JP2912167B2 - Laser redundancy device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser redundancy device and, more particularly, to a laser redundancy device for cutting a part of a circuit using a laser beam in order to repair a defective semiconductor chip.

[0002]

2. Description of the Related Art In recent years, as the degree of integration and quality of semiconductor integrated circuits has increased, high reliability has also been pursued in semiconductor manufacturing apparatuses. With respect to higher integration of semiconductor integrated circuits, high-density storage circuit devices called ultra-large-scale semiconductor integrated circuits (ultra-large scale integrated circuits) are being developed. Conventionally, in order to produce this high-density storage circuit device at a lower price, a circuit having redundant bits has been devised. This is a method in which a circuit device having a larger number of bits than the desired number of memory bits is prepared, and when the original bit is defective, a fuse prepared in advance is blown to make use of this redundant bit.

On the other hand, in order to improve the quality of a semiconductor integrated circuit, there is a method of partially cutting the circuit in order to obtain a more accurate integrated circuit. Therefore, in any method for achieving high integration and high quality of a semiconductor integrated circuit, a desired fuse or wiring must be blown. A laser redundancy device is required to blow the fuse or the wiring.

FIG. 5 is a block diagram showing an example of a conventional laser redundancy device. In the figure, a stage 102 that can move in the X-Y2 direction is installed on a vibration isolation table 101. On the stage 102, a wafer 100 requiring trimming is mounted. On this wafer 100, a laser light source 103, an optical system 105, a mirror 10
6, an alignment control system 108, an optical system 109, an aperture 120, and an optical system 111 are provided.

Next, the operation of this laser redundancy device will be described. First, a laser beam 104 emitted from a laser light source 103 is used for wafer alignment.
After the laser power is adjusted by the optical system 105, the laser beam passes through the mirror 106, the optical system 109, the aperture 120, and the optical system 111, and irradiates the alignment mark portion on the wafer 100.

[0006] The reflected light from the wafer alignment mark portion due to the laser beam irradiation is reflected by the optical system 111 and the aperture 1.
The laser beam 107 is transmitted through the optical system 109 and is incident on the mirror 106 and reflected there. The laser beam 107 is incident on the alignment control system 108 to perform wafer alignment.

After the completion of the wafer alignment, the laser light 104 emitted from the laser light source 103 is adjusted to an optimum power for blowing the fuse by the optical system 105, and is subsequently irradiated onto the aperture 120 by the optical system 109. Since a rectangular or round opening is formed in the aperture 120, the light beam cross section of the laser beam passing through the aperture 120 has the same shape as the opening of the aperture 120 and is shaped into an appropriate size.

The shaped laser light that has passed through the aperture 120 is applied to a fuse on the wafer 100 by the optical system 111 and blows the fuse. When one fuse is blown, the stage 102 moves and the next one is blown by the same method as described above.

FIG. 6 is a perspective view of an aperture and a fuse for explaining a fuse blowing method of a conventional device. 5, the same components as those of FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. Also, in FIG. 6, to simplify the description,
Illustration of the optical systems 109 and 111 is omitted.

In FIG. 6, a laser beam 104 is incident on an aperture 120 and passes through a rectangular opening 121 formed in the aperture 120 to form a laser beam 122 having a light beam cross section shaped into a rectangular shape. Irradiation is performed on the fuse 123 above the reference numeral 100. Fuse 1
23 is melted by being heated by the shaping laser beam 122.

In addition, a plurality of laser light sources are provided, from which a plurality of laser beams are separately irradiated to a plurality of fuses on a semiconductor chip, and the plurality of fuses are blown at the same time, thereby improving the throughput. Another laser redundancy device has been conventionally known (Japanese Patent Laid-Open No.
-67654).

[0012]

However, the conventional laser redundancy device described with reference to FIGS. 5 and 6 has two problems. The first problem is that since the fuses are sequentially blown one by one, the processing capability (throughput) is low and the price of the semiconductor device is high.

The second problem is that the laser light 104 generated from the laser light source 103 has a variation in energy.
This variation is not sufficiently reduced even by the optical system 105 for adjusting the energy, so that the fuse may not be blown.

On the other hand, in the latter conventional laser redundancy apparatus using a plurality of laser light sources, although the throughput is improved, there is a problem that the apparatus is complicated, large-sized and expensive due to the use of a plurality of laser light sources. Also,
The second problem of the former conventional device described with reference to FIGS. 5 and 6, which is the second problem, is not improved at all by the fusing failure due to the variation in the energy of the laser beam.

The present invention has been made in view of the above points,
It is an object of the present invention to provide a laser redundancy device capable of improving the throughput and improving the fusing defect.

