KR20010073297A - Calibration apparatus for wafer marking system - Google Patents

Abstract

PURPOSE: An apparatus for correcting a wafer marking system is provided to make possible the correcting for the whole region that is markable by using the correcting plate of the same diameter as a circular wafer so as to correct the path of a laser beam. CONSTITUTION: A correcting plate is set in the position of a wafer(22), and the laser beam from a laser assembly(28) is inputted in a hole by using an x-axis scanner(24) and a y-axis scanner(26). The laser beam is detected in an optical sensor, and the detected signal is stored in a computer(30) as a position correcting value. By using this method, the position correcting value detected in all holes is stored in the computer(30) as data. Then, the correcting plate of circular type(32) guides the laser beam to irradiate in the inside of the wafer(22), and makes the laser beam reach the die(22a) which is circuit-patterned in the wafer(22). After removing the correcting plate(34), the wafer is loaded in the inside of the chamber(20) and set, then the logo, which is inputted in the die(22a) of the position that is corrected in the computer(30), is marked.

Description

Calibration device for wafer marking system {CALIBRATION APPARATUS FOR WAFER MARKING SYSTEM}

The present invention relates to a wafer marking system, and more particularly, to calibrate a path of a laser beam prior to marking directly on the other surface of an opposing die on one side of which a circuit pattern is formed without cutting the die of the wafer. A calibration apparatus for a wafer marking system comprising a calibration apparatus used for the purpose.

In general, the process until the semiconductor die (chip) is completed is a wafer manufacturing process for making high purity single crystal silicon wafer from sand, designing an electronic circuit to be implemented on the wafer, and dividing the designed electronic circuit into layers in a glass mask. The process of drawing, the process of constructing electronic circuits by repeatedly cutting specific parts using masks made by forming various kinds of films on the surface of the wafer, and cutting the die on the wafer individually This is done through a package process of assembling the finished product in combination with the process and checking whether the finished product works properly.

Recently, as the size of various electric and electronic products has been miniaturized, studies have been developed to achieve a small size and high capacity by mounting a larger number of chips on a limited sized substrate.

The semiconductor package protects semiconductor chips such as single devices and integrated circuits formed by bonding various electronic circuits and wirings from various external environments such as dust, moisture, electrical and mechanical loads, and optimizes and maximizes the performance of semiconductor chips. It also refers to a resin encapsulation unit formed by forming an input / output terminal to a main board using a printed circuit board or a flexible circuit board and wrapping it with a sealing means.

In particular, in recent years, the development of the surface-mount semiconductor package, chip size semiconductor package that can reduce the volume of the semiconductor package close to the volume of the semiconductor chip, and also increase the mounting density on the motherboard by maximizing the number of input and output terminals A chip size package (CSP) has been developed to help thin and short and high functionality semiconductor packages.

In accordance with this, specific symbols, numbers, and letters are marked on the top or the back of the conventional semiconductor package using ink or laser.

Before the marking is performed, as shown in FIG. 1, the die 4 of the wafer 2 is sawed, the dies 4 are all set in the tray 6, and the tray 6 is not shown. The laser beam irradiated from the laser assembly 8 is marked on the upper surface of the die 4 while being transferred to the apparatus.

As the laser beam passes through the lens and is distorted by the curvature of the lens, the laser beam is normally subjected to calibration of the laser beam, so that the marking of the wafer is accurately performed. Before marking, the grid coordinates must be identified by the controller, and the X and Y axis scanners of the laser assembly are adjusted by commands provided by the controller to correct the path of laser beam movement.

At this time, a calibration plate is used, which is used to set the grid coordinates in connection with the controller. A lattice-shaped hole is formed on the surface of the square calibration plate, and an optical sensor is built into the inside corresponding to the hole.

This operation first places the square calibration plate on the marking surface on the tray and moves the laser beam to enter the square calibration plate. The beam then enters all holes in the calibration plate and stores all of its coordinates in the controller.

Then, the correction values are calculated in advance for the entire area to be marked using the stored coordinates and stored again.

When the marking operation is performed later, the stored correction values may be reflected.

However, when the semiconductor chip is mounted on the tray and transferred by the laser, the rectangular calibration plate used in the above-described conventional marking operation has no problem, but the marking on the circular wafer is performed immediately without cutting the die of the wafer. In this case, a rectangular calibration plate having a size including the size of a circular wafer should be manufactured. This rectangular calibration plate is optically corrected because the laser beam is not focused on the corners formed at four vertices from the edge of the wafer. The process is not performed.

SUMMARY OF THE INVENTION The present invention devised to solve the above problems is an object of the present invention to provide a calibration apparatus used to calibrate the path of a laser beam in order to perform a marking operation without sawing a die of a circular wafer.

