Correction method of photomask and mfg. method of semiconductor element

Abstract

The photomask correction method includes preparing a photomask substrate having a mask pattern including a phase shift pattern, removing a part of the mask pattern to form a reference hole, irradiating an ion beam from an ion beam source to a region including the reference hole to secondary charge Particles are emitted from the above-mentioned reference hole, the detector detects secondary charged particles to identify the position of the reference hole, calculates the relationship between the position of the reference hole and the defect position of the mask pattern, and irradiates the ion beam from the ion beam source to the defect to correct the defect according to the positional relationship. The pattern of the reference hole viewed in the direction perpendicular to the upper surface of the photomask substrate is a rectangle, and its long side direction is parallel to the long side direction of the phase shift pattern.

Description

technical field [0001] The present invention relates to a method of correcting a photomask used in the manufacture of a semiconductor integrated circuit, and more particularly to a method of correcting a photomask for repairing a defect by irradiating a focused ion beam (FIB) to a defective portion of the photomask . Background technique [0002] In the case of defect correction of photomasks using focused ion beams, in order to collectively correct information drift due to charging or drift due to thermal expansion of the mask or mask holder, single point drift correction (one point drift correction). In the case of this single-point drift correction, a pinhole is formed in the pattern of the photomask, and the ion beam is moved to the correction position using the pinhole as a reference point, thereby improving the correction accuracy. Below, see Figure 8 to Figure 10 A specific example of single-point drift correction will be described. [0003] First, a focused ion b...

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Problems solved by technology

[0007] In addition, as mentioned above, because many secondary ions are blocked by the side wall on one side of the detector 24 in the past, there is a problem that the secondary ions from the bottom of the pinhole, that is to say, from the exposed surface of the substrate, cannot reach the detector with good efficiency. device problem

[0008] In this way, if a conventional photomask correction method using single-point drift correction is used, when a phase shift mask is used as a photomask, the area where the phase shift effect (phase shift effect) cannot be obtained becomes large, Therefore, there is a problem that a suitable projection image cannot be obtained

In addition, there is a problem that the positional accuracy (recognition accuracy) of the pinhole for reference cannot be obtained sufficiently.

Furthermore, there is also the problem that the secondary ions (secondary charged particles) from the pinhole cannot be incident on the detector with good efficiency.

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