JP2001080297A - Method for producing letter diagram of transparent body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the letter diagram of a transparent body in which letters and a diagram are protected even in a state the surface of the transparent body is fouled, wetted, or somewhat damaged, and process control and product control can be surely performed. SOLUTION: In a method, radiation is done with the focus F of a laser beam 4 put in the inside of a transparent body passing through the surface a silicon wafer 1 which is the transparent body. An unit cell 3a of a bright pattern is formed by changing in quality by the heat of the laser beam 4, non-irradiated part is made a dark unit cell 3b, these unit cells 3a, 3b are combined to bake a two-dimensional code 2 by the matrix of a bright/dark pattern in the inside of the silicon wafer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a transparent character or graphic in which characters or figures are printed inside a transparent material such as glass, a silicon substrate, or plastic.

[0002]

2. Description of the Related Art In recent years, in a semiconductor manufacturing process, in a process of manufacturing a silicon wafer and a semiconductor chip having a circuit formed thereon, it has been demanded that these be individually managed in each process. Since silicon wafers are hard and transparent, identification data such as material type and serial number cannot be printed on the silicon wafer. Conventionally, product numbers and serial numbers have been directly baked with lasers in English letters and numbers. In addition, barcodes and two-dimensional codes are baked with lasers instead of these letters and numbers, and processes and products are being controlled.

The use of barcodes and two-dimensional codes for manufacturing processes and product management in fields such as glass products such as cathode ray tubes for televisions and window glasses for automobiles, and transparent plastic plates such as liquid crystal displays has also been studied. I have.

However, when characters, figures, bar codes, two-dimensional codes, and the like are formed on the surface of such a transparent body, there is a problem that the surface cannot be identified if the surface becomes dirty or wet. In addition, letters and code surfaces formed by roughening the surface by laser baking are easily scratched,
There was also a problem that reading became impossible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and protects characters and figures even when the surface of a transparent body is dirty, wet, or slightly damaged, and enables process management and product management. And a method for creating a transparent character / graphic figure capable of reliably performing the following.

[0006]

According to a first aspect of the present invention, there is provided a method for forming a character or graphic on a transparent body, the method comprising: irradiating a laser beam with a laser beam focused on a transparent body through a surface thereof; Characteristically, characters and figures are printed inside the transparent body by this heat.

According to a second aspect of the present invention, there is provided a character / figure forming method for a transparent body, wherein the wavelength of the laser beam is 0.3 to 1.1 μm.
m. According to a third aspect of the present invention, there is provided a transparent character / figure creation method, wherein a laser beam is irradiated at a convergence angle of 5 to 20 degrees.

According to a fourth aspect of the present invention, there is provided a method of forming a character figure on a transparent body, wherein the figure formed inside the transparent body is a two-dimensional code, and a portion irradiated with a laser beam is a unit cell having a light pattern, and the non-irradiation is performed. The two-dimensional code is formed by combining a light and dark unit cell with a portion as a dark pattern unit cell and combining these light and dark unit cells.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described in detail with reference to FIG. In the figure, 1 is a silicon wafer, which is a thin slice of a single-crystal silicon round bar, on which a circuit is formed,
The semiconductor chip is cut vertically and horizontally to form a large number of square semiconductor chips. FIG. 2 shows the inside of the silicon wafer 1.
The two-dimensional code 2 is formed as shown in FIG.

The two-dimensional code 2 is formed, for example, by dividing an area having a side width of 1.2 mm square into four rows and four columns of squares to form 16 square cells 3. It is formed in a square having a width of 240 μm on one side. This cell 3 has a bright unit cell 3a and a dark unit cell 3b,
These are combined vertically and horizontally according to the code data to form a two-dimensional code 2 using a matrix of light and dark patterns.

The method of creating the two-dimensional code 2 is to create image data using a matrix of light and dark patterns on a personal computer screen using image software, and create code data from the image data. Next, as shown in FIG. 1, the silicon wafer 1 is set in a laser printer, and a laser beam 4 oscillated from a laser oscillator is narrowed down by a lens 5 and transmitted through a transparent surface to irradiate the inside of the silicon wafer 1. In this case, the laser beam 4 is irradiated in such a manner that the focal point F of the laser beam 4 is adjusted to the code forming position on the silicon wafer 1.

In this case, the laser beam 4 to be used is
When the laser beam 4 is irradiated at a convergence angle α of 5 to 20 degrees, the crystal structure of the inside of the silicon wafer 1 is altered by the heat of the laser. It becomes opaque, and when light is applied to this portion by forming dots of the beam continuously or independently, it is irregularly reflected and becomes a bright unit cell 3a.
Note that a portion not irradiated with the laser beam 4 becomes a dark unit cell 3b because light is transmitted therethrough.

