodiment, the laser dicing intersection can always be irradiated once, so that the influence of heat is reduced, and when forming the film peeling prevention film, the film peeling is less and the number of non-defective products is larger than before. Is called. The influence of heat is less than in Example 1.

Next, Example 2 will be described with reference to FIG.
This embodiment is characterized in that both vertical and horizontal laser irradiation light is discrete light. FIG. 5 is a partial plan view (see FIG. 1) of a region including a semiconductor chip cut out from a semiconductor wafer.
FIG. 5 is a partial plan view showing the main surface of the semiconductor wafer 31. Laser dicing 34 and 35 is performed along both sides of the blade dicing lines 32 and 33. The laser dicing 34 and 35 forms a film peeling prevention groove in the vicinity of the peripheral edge of the silicon semiconductor substrate constituting the semiconductor chip under film formation.
The semiconductor wafer 31 is divided along the blade dicing lines 32 and 33, so that the semiconductor chip is formed in a region surrounded by the blade dicing lines 32 and 33. Lines formed by laser dicing 34 and 35 performed along both sides of the blade dicing lines 32 and 33 are formed at the periphery of the semiconductor chip, and an intersection is formed in the vicinity of the corner.

In this embodiment, as the laser irradiation light, discrete light that is irradiated at a predetermined interval is used as shown in the figure. In this embodiment, there is no contrivance to provide the irradiated portion at the intersection of the two laser irradiation lights. Therefore, there may be a case of one irradiation, two irradiations or no irradiation at this intersection.
The laser used in this example is YAG-THG (wavelength 355 nm), the Qsw frequency is 100 kHz, the average power is about 1.0 W, the melt diameter is about 30 μm, and the cutting speed is 100 mm / sec. .
In this embodiment, the laser dicing intersection may be irradiated twice, but it may not be irradiated at other portions, so that the influence of heat is reduced as a whole, and a film peeling prevention film is formed. In addition, a dicing process is performed in which the film is less peeled off and the number of non-defective products is higher than that of the prior art.

Next, Embodiment 4 will be described with reference to FIGS.
This embodiment is characterized by the irradiation method of the laser irradiation apparatus. FIG. 6 is a cross-sectional view of a semiconductor wafer on which a laser irradiation apparatus is arranged, FIG. 7 is a partial plan view of the semiconductor wafer on which a laser dicing line showing laser irradiation traces is formed, and FIG. 8 is a blade dicing line 2 is a partial cross-sectional view of a semiconductor wafer showing laser dicing performed along both sides of the line. The irradiation method of this embodiment can be applied to all of Embodiments 1 to 3.

  Laser dicing is performed on both sides of the semiconductor wafer 41 along the blade dicing line 43 before the blade dicing process performed when the semiconductor wafer 41 is divided into semiconductor chips. At this time, as shown in FIG. 6, when the laser irradiation device 40 is tilted, the energy density irradiated at the irradiation location is different. As shown in FIG. 7, the inclined area (right side in the figure) has a large irradiation area, but the opposite side to the inclined side (left side in the figure) has a small irradiation area. Therefore, a large amount of debris is generated on the inclined side, and the occurrence of debris on the side opposite to the inclined side is extremely small. As shown in FIG. 8, the width d on the left side of the center of the laser dicing line 45 is smaller than the width D on the right side (d <D). That is, since the side opposite to the inclined side of the laser irradiation device 40 can be cut vertically, the width of the laser dicing line 45 can be reduced. The width D on the right side of the laser dicing line 45 is large, and this portion has a large amount of debris. This portion is the side where the blade dicing line 43 is present, and the end of the chip when divided into semiconductor chips. Therefore, even if a large amount of debris is generated, there is little influence on the characteristics as a chip.

