JP2010245123A - Table with transmissive lighting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a table with transmissive lighting capable of positioning a substrate by transmissive lighting and machining the substrate by making a machining tool press against. <P>SOLUTION: The table including transmissive lighting includes: an infrared light source; a metal sub-table, where a movable mechanism is mounted to a lower portion and a table placement surface for placing a top table is formed at an upper portion; and the top table that includes a bottom face brought into face contact with the table placement surface of the sub-table, an upper surface for placing a substrate, and the incidence side surface for allowing infrared light of the infrared light source to enter, and is made of an infrared transmissive material. A reflection surface for reflecting the infrared light entering from the incidence side surface toward an upper surface is provided inside the top table, and at a lower portion of a position for placing the substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, an infrared light transmitting substrate such as a silicon substrate placed on a table is irradiated with infrared light from the substrate surface (referred to as the back surface) on the side in contact with the table so as to pass through the substrate. Thus, the present invention relates to a transmission illumination table that can detect a transmission image of an alignment mark formed on the back surface.

  Inspecting the covering state of the wiring layer formed on the semiconductor substrate, or measuring the positional deviation of the mark serving as the position reference of the front and back surfaces of the reticle (mask) used when forming the fine pattern of the semiconductor integrated circuit In this case, a transmitted illumination image by infrared light irradiated from the back surface side of the substrate and transmitted to the front surface side of the substrate is acquired, and the substrate is inspected or misaligned (see Patent Documents 1 and 2). ).

  For example, in Patent Document 1, a defective portion of a step coverage is detected after a wiring layer is formed on a semiconductor substrate. At that time, light including infrared light having a wavelength of 1.3 to 6 μm is irradiated from the back surface of the substrate. Thus, a method is disclosed in which light transmitted through the substrate is detected by an infrared detector, and the covering state of the wiring layer is inspected by the transmitted light. According to this document, the infrared light emitted from the lamp house is reflected by a mirror disposed below the substrate, and the reflected infrared light is emitted to the substrate to realize the transmitted illumination. In addition, this document does not disclose any specific structure regarding a method for supporting a substrate when performing transmission illumination.

Further, Patent Document 2 discloses a substrate front / back surface mark position measuring apparatus that can easily measure alignment errors between the front and back surfaces of a reticle when manufacturing a reticle using a silicon substrate.
According to this, illumination light of near-infrared light (wavelength 0.98 μm) is applied to the periphery of the mark from the front surface or back surface (first surface) of the silicon substrate, and the light transmitted through the substrate is transmitted to the other part of the substrate. Lead to the image acquisition device on the surface (second surface) side to obtain the image of the first mark on the first surface and the image of the second mark on the second surface, and combine the images of both marks In addition, the difference between the two positions is measured.
In this substrate front / back surface mark position measuring apparatus, a silicon substrate is placed on a reticle stage to support the substrate. Since the reticle stage is required to be robust, it is made of a material that does not transmit infrared light such as metal. For this reason, the reticle stage is provided with a hole for transmitting infrared light for transmitted illumination, and the first mark and the second mark for measuring the position of the silicon substrate are placed on this hole. Placed.

JP-A-1-109735 JP 2004-349544 A

When scribing or dividing a silicon substrate, the substrate is placed on a table (also referred to as a stage), and the substrate is positioned with respect to the table by an alignment mark formed in advance on the substrate. In addition, there is a case in which a processing tool such as a cutter wheel is used for processing along a desired processing line.
As described above, when the substrate positioning and substrate processing are continuously performed on the table, depending on the substrate to be processed, the substrate surface on the side where the alignment mark is formed is contacted with the table for convenience of the process. (Back side) may have to be.
In that case, it is necessary to perform positioning by irradiating the region where the alignment mark is formed from the back side by using the transmitted illumination described in the background art and detecting the transmitted image.