[0013] A bright unit cell 3a which is baked by irradiating a laser based on the code data created from the image data as described above, and a dark unit cell 3b which is not irradiated by the laser.
Can be formed vertically and horizontally to form a two-dimensional code 2 using a light and dark pattern matrix. By defining the wavelength of the laser beam 4 and the irradiation angle α in the above ranges, the depth of focus and the amount of heat can be controlled, and the laser beam 4 is converged at the internal focus without affecting the surface of the silicon wafer 1 by heat. The dimension code 2 can be printed.

If the wavelength of the laser beam 4 to be irradiated is shorter than 0.3 μm, the thin and transparent silicon wafer 1
Is difficult to focus inside the
At a long wavelength exceeding μm, the laser beam 4 is easily scattered and hardly reaches the inside. Laser beam 4
If the convergence angle α is less than 5 degrees, it is difficult to focus, and if the irradiation angle α is more than 20 degrees, it is difficult to scan the laser beam 4 over a wide range. This is because, in particular, when the light is irradiated obliquely, it spreads in an elliptical shape at the focal point portion F and clear printing cannot be performed.

When the two-dimensional code 2 formed inside the silicon wafer 1 is read by a light reflection type reader, when light is irradiated from the surface of the silicon wafer 1, the silicon wafer 1 is transparent and any processing is performed. Since the light 7 is transmitted without reflection as it is, the reading unit recognizes it as a dark unit cell 3b. In addition, the portion printed by irradiating the laser is irregularly reflected and is recognized as a bright unit cell 3a by the reader. Therefore, by combining these, the two-dimensional code 2 on which a light and dark pattern is printed can be read in the same manner. Conversely, when reading with a light transmission type reading device, the bright unit cell 3a and the dark unit cell 3b are read in reverse.

Since the two-dimensional code 2 is formed inside the silicon wafer 1, an insulating film or a circuit can be formed on the surface. Further, since the two-dimensional code 2 is formed inside the silicon wafer 1, even if the wafer surface is soiled or damaged, the internal two-dimensional code 2 is not affected, and the process control and the product control can be performed reliably. .

FIG. 3 shows another embodiment of the present invention, in which a bar code 6 is formed inside a silicon wafer 1. FIG. 4 shows a product number 7 formed by combining alphabets and numerals inside the silicon wafer 1.

In the above description, the case where the two-dimensional code 2, the bar code 6, the product number 7 and the like are formed inside the silicon wafer 1 has been described, but in addition to glass products such as a cathode ray tube of a television and a window glass of an automobile, It can be formed inside a transparent body such as a transparent plastic plate such as a liquid crystal display and used for manufacturing processes and product management.

[0019]

As described above, claim 1 according to the present invention.
According to the described method for creating a character figure of a transparent body, a laser beam is irradiated while focusing on the inside of the transparent body, and characters and figures are burned inside the transparent body by the heat of the beam. Circuits and the like can be formed in addition to films such as a conductive film, a fluorescent film, and a reflective film. Further, since the characters and figures are formed inside the transparent body, even if the surface becomes dirty or damaged, the inside characters and figures are not affected and the process control and the product control can be performed reliably.

According to a second aspect of the present invention, the wavelength of the laser beam is set to 0.3 to 1.1.
In the method according to the third aspect, by irradiating the laser beam with a convergence angle α of 5 to 20 degrees, the heat of the laser widely prints characters and figures inside the transparent body over a wide range. be able to.

According to a fourth aspect of the present invention, the figure formed inside the transparent body is a two-dimensional code, the portion irradiated with the laser beam is a bright unit cell, and the non-irradiated portion is formed. Is a dark unit cell, and these light and dark unit cells are combined to form a two-dimensional code with a light and dark pattern matrix, so that a large amount of data can be recorded inside the transparent body, and silicon wafers and small semiconductor chips can be individually Can be managed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a laser beam is irradiated inside a silicon wafer according to an embodiment of the present invention.

FIG. 2 is a plan view showing a state in which a two-dimensional code is formed inside the silicon wafer of FIG.

FIG. 3 is a plan view showing a state in which a barcode is formed inside a silicon wafer according to another embodiment of the present invention.

FIG. 4 is a plan view showing a state in which a product number is formed inside a silicon wafer according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 silicon wafer 2 two-dimensional code 3 cell 3a bright unit cell 3b dark unit cell 4 laser beam 5 lens 6 barcode 7 product number

Claims (4)

[Claims] 1. A transparent body characterized in that the laser beam is focused on the inside of the transparent body through the surface of the transparent body and irradiated with the laser beam, and the heat is used to print characters, figures and the like inside the transparent body. How to create a character figure. 2. A laser beam having a wavelength of 0.3 to 1.1.
2. The method according to claim 1, wherein the thickness is set to μm. 3. The method according to claim 1, wherein the laser beam is irradiated at a convergence angle of 5 to 20 degrees. 4. A figure formed inside the transparent body is a two-dimensional code, and the light-irradiated part is a light-pattern unit cell, and the non-irradiated part is a dark-pattern unit cell. 2. The method according to claim 1, further comprising forming a two-dimensional code using a light and dark pattern matrix.