JP4529736B2 - Reticle - Google Patents

Description

  The present invention relates to a reticle used in lithography technology such as semiconductor manufacturing.

  In lithography technology in the semiconductor manufacturing process, the reticle is indispensable. However, the handling environment can be said to be an environment in which static electricity is easily charged due to transportation by an operator, indoor airflow, handling by a reticle case, and the like. If static electricity is accumulated in the reticle, there is a risk of electrostatic breakdown of the semiconductor circuit pattern due to the discharge of the static electricity. However, there are many cases where the electrostatic breakdown of the pattern is not noticed when the reticle is used, and many are discovered in the subsequent inspection process. Since the electrostatic breakdown of such a reticle is a serious concern, countermeasures are taken, such as a charge removal process using an ionizer or insulating the circuit and its peripheral part on the reticle (insulation ring). However, it is difficult to monitor (monitor) the damage state and usage environment actually given to the reticle. As a means for monitoring the damage state and usage environment applied to the reticle, a reticle in which an electrostatic breakdown check pattern is provided outside a light shielding pattern formed around a circuit pattern has been proposed (Patent Document 1). ).

Known documents are shown below.
JP-A-5-107740

  In the case of a normal reticle, it is possible to prevent electrostatic charges by using an ionizer, an insulating ring, etc., but it is very important to confirm whether or not electrostatic damage has actually occurred in the reticle being used. Have difficulty. As a means for confirmation, for example, there is a method in which a check pattern is formed on a reticle and a visual inspection is performed (Patent Document 1). However, the reticle is usually housed in the reticle case, and it is extremely difficult to confirm the presence or absence of electrostatic breakdown by visually checking the pattern for checking electrostatic breakdown of the reticle in the reticle case. Another method for confirming the presence or absence of electrostatic breakdown is a method of transferring a pattern on a reticle onto a wafer. However, it requires labor and time for transferring onto the wafer, and it is necessary to observe the transferred pattern under a microscope, which is complicated.

  An object of the present invention is to solve the above-described problems, and to provide a reticle that makes it possible to monitor the presence or absence of electrostatic breakdown of a circuit pattern of a reticle by a simple operation. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the invention of claim 1 is a ring-shaped insulation that surrounds the transfer effective region that is outside the transfer effective region and can directly check the energized state. The reticle comprises a pattern for confirming electrostatic breakdown having a ring shape in a region .

  Since the reticle of the present invention has such a configuration, it is possible to directly check the energized state from the electrostatic breakdown confirmation pattern without affecting the circuit pattern in the effective transfer area and without visual inspection. Therefore, the present invention can be applied to a reticle used for manufacturing a product such as a semiconductor integrated circuit, and can be easily inspected for electrostatic breakdown and monitored for the presence or absence of electrostatic breakdown.

  According to a second aspect of the present invention, in the reticle according to the first aspect, the line width of the electrostatic breakdown confirmation pattern is narrower than the width of the minimum line existing in the circuit pattern formed in the transfer effective region. This is a reticle characterized in that

  In the reticle of the present invention, electrostatic breakdown is easily generated by making the line width of the electrostatic breakdown confirmation pattern narrower than the minimum line width existing in the circuit pattern formed in the transfer effective region. The inspection can be carried out reliably.

  The minimum width of the circuit pattern formed in the transfer effective area of the present invention does not necessarily mean a pattern forming a circuit, but as a minimum width of a pattern formed on a reticle for manufacturing a single element or various electric elements. Also good.

  According to a third aspect of the present invention, there is provided the reticle according to the first or second aspect, wherein the electrostatic breakdown confirmation pattern is a meandering pattern having a repetitive shape with a short pitch. It is a thing.

  In the reticle according to the present invention, the electrostatic breakdown confirmation pattern is a meandering pattern having a short repeated pitch that is likely to cause electrostatic breakdown. it can.

  According to a fourth aspect of the present invention, in the reticle according to any one of the first to third aspects, the electrostatic breakdown confirmation pattern is a meandering pattern having acute corner portions. And a reticle.

  In the reticle of the present invention, the pattern for confirming electrostatic breakdown is a meandering pattern having sharp corners where electrostatic breakdown is likely to occur. it can.

  According to the reticle of the first aspect of the present invention, before using the reticle, by confirming the energization state of the electrostatic breakdown confirmation pattern using an energization confirmation device such as a tester, The presence or absence of electrostatic breakdown can be monitored.

  According to the reticles according to the second, third, and fourth aspects of the present invention, it is possible to more reliably monitor the presence or absence of electrostatic breakdown of the circuit pattern of the reticle.