On the other hand, in scribing or cutting, the substrate is locally pressed with a certain pressing force using a processing tool. However, the position directly below the pressed position is not a metal table surface, but Patent Document 2 If the hole is for passing infrared light similar to the reticle stage disclosed in, the substrate may be bent and damaged by the pressing.
For this reason, it is difficult to perform positioning by transmitted illumination and substrate processing by pressing a processing tool on a single stage in a table (also referred to as a stage) in which holes for allowing infrared light to pass are formed. It was.

  Furthermore, when processing a substrate, to move or rotate the table on which the substrate is placed in a two-dimensional or three-dimensional direction, move the table moving mechanism or rotation mechanism to the bottom of the table. Therefore, it is impossible to freely design the installation location of the light source in the case of transmitting illumination and the irradiation optical system from the light source to the substrate.

  Therefore, the present invention can position the substrate by confirming the alignment mark with transmitted illumination in a state where the substrate surface on which the alignment mark is formed is in contact with the table surface, and press a processing tool such as a cutter wheel. An object of the present invention is to provide a table with transmitted illumination that can perform substrate processing.

  The table with transmitted illumination according to the present invention, which has been made to solve the above-mentioned problems, is a metal sub having an infrared light source, a movable mechanism attached to the lower part, and a table support surface supporting the top table formed on the upper part. A table, a bottom surface that is in contact with the table support surface of the sub-table, an upper surface on which the entire back surface of the substrate is placed in an in-contact state, and an incident side surface on which infrared light from an infrared light source is incident. A reflective surface that reflects infrared light incident from the incident side toward the upper surface is provided inside the top table and below the position where the substrate is placed. The infrared light passes through the infrared transmitting material constituting the top table and is irradiated onto the substrate.

Here, the reflection surface may be formed by the surface of a metal block fitted in a space formed by cutting out a part of the top table.
The reflection surface may be provided with an infrared light reflection film on an inclined surface formed by cutting out a part of the top table.
The reflective surface may be a reflective screen created by laser irradiation on a part of the top table.

  According to the table with transmitted illumination of the present invention, infrared light is incident from the incident side surface of the sub-table, and the upper surface is irradiated with infrared light by the reflecting surface. Thereby, the infrared light which permeate | transmitted the inside of the infrared transmissive material which comprises a top table can be irradiated from the back surface side of a board | substrate, and the measurement by transmitted illumination is attained. At this time, the substrate is placed on the entire top surface of the top table in an in-contact state, so that even when pressed with a processing tool, the substrate is not bent and damaged.

The figure which shows the structure of the board | substrate processing apparatus which employ | adopted the table | surface with transmitted illumination which is one Embodiment of this invention. The figure which shows the structure of the principal part of the table with transmitted illumination in FIG. The figure which shows the structure of the principal part of the table with transmitted illumination which is other one Embodiment of this invention. The figure which shows the structure of the principal part of the table with transmitted illumination which is other one Embodiment of this invention. The figure which shows the structure of the principal part of the table with transmitted illumination which is other one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a substrate processing apparatus that performs laser scribing processing after positioning the substrate with respect to a silicon substrate having an alignment mark formed on one side of the substrate will be described as an example. The alignment mark is formed of a material such as a metal thin film that does not transmit infrared rays. Further, when the silicon substrate is placed on the processing table of the processing apparatus, it is assumed that the surface on which the alignment mark is formed is in contact with the table surface for the convenience of the process.

FIG. 1 is a schematic configuration diagram of a substrate processing apparatus LS1 employing a table with transmitted illumination according to the present invention. FIG. 2 is an enlarged view showing a main part of the table with transmitted illumination.
First, the overall configuration of the substrate processing apparatus LS1 will be described. A slide table 2 is provided that reciprocates in the front-rear direction (hereinafter referred to as the Y direction) of FIG. 1 along a pair of guide rails 3 and 4 arranged in parallel on a horizontal base 1. A screw screw 5 is disposed between the guide rails 3 and 4 along the front-rear direction, and a stay 6 fixed to the slide table 2 is screwed to the screw screw 5. The slide table 2 is formed so as to reciprocate in the Y direction along the guide rails 3 and 4 by forward and reverse rotation (not shown).