[0016]

According to the present invention, there is provided a laser light source for emitting laser light, comprising a plurality of laser light sources .
Multiple patterns of rectangular openings
An aperture formed in that region, the aperture
To an arbitrary distance in a two-dimensional direction horizontal to the aperture plane.
A moving aperture driving mechanism, a first optical system for irradiating the aperture with laser light emitted from the laser light source, and a plurality of shaped laser lights simultaneously obtained by passing through the aperture; A second optical system for irradiating, and an alignment control system for performing alignment for detecting a portion to be blown on the sample based on reflected light incident from the sample via the second optical system and the aperture. After the alignment by the alignment control system is completed,
The first optical system adjusts the power of the laser beam incident on the optical system to an optimal power for fusing, and the plurality of shaped laser beams transmitted through the second optical system are used to control the circuit on the sample. It is configured to blow a part.

[0017]

[0018]

[0019]

According to the present invention, one laser beam from a laser light source is shaped into a plurality of laser beams by passing through a plurality of apertures formed in the aperture. It is possible to simultaneously irradiate a part of the circuit to be blown on the sample.

Further, in the present invention, when a plurality of types of patterns including a plurality of rectangular openings are formed in the aperture, a plurality of patterns of an arbitrary type corresponding to the length and width of the fusing target are provided. A rectangular opening can be selected.

Further, according to the present invention, the aperture is driven by the aperture driving mechanism in the horizontal two-dimensional direction (the XY direction), so that the laser light passes through a plurality of aperture regions formed on the aperture. Area , high precision
It can be selected.

[0022]

Next, an embodiment of the present invention will be described. FIG. 1 shows a configuration diagram of an embodiment of the present invention. 5, the same components as those of FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 1, this embodiment employs optical systems 109 and 1
An aperture 110 having a predetermined opening is provided between the aperture 110 and the aperture 110, and an aperture driving mechanism 112 for controlling the movement of the aperture 110 in the horizontal direction (X-Y direction) is provided.

In the aperture 110, a plurality of patterns each having a plurality of openings are formed in different regions. That is, as shown in the plan view of FIG. 2, for example, an aperture pattern including a plurality of four types of openings is formed on the plane of the aperture 110, one type for each of the four regions.

In these regions, a first region in which two rectangular openings 113A and 113B of the same shape are provided in parallel, and two rectangular openings 113C and 113D of the same shape in the same manner are provided in parallel. A second region and four identical square openings 113E, 113F, 113G and 113
H is a third region in which two rows and two columns are arranged in a matrix, and three identical narrow rectangular openings 113I and 113J.
And 113K are provided in parallel with each other.

The aperture driving mechanism 112 is provided to move the aperture 110 in the horizontal direction and use the opening pattern of one of the four areas of the aperture 110. In FIG. 2, the laser light 10
4 irradiates the openings 113A and 113B. Therefore, the laser light transmitted through the aperture 110 becomes two laser lights.

The two laser beams are applied to the optical system 111 of FIG.
Thus, a part (usually a fuse or a wiring) of a circuit to be blown on the wafer 100 as a sample is simultaneously focused and irradiated, and blown.

Here, when the aperture 110 is moved in the X direction from the state of FIG. 2 by the aperture driving mechanism 112, the laser beam can be irradiated onto the openings 113C and 113D of FIG. Is the opening 11
Laser light can be irradiated on 3E to 113H.

As described above, according to this embodiment, by moving the aperture 110 by the aperture driving mechanism 112, it is possible to generate beams of various shapes and laser beams of different numbers. As a result, the aperture can be immediately moved to the wafer 100 having different fuse intervals and the wafers having different fuse lengths and fuse widths, and appropriate openings can be used, thereby enabling high-throughput processing with a high probability of success.

Next, a fuse blowing method according to the first embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. In FIG. 3, the laser light 104 is applied to the aperture 11 on the aperture 110.
3A and 113B, the openings 113A and 1B
13B, the two laser beams 115A
And 115B. These two shaped laser beams 1
15A and 115B are one fuse 1 on the wafer.
Irradiated at 16 locations and usually blown at two locations simultaneously.

Here, the fuse 116 is usually blown at two places at the same time. However, even if there is a disconnection failure due to the above-described variation in laser energy, the fuse can be blown at one of the two places. The probability that they cannot be fused is extremely low. Therefore, for example, if the success probability of fusing with one conventional laser beam is 50%, the success probability of fusing with two laser beams of the present embodiment is 75% (=
(1/2) + (1/2) × (1/2)), and when the success probability with one laser beam is 90%, the success probability of fusing with two laser beams is 99%. Significantly improved.

