KR-102962825-B1 - APPARATUS OF HBM STRUCTURE OPTICAL INSPECTION USING BESSEL BEAM

Abstract

An optical inspection device for an HBM (High Bandwidth Memory) structure is disclosed, comprising: an optical module that generates a Bessel beam and irradiates it onto an HBM structure; and a processor that performs a process for inspecting the HBM structure using a reflected signal of the Bessel beam reflected by at least one point of the HBM structure, wherein the processor identifies an interference pattern in which the reflected signals overlap and analyzes the interference pattern to detect a defect in the HBM structure.

Inventors

• 김형우
• 선상필
• 신성욱
• 홍수민
• 박규원

Assignees

• 주식회사 블루타일랩

Dates

Publication Date

20260512

Application Date

20250915

Claims (10)

1. An optical module that generates a Bessel beam and irradiates it onto a High Bandwidth Memory (HBM) structure; and A processor that performs a process for inspecting the HBM structure using a reflected signal of the Bessel beam reflected by at least one point of the HBM structure; The above processor is, Identify the interference pattern in which the above reflected signals overlap, Detect defects in the HBM structure by analyzing the interference pattern above, A first interference intensity between the core beam and the side lobe beam constituting the Bessel beam is obtained from the above interference pattern, and Based on the first interference intensity above, it is determined whether a phase difference occurs between the core beam and the side lobe beam, and An optical inspection device for an HBM structure that detects surface defects on a die layer to which the reflected signal is reflected among a plurality of die layers constituting the HBM structure according to the above verification result.
2. delete
3. In paragraph 1, The above processor is, An optical inspection device for an HBM structure that confirms that a phase difference has occurred when there is a difference between the first reference interference strength calculated for the case where there is no phase difference and the first interference strength.
4. In paragraph 1, The above processor is, A second interference intensity between a first reflected signal reflected from a first point of the HBM structure and a second reflected signal reflected from a second point of the HBM structure is obtained from the above interference pattern, and Based on the second interference intensity, it is determined whether a phase difference occurs between the first reflected signal and the second reflected signal, and An optical inspection device for an HBM structure that detects interlayer defects between the first point and the second point based on the above verification result.
5. In paragraph 4, The above processor is, An optical inspection device for an HBM structure that confirms that a phase difference has occurred when there is a difference between a second reference interference strength calculated by reflecting the thickness of each die layer set in advance and the second interference strength.
6. In paragraph 1, An optical inspection device for an HBM structure, further comprising: a first light receiving module that receives the reflected signal coaxially with the Bessel beam irradiated from the optical module.
7. In paragraph 6, It further includes a shooting module for capturing a surface image of the above HBM structure, and The above processor is, An optical inspection device for an HBM structure that detects surface defects of the HBM structure by analyzing the surface image above.
8. In Paragraph 7, The above processor is, An optical inspection device for an HBM structure that identifies whether there are defects in the inner layer of the HBM structure based on the analysis results of the surface image and the analysis results of the interference pattern.
9. In paragraph 1, An optical inspection device for an HBM structure, further comprising: a second light receiving module that receives the reflected signal along an axis different from the Bessel beam irradiated from the optical module.
10. In paragraph 1, The above processor is, An optical inspection device for an HBM structure that, when the above-mentioned reflected signal is reflected from a preset lower layer among a plurality of die layers of the HBM structure, verifies the degree of self-healing restoration of the reflected signal by comparing the electric field of the reflected signal with the electric field of the self-healing restoration signal, and then analyzes the interference pattern.

Description

Apparatus of HBM Structure Optical Inspection Using Bessel Beam The present disclosure relates to an optical inspection device for a semiconductor memory structure, and more specifically, to an optical inspection device for detecting defects that may occur in the stacked structure of a High Bandwidth Memory (HBM) structure using a Bessel Beam. With the recent rapid increase in data throughput, the demand for improved performance in memory systems is continuously rising, and consequently, high-bandwidth memory technologies such as HBM are attracting attention. The HBM structure has a three-dimensional structure in which multiple DRAM die layers are stacked vertically and connected via TSV (Through Silicon Via), enabling high memory capacity and bandwidth to be realized in a limited space. However, the complex multilayer stacking structure of such HBMs increases the likelihood of various types of defects occurring during the manufacturing process. In particular, surface defects in each die layer, misalignment between layers, poor bonding of microbumps, and microcracks around TSVs can directly affect the electrical performance and reliability of HBMs, leading to a need for technology to accurately detect these defects. In conventional technology, X-ray-based Automated Optical Inspection (AOI) systems or infrared-based inspection methods have been primarily used for the inspection of HBM structures. However, these conventional technologies have several fundamental limitations. For example, X-ray-based systems may have difficulty accurately distinguishing minute defects in the micrometer range, and in particular, it is difficult to individually identify complex defects occurring simultaneously in adjacent layers. Infrared-based methods also had limitations, such as difficulty detecting defects in the underlying layer due to shielding by TSVs and being unsuitable for in-line process inspection. Due to these limitations, there is an urgent need for the development of new inspection technologies capable of accurately and efficiently detecting various types of defects that may occur in high-density 3D memory structures such as HBM. In particular, there is a growing need for innovative optical inspection methods that can simultaneously detect surface and interlayer defects while fundamentally solving the problem of metal layer shielding. FIG. 1 is a conceptual diagram of an optical inspection device according to one embodiment of the present disclosure. FIG. 2 is a drawing for explaining another embodiment of the light receiving module illustrated in FIG. 1. FIG. 3 is a drawing for explaining an HBM structure according to one embodiment of the present disclosure. FIG. 4 is a drawing for explaining an interference pattern formed by a Bessel beam according to one embodiment of the present disclosure. FIG. 5 is a drawing for explaining an inspection method according to one embodiment of the present disclosure. Throughout this disclosure, the same reference numerals denote the same components. This disclosure does not describe all elements of the embodiments, and general content in the art to which this disclosure pertains or content that overlaps between embodiments is omitted. The terms 'part, module, component, block' as used in the specification may be implemented in software or hardware, and depending on the embodiments, a plurality of 'parts, modules, components, blocks' may be implemented as a single component, or a single 'part, module, component, block' may include a plurality of components. Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components. The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms. Singular expressions include plural expressions unless there is an obvious exception in the context. In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context. The operating principles and embodiments of the present disclosure will be described below with reference to the attached drawings. In this specification, the term "device according to the present