In order to achieve the above object, the calibration apparatus for a wafer marking system of the present invention includes a housing chamber in which a wafer is fixed therein; A laser assembly for firing a laser beam toward the wafer to be marked on the die of the wafer; A scanner installed in the path of the laser beam to adjust a position at which the laser beam reaches the wafer; It is formed of a disk corresponding to the maximum size of the wafer and includes a case in which holes are formed at regular intervals in a lattice shape on the surface thereof, and a plurality of optical sensors installed in the case in correspondence with the holes and marked on the wafer. A calibration plate temporarily set at that position where the wafer is to be set before this is done; And the laser beam, which is connected to the laser assembly, scanner and calibration plate at the same time, stores the position value of the laser beam which is incident to the hole and sensed by the optical sensor. It comprises a control means to.

Here, it is preferable that the area of arrival of the laser beam is made within the range of the calibration plate.

1 is a view schematically showing a wafer marking step using a conventional laser assembly,

2 is a perspective view schematically showing the structure of a wafer marking system according to an embodiment of the present invention;

3 is a plan view showing a calibration plate according to the present invention;

4 is a sectional view showing a part of a calibration plate according to the present invention;

*** Explanation of symbols for the main parts of the drawing ***

20: chamber 22: wafer

22a: wafer die 24: X-axis scanner

26: Y axis scanner 28: laser assembly

30: Computer 32: Calibration Edition

34: Case 36: Hall

38: Light sensor

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 is a perspective view schematically showing the structure of the wafer marking system of the present invention, FIG. 3 is a plan view showing a calibration plate according to the present invention, and FIG. 4 is a cross-sectional view showing a part of the calibration plate.

In the drawing, the dotted line indicates the chamber 20. A fixing means (not shown) for fixing the wafer 22 is provided inside the chamber 20, and a laser beam is directly below the chamber 20. The X-axis scanner 24 and the Y-axis scanner 26 which adjust the path | route of this are integrally provided. On one side, the laser assembly 28 is installed.

The X-axis scanner 24 and the Y-axis scanner 26 are connected to the computer 30 as a control means, respectively, and the computer 30 is connected to the calibration plate 32 proposed in accordance with the features of the present invention.

The calibration plate 32 is formed of a disk corresponding to the maximum size of the wafer 22. The calibration plate 32 corresponds to the case 34 and the hole 36 having holes 36 formed on the surface at regular intervals. It is composed of a plurality of optical sensors 38 installed in the case 34. The plurality of optical sensors 38 are installed on the circuit board 40 embedded in the case 34.

As the calibration plate 32 is temporarily connected to the computer 30 and used for calibration of the laser beam, the calibration region of the laser beam is made inside the calibration plate 32 and as a result is marked on the wafer 22. The possible area is determined by the calibration plate 32.

In addition, an interface 42 is installed between the calibration plate 32 and the computer 30 so that signals exchanged between the calibration plate 32 and the computer 30 are shared.

It looks at the operation and effects of the wafer marking system of the present invention configured as described above.

First, the calibration plate 32 is set precisely at the position where the wafer 22 is placed, and the laser beam irradiated from the laser assembly 28 is used for the hole (using the X-axis scanner 24 and the Y-axis scanner 26). Enter 36).

The incident laser beam is detected by the optical sensor 38, and the detected signal is stored in the computer 30 as a position correction value. Using this method, the position correction value detected in the entire hole 36 is stored as data in the computer 30, wherein the proposed circular calibration plate 32 according to the characteristics of the present invention is a laser beam wafer 22 The laser beam is directed to each of the dies 22a circuit-patterned on the wafer 22.

Subsequently, when the wafer 22 is loaded and positioned inside the chamber 20 after the calibration plate 34 is removed, the logo input to the die 22a corresponding to the position corrected by the computer 30 is displayed. Will be marked.

As described above, embodiments of the present invention substantially solve the conventional problems.

That is, the laser beam path is calibrated by using a calibration plate having the same diameter as that of the circular wafer in order to perform the marking operation without sawing the die of the circular wafer, thereby ultimately correcting the entire area where the wafer marking system can be marked. Can be.

Claims (2)

A housing chamber in which a wafer is fixed therein; A laser assembly for firing a laser beam toward the wafer to be marked on the die of the wafer; A scanner installed in a path of the laser beam to adjust a position at which the laser beam reaches the wafer; It is formed of a disk corresponding to the maximum size of the wafer and comprises a case in which holes are formed at regular intervals in a grid shape on the surface, and a plurality of optical sensors installed in the case corresponding to the hole, A calibration plate temporarily set at the position at which the wafer is set before marking is performed on the wafer; And The laser beam is connected to the laser assembly, the scanner and the calibration plate at the same time, and stores the position values of the laser beams incident to the holes and sensed by the optical sensor, and then adjusts the positions of the laser assembly and the scanner when marking the wafer. Calibrating apparatus for a wafer marking system, characterized in that it comprises a control means for making a marking of the form. The calibration apparatus for a wafer marking system according to claim 1, wherein the area of arrival of the laser beam is within a range of the calibration plate.