  A horizontal pedestal 7 is arranged on the slide slide table 2 so as to reciprocate in the left-right direction (hereinafter referred to as X direction) in FIG. A screw screw 10 that is rotated by a motor 9 is threaded through a stay 10a fixed to the pedestal 7, and the pedestal 7 is moved along the guide rail 8 in the X direction by rotating the screw screw 10a forward and backward. Move back and forth.

  Infrared light sources 23 and 24 are provided outside the moving range of the pedestal 7 so that infrared light is incident on the side surface of the top table 20 described later.

On the pedestal 7, a turntable 12 that can be rotated by a rotation mechanism 11 is provided. The upper surface of the rotary table 12 is a horizontal plane and serves as a sub-table for supporting a top table 20 described later. In addition, when the area of the substrate to be processed is considerably larger than the size of the turntable 12, a subtable different from the turntable 12 is placed, and the turntable and the subtable are made separate members. Good.
A top table 20 using a glass material, which is a material that can transmit infrared light from the infrared light sources 23 and 24, is placed on the upper surface of the rotary table 12 (sub-table). The top table 20 has a rectangular parallelepiped shape.

  As shown in FIG. 2, the top table 20 has a V-shaped groove 21 that opens toward the bottom surface 20 a, and the V-shaped groove 21 forms inclined surfaces 20 b and 20 c inside the top table 20. is there. The inclined surfaces 20b and 20c are at an angle of 45 degrees with respect to the bottom surface 20a and the top surface 20d. The V-shaped groove 21 is arranged in parallel with the side surfaces 20e and 20f, and both ends of the groove reach the side surface 20g and the side surface 20h. Therefore, the V-shaped groove 21 has a triangular prism shape having a cross section of a right isosceles triangle as viewed from the side surface 20g (20h).

  A metal block 22 (for example, an iron block) whose outer shape has the same triangular prism shape as the V-shaped groove 21 and whose surface is mirror-finished is fitted into the V-shaped groove 21. Thereby, the inclined surfaces 22b and 22c of the metal block 22 in contact with the inclined surfaces 20b and 20c of the top table 20 form a reflection surface for infrared light. That is, the inclined surfaces 22b and 22c of the metal block 22 function as reflective surfaces that reflect infrared light incident from the normal direction of the side surfaces 20e and 20f and emit in the normal direction of the upper surface 20b.

In the above embodiment, the V-shaped groove 21 is formed. However, as shown in FIG. 3, a trapezoidal groove 31 is formed instead of the V-shaped groove, and a trapezoidal metal block 32 is formed. The distance between the reflecting surfaces 32c and 32d may be increased. By adjusting the distance between the two reflecting surfaces, it is possible to adjust the range for transmitting illumination on the upper surface 20b.
Moreover, two V-shaped grooves and trapezoidal grooves are orthogonally crossed to form a cruciform groove (in this case, the end of each groove does not reach the side surface of the table), and further corresponds to this cruciform groove It is also possible to make the reflective surface into four surfaces so as to fit the metal block so that infrared light from any of the side surfaces 20e, 20f, 20g, and 20h can be reflected.

  The silicon substrate S to be processed is placed on the top table 20 by a robot hand (not shown) or an operator's manual work. At this time, the alignment mark formed on the silicon substrate S is placed in contact with the upper surface 20 b of the top table 20. Therefore, the surface of the silicon substrate S on which the alignment mark is formed becomes the back surface, and the surface on which the scribing is performed becomes the front surface.

  Above the top table on which the silicon substrate S is placed, a laser beam optical system 14 that irradiates the laser beam emitted from the laser power source 13 in a desired beam shape (for example, an ellipse), and a nozzle that injects a coolant 16, a cutter wheel 17 for forming a trigger crack when the substrate is scribed, and cameras 25 and 26 for confirming the positions of the alignment marks are attached.