Similarly, the laser irradiation apparatus 40 shown in FIG. 6 is tilted in order to suppress the occurrence of debris in the laser dicing line 45 ′ on the right side of the blade dicing line 43. The direction of tilting is opposite to the direction shown in FIG. In this way, the width on the left side of the center of the laser dicing line 45 'becomes wider. Although this portion has a large amount of debris generated, this portion corresponds to the end of the chip when divided into semiconductor chips. Therefore, even if a large amount of debris is generated, there is no actual damage as a chip. The width on the right side of the center of the laser dicing line 45 'is narrow and the occurrence of debris is small.
The laser irradiation apparatus used in this example is YAG-THG (wavelength 355 nm), the Qsw frequency is 100 kHz, the average output is about 2.0 W, the melt diameter is about 30 μm, the cutting speed is 400 mm / sec, and the inclination is The angle θ is 45 degrees. This inclination angle is effective in the range of 5 to 85 degrees.
In this embodiment, since discrete light is used for laser dicing, the influence of heat is reduced as a whole, and when forming a film peeling prevention film, a dicing process is performed with less film peeling and more non-defective products.

  Further, in this embodiment, the laser irradiation light irradiated on both sides of the blade dicing line is irradiated while moving the laser irradiation device in the extending direction of the blade dicing line, and the laser irradiation device has the blade dicing line formed. Irradiation is performed while tilting to the side opposite to the side where the laser is present, so that the laser dicing line width can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a semiconductor wafer on which a blade dicing line according to a first embodiment which is an embodiment of the present invention is formed and laser dicing is performed. Sectional drawing of the chip | tip B cut out from the semiconductor wafer of FIG. The enlarged partial top view of A area | region of FIG. The fragmentary top view of the semiconductor wafer in which the blade dicing line based on Example 2 which is one Example of this invention was formed, and the laser dicing was performed. The fragmentary top view of the semiconductor wafer in which the blade dicing line based on Example 3 which is one Example of this invention was formed, and the laser dicing was performed. Sectional drawing of the semiconductor wafer with which the laser irradiation apparatus which concerns on Example 4 which is one Example of this invention is arrange | positioned. FIG. 7 is a partial plan view of the semiconductor wafer of FIG. 6 in which a laser dicing line showing laser irradiation traces is formed. FIG. 7 is a partial cross-sectional view of the semiconductor wafer according to FIG. 6 illustrating a blade dicing line and laser dicing performed along both sides of the line.

Explanation of symbols

1, 21, 31, 41 ... Semiconductor wafer 2, 3, 22, 23, 32, 33, 43 ... Blade dicing line 4, 5, 24, 25, 34, 35 ... Laser dicing line 6. ..Chip formation region 10... Semiconductor substrate 11... Film formation 12... Device region 13 .. Film peeling prevention film 40 .. Laser irradiation device 45, 45 '.. Laser dicing line

Claims (5)

Forming a semiconductor element on a semiconductor wafer;
Applying laser irradiation light at intervals on both sides of the dicing line of the semiconductor wafer to form a film peeling prevention groove;
A step of dicing the semiconductor wafer along a dicing line and dividing it into a plurality of semiconductor chips,
The method of manufacturing a semiconductor device, wherein the laser irradiation light is discrete light that at least partly performs laser irradiation intermittently. A plurality of the dicing lines are formed in the semiconductor wafer in the vertical direction and in the horizontal direction perpendicular to the direction, and the laser irradiation light irradiated on both sides of the dicing line is formed by the laser irradiation. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the laser irradiation is performed once or no laser irradiation is performed at the intersection of the two. The laser irradiation light applied to both sides of the dicing line irradiates continuous light in one of the vertical direction and the horizontal direction, and irradiates discrete light on the other. Semiconductor device manufacturing method. The laser irradiation light irradiated on both sides of the dicing line is irradiated while moving the laser irradiation device in the extending direction of the dicing line, and the laser irradiation device is opposite to the side on which the dicing line is formed. The method of manufacturing a semiconductor device according to claim 1, wherein the irradiation is performed while tilting the substrate. The method of manufacturing a semiconductor device according to claim 4, wherein an inclination angle of the laser irradiation apparatus is between 5 degrees and 85 degrees with respect to a vertical direction.

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