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KR-102962218-B1 - METHOD FOR PREPARING PRINTED CIRCUIT BOARD

KR102962218B1KR 102962218 B1KR102962218 B1KR 102962218B1KR-102962218-B1

Abstract

A method for manufacturing a printed circuit board according to one embodiment of the present invention comprises: a substrate manufacturing step of manufacturing a ceramic substrate; a deposition step of depositing a deposition layer on both sides of the ceramic substrate; and a bonding step of positioning and bonding a metal sheet on the deposition layer, wherein the deposition layer comprises Ag and Ti, and the deposition amount of Ag per unit area is 3.50 g/ m² or more and 6.10 g/ m² or less, and the deposition amount of Ti per unit area is 0.61 g/ m² or more and 1.30 g/ m² or less.

Inventors

  • 이준호
  • 고정민
  • 조남태
  • 츠시마 에이키

Assignees

  • 주식회사 엘엑스세미콘
  • 가부시키가이샤 에프제이 콤포지트

Dates

Publication Date
20260508
Application Date
20200522

Claims (9)

  1. Substrate manufacturing step for manufacturing a ceramic substrate; A deposition step of depositing a deposition layer on both sides of the ceramic substrate; and A bonding step comprising positioning and bonding a metal sheet on the deposition layer; wherein the deposition step comprises a step of depositing a first layer containing Ti on each side of the ceramic substrate and a step of depositing a second layer containing Ag on each of the first layers, wherein in the deposition step, the second layer containing Ag is deposited on the first layer without being mixed with the first layer containing Ti. The bonding step includes the step of hot-pressing the metal sheet located on the deposition layer, and In the bonding step above, the material of the first layer included in the deposition layer reacts with the material included in the ceramic substrate to form a bonding layer, and the Ag material of the second layer included in the deposition layer diffuses into the metal sheet. The bottom surface of the bonding layer is in contact with the ceramic substrate, and the top surface of the bonding layer is in contact with the metal sheet. The deposition amount of Ag per unit area in the second layer is 3.50 g/ m² to 6.10 g/ m² , Method for manufacturing a printed circuit board.
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  3. In Paragraph 1, A method for manufacturing a printed circuit board in which the deposition amount of Ti per unit area in the first layer is 0.61 g/ m² or more and 1.30 g/ m² or less.
  4. In Paragraph 1, A method for manufacturing a printed circuit board in which the ceramic substrate comprises at least one of Si₃N₄ , AlN , and Al₂O₃ .
  5. In Paragraph 1, A method for manufacturing a printed circuit board in which the metal sheet comprises at least one of Cu, Al, Ni, and Fe.
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  9. In Paragraph 1, A method for manufacturing a printed circuit board in which the bonding layer comprises TiN.

Description

Method for preparing printed circuit board The present invention relates to a method for manufacturing a printed circuit board, and more specifically, to a method for manufacturing a printed circuit board capable of improving interlayer bonding strength. Recent electronic devices are becoming increasingly smaller, lighter, and more functional. To meet this demand, the application of build-up printed circuit boards (BPCs) is rapidly expanding, particularly for small devices, leading to a rapid increase in the use of multilayer printed circuit boards. Multilayer printed circuit boards enable wiring ranging from planar to three-dimensional configurations. Particularly in the industrial electronics sector, they are advantageous products for enhancing the integration density of functional components such as ICs (integrated circuits) and LSIs (large-scale integrations), as well as for the miniaturization, lightweighting, and high functionality of electronic devices, structural electrical functional integration, reduced assembly time, and cost reduction. A printed circuit board can be manufactured by bonding copper sheets to both sides of a ceramic substrate such as alumina ( Al₂O₃ ), aluminum nitride (AlN), or silicon nitride ( Si₃N₄ ). Bonding methods for printed circuit boards can be broadly divided into three types as follows: active metal brazing (AMB), which uses a paste composed mainly of Ag; direct bonding, which uses an oxide layer of a ceramic substrate for bonding; and diffusion bonding, which uses metal deposition and diffusion reactions. Among these, the active metal method has the problem of Ag diffusing to the edge regions during the operation of power semiconductor modules, while the direct junction method suffers from reduced thermal conductivity due to the oxide layer. In contrast, the diffusion junction method has the advantage of enabling the manufacture of printed circuit boards with excellent thermal shock characteristics because it can form a thin deposition layer hundreds of nanometers thick through solid-state reactions, requiring an extremely small amount of metals such as Ag compared to the active metal method, and exhibiting superior bonding strength. Printed circuit boards are repeatedly exposed to heat due to the application of voltage or placed in a thermal shock environment due to changes in the surrounding environment. At this time, thermal stress occurs because the thermal expansion coefficients of the ceramic substrate and the copper sheet are different, and delamination is prone to occur due to repeated thermal shock. Accordingly, there is a need to develop printed circuit boards with strong interlayer bonding strength to prevent delamination even in thermal shock environments. FIG. 1 is a cross-sectional view showing a ceramic substrate, a deposited layer, and a metal sheet according to one embodiment of the present invention. FIG. 2 is a cross-sectional view showing a ceramic substrate, a bonding layer, and a metal sheet according to one embodiment of the present invention. FIG. 3 is a scanning electron microscope (SEM) image of a cross-section of a ceramic substrate and a deposited layer according to one embodiment of the present invention. FIG. 4 is a scanning electron microscope (SEM) image of a cross-section of a ceramic substrate, a bonding layer, and a metal sheet according to one embodiment of the present invention. Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification. Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings. Furthermore, when a part such as a layer, membrane, region, or plate is said to be "on" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Also, saying that a part is "on" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "on" or "on" facing the opposite direction of gravity. Furthermore, throughout the specific