Next, the operation of laser scribe processing by the substrate processing apparatus LS1 will be described.
With the side surfaces 20e and 20f of the top table 20 set at positions facing the infrared light sources 23 and 24, the top table 20 is placed so that the back surface of the silicon substrate S is in contact with the top surface 20b of the top table 20. When infrared light is irradiated from the infrared light sources 23 and 24, the infrared light enters the top table 20 from the side surfaces 20e and 20f, and the inclined surfaces 22c and 22d of the metal block (the inclined surfaces 20c and 20c of the top table 20). And reflected from the upper surface 20b. The infrared light incident from the back surface of the silicon substrate S is transmitted through the substrate, and at this time, the transmitted images reflecting the positions of the alignment marks on the silicon substrate S are detected by the cameras 25 and 26. . Therefore, the rotation table 12 and the base 7 are driven with reference to the position of the alignment mark while monitoring the images of the cameras 25 and 26, thereby positioning the silicon substrate S with respect to the top table 20.

When the positioning is completed, the top table 20 is subsequently moved, a trigger crack is formed at a desired position by the cutter wheel 17, and the laser irradiation position is aligned with the scribe line, and then the laser irradiation and the refrigerant immediately after. Laser scribing is performed by performing injection.
With the above operation, the front side scribing process can be performed with reference to the alignment mark on the back surface of the silicon substrate S.

Next, another embodiment of the present invention will be described. FIG. 4 is a view showing a main part of a table with transmitted illumination according to the second embodiment. In the figure, parts that are the same as those in FIG.
In the present embodiment, the reflection surface formed inside the top table 20 is formed by the metal thin films 27c and 27d attached to the inclined surfaces 20c and 20d without using the metal block 22 (see FIGS. 1 and 2). I am doing so. That is, the metal thin films 27 c and 27 d are formed on the inclined surfaces 20 c and 20 d of the top table 20. Specifically, for example, the reflective surface is formed by forming an aluminum film or the like by vapor deposition, sputtering, or the like. Also with this metal thin film, infrared light incident from the side surface can be reflected and sent to the upper surface.

FIG. 5 is a diagram illustrating a main part of a table with transmitted illumination according to the third embodiment. In the figure, parts that are the same as those in FIG.
In the present embodiment, the top screen 20 is not cut out to form the V-shaped groove 21, but the reflection screens 28c and 28d are formed inside the top table by laser irradiation. That is, the laser beam is focused on a desired position in the top table and scanned to melt the inside and create a reflective screen composed of an inclined plane. This reflection screen can also reflect infrared light incident from the side surface and send it to the upper surface.

  As mentioned above, although the typical Example of this invention was described, this invention is not necessarily specified only by said Example, It is possible to modify and change suitably within the range which does not deviate from a claim. is there.

  The present invention can be applied to a processing apparatus that requires positioning of an infrared transparent substrate such as a silicon substrate.

S solar cell substrate 7 pedestal 11 rotating mechanism 12 rotating table (sub-table)
20 Top table 21 V-shaped groove 22 Metal block 22b, 22c Inclined surface (reflective surface) of metal table
27c, 27d Metal thin film (reflection surface)
28c, 28d Reflective screen (reflective surface)
31 Trapezoidal groove 32 Metal block

Claims (4)

An infrared light source;
A metal sub-table in which a movable mechanism is attached to the lower part and a table placing surface for placing the top table on the upper part is formed,
A bottom surface that is in contact with the table mounting surface of the sub-table, a top surface that is mounted in a state of being in contact with the entire back surface of the substrate, and an incident side surface on which the infrared light of the infrared light source is incident. Consisting of a top table made of material,
Inside the top table, and below the position on which the substrate is placed, a reflective surface that reflects infrared light incident from the incident side surface toward the upper surface is provided,
A table for transmission illumination, wherein the infrared light is irradiated to a substrate through an infrared transmitting material constituting a top table.   The table for transmitted illumination according to claim 1, wherein the reflecting surface is formed by a surface of a metal block embedded in a space formed by cutting out a part of a top table.   The transmitted light table according to claim 1, wherein the reflecting surface is provided with an infrared light reflecting film on an inclined surface formed by cutting out a part of a top table. The table for transmitted illumination according to claim 1, wherein the reflecting surface is a reflecting screen formed by laser irradiation on a part of the top table.

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