Here, the number of openings is two, but in the case of three openings, the success probabilities are further improved to 87.5% and 99.9%, respectively. According to this embodiment, the time required for blowing one fuse does not decrease as compared with the related art.

Next, a fuse blowing method according to a second embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. In FIG. 4, a laser beam 104 is applied to an aperture 11 on an aperture 110.
3C and 113D, the openings 113C and 1C
13D, the two laser beams 115C
And 115D.

The two shaped laser beams 115C and 11C
5D is separately irradiated to two fuses 116A and 116B arranged in parallel on the wafer, and blows them simultaneously. Therefore, according to the present embodiment, it is possible to improve the throughput as compared with the related art.

The present invention is not limited to the above embodiment. For example, the first and second embodiments are combined and, for example, four openings 113E to 113H formed on the aperture 110 shown in FIG. Of these, one fuse is blown by laser light passing through two openings (for example, 113E and 113F), and another fuse is blown by laser light passing through the remaining two openings. Thus, it is possible to simultaneously improve the probability of successful fuse blowing and the throughput.

Also, one fuse is blown using two laser beams passing through two of the four openings,
Further, the two fuses can be blown at the same time using the two laser beams passing through the remaining two openings.

Further, in the above embodiment, the aperture 110 having four types of openings as shown in FIG. 2 has been described. However, the present invention is not limited to this. May have only one type of opening and may not have the aperture driving mechanism 112. Even with this configuration, it is possible to achieve an improvement in the probability of successful fuse blowing or an improvement in throughput as compared with the related art.

[0037]

As described above, according to the present invention,
A plurality of shaped laser beams obtained by passing one laser beam from a laser light source through a plurality of apertures formed in an aperture are simultaneously irradiated on a part of a circuit to be blown on a sample. Therefore, the probability of successful fusing can be greatly improved when irradiating a single fusing object simultaneously, and when a plurality of fusing objects are separately irradiated, a plurality of Simultaneous fusing can greatly improve the throughput as compared with the conventional case.

Further, according to the present invention, an aperture in which a plurality of types of patterns including a plurality of openings are formed allows a plurality of arbitrary types of openings to be selected in accordance with the length and width of the object to be blown. It is possible to improve the probability of successful fusing and the throughput of various types of fusing targets.

Further, according to the present invention, by driving the aperture horizontally by the aperture driving mechanism,
Since the laser beam is selected from the multiple apertures formed on the aperture, the shape and number of multiple shaped laser beams can be changed immediately according to the fusing target. Therefore, the fusing can be performed immediately following changes in the interval, length, width, and the like of the fusing target, and the improvement of the fusing success probability and the improvement of the throughput can be realized simultaneously. As described above, according to the present invention, a large number of high-quality semiconductor devices can be supplied at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the device of the present invention.

FIG. 2 is a plan view of an example of an aperture which is a main part of FIG.

FIG. 3 is an explanatory view of a method for blowing a fuse of a first embodiment by the device of the present invention.

FIG. 4 is an explanatory view of a method for blowing a fuse of a second embodiment by the device of the present invention.

FIG. 5 is a configuration diagram of a conventional example.

FIG. 6 is an explanatory view of a fuse blowing method of a conventional device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Wafer 103 Laser light source 104 Laser light 105, 109, 111 Optical system 106 Mirror 108 Alignment control system 110 Aperture 112 Aperture drive mechanism 113A-113K Opening 115A-115D Shaped laser light 116, 116A, 116B Fuse

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-261083 (JP, A) JP-A-64-22494 (JP, A) JP-A-63-136545 (JP, A) JP-A-2- 11288 (JP, A) JP-A-5-114780 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 26/00-26/06

Claims (1)

(57) [Claims] 1. A laser light source for emitting laser light, a plurality
The pattern consisting of rectangular openings
An aperture formed in a region defined by the
At an arbitrary distance in a two-dimensional direction that is horizontal to the aperture plane.
A moving aperture driving mechanism, a first optical system for irradiating the aperture with laser light emitted from the laser light source, and irradiating the sample with a plurality of shaped laser lights simultaneously obtained by passing through the aperture; A second optical system, and an alignment control system for performing alignment for detecting a portion to be blown on the sample based on reflected light incident from the sample via the second optical system and the aperture. After the completion of the alignment by the alignment control system,
The first optical system adjusts the power of the laser beam incident on the optical system to the optimal power for fusing, and the plurality of shaped laser beams transmitted through the second optical system allow the circuit on the sample to operate. A laser redundancy device characterized by fusing a part.