  The best mode for carrying out the present invention will be described below.

  In the reticle of the present invention, an electrostatic breakdown confirmation pattern having a shape capable of directly confirming the energized state is provided outside the effective transfer area. FIG. 1 is a schematic explanatory view of an embodiment of a reticle according to the present invention viewed in a plane. An insulating region is provided in a ring shape between the effective transfer region 1 on the reticle A and the peripheral conductive portion 5 so as to surround the effective transfer region 1. A conductive pattern 3 for confirming electrostatic breakdown is formed on a substantially ring on the insulating region, and in this pattern 3, the insulating region is divided into insulating rings 2-1 and 2-2. The conductive pattern 3 is divided at one place, and conductive pads 4-1 and 4-2 are connected to the divided ends (FIG. 1 (b)). For one of the conductive pads, one end portion of the divided conductive pattern may be connected to the peripheral conductive portion with a conductive line, and this may be used as a pad.

The line widths of the conductive pattern and the conductive line are set to be equal to or smaller than the effective minimum line width in the circuit so that electrostatic breakdown is likely to occur. In addition, it is preferable that at least a part of the conductive pattern is formed in a meandering pattern having a repetitive shape with a short pitch (FIG. 1 (c) c 1), and an acute corner portion of 90 ° or less. A serpentine pattern having the following is preferable (FIG. 1 (c) c2).

  The reticle of this example is configured as described above, and the user confirms energization by applying a tester or the like to the conductive pads 4-1 and 4-2 before using the reticle A. In the energized state, the conductive pattern 3 does not cause electrostatic breakdown, which means that the pattern in the effective region 1 having a line width larger than that of the conductive pattern 3 does not cause electrostatic breakdown. Further, when energization cannot be confirmed, the conductive pattern 3 is disconnected due to electrostatic breakdown, which means that the reticle A is used in an environment causing electrostatic breakdown, and the pattern in the effective area 1 is This indicates that there is a possibility of disconnection.

  As in the above example, it is preferable that the conductive pattern and the conductive line include an acute pattern that is equal to or smaller than the effective minimum line width in the circuit and is 90 ° or smaller in order to easily cause electrostatic breakdown. However, the shape, line width, and length of both the conductive pattern and the conductive line may be determined according to the use situation. Further, as in this example, it is preferable to provide a conductive pattern on the conductive pattern for contacting the probe of an energization confirmation device such as a tester. The conductive pads are preferably installed at the same position in consideration of the shape of the tester and the like, but the positions may be arbitrarily determined depending on the use situation. In addition, it is possible to easily check whether or not electrostatic breakdown has occurred in the conductive pattern by inspecting the energization state between the conductive pads at both ends of the conductive pattern with a tester or the like at any occasion. Can do. If energization of this conductive pattern is not confirmed, it is easily considered that the conductive pattern is damaged due to electrostatic breakdown. Therefore, it suggests that the environment in which the reticle is used may cause electrostatic breakdown. In addition, by providing the conductive pattern outside the inner insulating ring, this inspection can be performed without affecting the circuit pattern in the transfer effective region. Therefore, the reticle used for the manufacture of products such as semiconductor integrated circuits. And can be easily inspected.

  The reticle of the present invention is not limited to semiconductor manufacturing, but is also used for reticles used in lithography techniques such as surface acoustic wave filters, magnetic head elements, and optical elements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of an embodiment of a reticle according to the present invention viewed in plan, (a) is a schematic explanatory view of the whole viewed in plan, and (b) is a schematic description of a pad and a conductive pattern enlarged and viewed in plan FIG. 4C is a schematic explanatory view in which a part of an example of the conductive pattern is enlarged and viewed in a plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Effective area | region 2-1 ... Insulation ring 2-2 ... Insulation ring 3 ... Conductive pattern 4-1 ... Conductive pad 4-2 ... Conductive pad 5 .... Peripheral conductive parts

Claims (4)

It is provided with a pattern for confirming electrostatic breakdown having a ring shape in a ring-shaped insulating region that is outside the effective transfer region and encloses the effective transfer region that can directly check the energized state. Reticle.   2. The reticle according to claim 1, wherein the line width of the electrostatic breakdown confirmation pattern is narrower than the width of the minimum line existing in the circuit pattern formed in the transfer effective region.   3. The reticle according to claim 1, wherein the electrostatic breakdown confirmation pattern is a meandering pattern having a repeated shape with a short pitch. 4. The reticle according to claim 1, wherein the electrostatic breakdown confirmation pattern is a meandering pattern having acute corner portions.