JPS6363905A - Photoelectric sensor used in positioning device - Google Patents

Abstract

PURPOSE:To speed up response, by arranging a plurality of cells comprising photoelectric elements and fuses in a 1-D or 2-D array. CONSTITUTION:Cells made up of photoelectric elements D11, D12... and fuses F11, F12... are arranged in two arrays on a 2-D plane to build a photoelectric sensor together with a column control logic circuit 101 and a line control logic circuit 102. Necessary and unnecessary light receiving sections are selected according to the shape of an optical signal received and the cells corresponding to the unnecessary light receiving sections are selected according to specifications of the circuits 101 and 102 to blow the corresponding fuses. Thus, the light receiving section of the photoelectric sensor is allowed to match the shape of an optical signal received and this eliminates unnecessary light receiving sections thereby speeding up the response of the photoelectric sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a photoelectric sensor for positioning.

[Prior Art] In LSI manufacturing using a reduction projection exposure apparatus, patterns of several layers or more are sequentially formed on a wafer.
If the superposition error of different glabella patterns is not kept below a certain value, the conductive or insulating state between the glabella will not be as intended, and this will lead to problems with LSI performance. For a circuit with a line width of 1 μm, a positional deviation of about 0.2 μm is allowed at most. Therefore,
Positioning, which is performed by superimposing a projected image of a pattern on a reticle and a pattern already formed on a wafer, is an extremely important technique.

FIG. 2 is a configuration diagram showing an example of a conventional alignment device. The laser beam from the laser beam (4) passes through a beam expander (5), a cylindrical lens (6), and is shaped into an elongated elliptical beam, which is then shaped into an elongated elliptical beam by a mirror (7), a lens (8), a beam splitter (9), and a lens GO. through the mirror (ID
is reflected from the bottom surface of the reticle R by the mirror (support).
is reflected to the entrance pupil (1a) of the projection lens (1). The laser beam passing through the projection lens (1) forms an image on the wafer W as a spot light LAY. Since alignment marks are previously formed on the wafer W, when the spot light LAY irradiates the marks, specularly reflected light and diffracted light of the spot light LAY are generated. The optical information from these marks is the projection lens (1), the incidence @(la), and the mirror (goods).

(lυ) is reflected by the beam splitter (9) through the lens beam and reaches the spatial filter. The spatial filter beam is conjugate with the entrance pupil (la) of the projection lens (1), and the Only the specularly reflected light (O-order diffracted light) is blocked.Diffracted light and scattered light from the surface (mark) of the wafer W are displaced relative to the specularly reflected light depending on the spatial frequency.

Therefore, the spatial filter (g) passes only the diffracted light and scattered light and focuses the light on the light receiving element (5) via the condensing lens a. The light receiving element (5) inputs a photoelectric signal SA corresponding to the intensity of the diffracted light or scattered light to the alignment signal processing circuit. The processing circuit (lffl) also inputs the position information PD from the measuring device (3) and detects the generation position of the photoelectric signal SA according to the diffracted light from the mark.The control device α7) detects the position of the detected mark. Based on the information, the drive parts are controlled and the stage (2 to 8
Make it move.

If marks on the wafer W are provided to accompany each of a plurality of chips on the wafer, the center of the chip and the optical axis AX can be accurately located by detecting the position of each mark. It is possible to match them.

[Problem that the invention seeks to solve]

By the way, the light-receiving element (light sensor) (4) used in the above-mentioned alignment device has to change the size of the sensor depending on the optical signal it receives.Therefore, it is necessary to make various shapes depending on the content of the optical signal it receives. Furthermore, if the light-receiving area is increased, the response speed of the sensor becomes slower, so there is another problem that the response of light signals that can be received is limited depending on the sensor used.

The present invention was made to solve the above problems, and
It is an object of the present invention to provide a photoelectric sensor for alignment that allows the shape of a received optical signal to be easily and quickly created.

[Means for solving problems]

In order to achieve the above objective, the photoelectric sensor used in the alignment device is made up of a large number of cells consisting of photoelectric elements and fuses.
It is configured by arranging it in one dimension or two dimensions.

(Function) In the photoelectric sensor configured as described above, by blowing out the fuses of unnecessary cells in the light receiving section, the light receiving section can be formed in any shape, so that the received optical signal can be It becomes possible to form an optical sensor including a light receiving section according to the shape.

(Embodiment of the present invention) Figure 1 is a configuration diagram of an optical sensor used in the alignment device.
Eye...DmI is a photodiode, Fl...
F is a fuse, (101) is a row control logic circuit, (
102) is a column control logic circuit.

As shown in the figure, each cell constituting the photoelectric sensor is connected to a photodiode (DIl, DI2...) and a fuse (F rl
-F12...) and are arranged on a two-dimensional plane to form a photoelectric sensor together with a row control logic circuit (101) and a column control logic circuit (102).

When using the photoelectric sensor configured as described above as a photoelectric sensor for an alignment device, the necessary and unnecessary light-receiving parts are selected according to the shape of the received optical signal, and the unnecessary light-receiving parts are replaced with unnecessary light-receiving parts. By specifying the logic circuits (101) and (102) for the corresponding cells, the light receiving section of the photoelectric sensor of the selection device matches the shape of the received optical signal.

Although this embodiment is an example of a fuse blowing type, a method such as a junction shortening type may be used as long as an arbitrary photodiode can be cut.

(Effects of the Invention) In the present invention, the photoelectric sensor used in the alignment device is constructed by arranging a large number of cells each consisting of a photodiode and a fuse in one or two dimensions. I was able to improve the effect.

■It is now possible to form a light-receiving part in any shape depending on the shape of the received optical signal, which not only has the advantage of allowing the development of many types of sensors in a short time, but also eliminates unnecessary light-receiving parts. Therefore, the junction capacitance is reduced and the response of the photoelectric sensor can be increased.

■ By creating a sensor with a light-receiving surface that matches the shape of the received optical signal, the light-receiving surface can be used as it is in the space (IL) 3 Mi
b day f, ffi? , it becomes possible to omit the condenser lens α4) and the condenser lens α4).

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a photoelectric sensor showing an embodiment of the present invention;
FIG. 2 is a configuration diagram of the alignment device. In the figure, DIl, D+2... are photodiodes, Fil
, FI2... Hughes, (101), (102
) are control logic circuits in one row and one column, respectively. Agent Patent Attorney Tadashi Sato Figure 1

Claims (1)

[Claims] Used in an alignment device characterized in that a large number of cells each consisting of a photoelectric element and a fuse are arranged one-dimensionally or two-dimensionally so that the fuses can be cut according to the shape of the received light beam. photoelectric sensor.