Multi-layer board

Abstract

The multilayer board includes a plurality of laminated boards. Each of the laminated boards includes a liquid crystal polymer substrate and a metal layer. Each of the liquid crystal polymer substrates has a melting point. When the number of the liquid crystal polymer substrates is odd, the laminated board includes a first intermediate substrate located at the center. The first melting point of the first intermediate substrate is the lowest among the melting points, and the melting points increase away from the first intermediate substrate. When the number of the liquid crystal polymer substrates is even, the laminated board includes second and third intermediate substrates located at the center. The second melting point of the second intermediate substrate or the third melting point of the third intermediate substrate is the lowest among the melting points of the liquid crystal polymer substrates. The second melting point and the third melting point are substantially the same. The melting points increase away from the second and third intermediate substrates. When the laminated board is hot-pressed to form the multilayer board, the deformation of each layer of the liquid crystal polymer substrates is similar due to the different melting points. Thus, the multilayer board has good flatness, high yield, and good electrical performance.

Description

Technical Field

[0001] This disclosure relates to a multilayer board, and more particularly to a multilayer board containing multiple liquid crystal polymer substrates with different melting points. Background Technology

[0002] Modern mobile devices, such as smartphones, tablets, and laptops, use central processing units (CPUs) with clock rates mostly above gigahertz (GHz). Therefore, these devices require high-frequency circuitry to meet the demands of these CPUs. Furthermore, to satisfy the requirements of high-frequency circuitry, manufacturers must minimize the adverse effects of RC delay.

[0003] Liquid crystal polymers (LCPs) possess excellent low moisture absorption, heat resistance, chemical resistance, and dielectric properties, making them suitable as substrates for high-frequency circuits or high-speed transmission lines. Multilayer boards consist of multiple dielectric layers. During hot-pressing, these dielectric layers are at varying distances from the heat source, leading to uneven heating and poor bonding in the multilayer board. Therefore, a new type of multilayer board is needed to overcome these problems. Summary of the Invention

[0004] This disclosure provides a multilayer board comprising multiple laminated plates (laminate; laminated plate; laminated panel) stacked from bottom to top. Each of these laminated plates is a single-sided or double-sided panel. Each of these laminated plates includes a liquid crystal polymer substrate and at least one metal layer. Each of these liquid crystal polymer substrates has a melting point. When the number of these liquid crystal polymer substrates is an odd number equal to or greater than 3, these liquid crystal polymer substrates include a first intermediate substrate located at the center, the first intermediate substrate having the lowest first melting point among the melting points of these liquid crystal polymer substrates, and the melting points of these liquid crystal polymer substrates increasing away from the first intermediate substrate. When the number of these liquid crystal polymer substrates is an even number equal to or greater than 4, these liquid crystal polymer substrates include a second intermediate substrate and a third intermediate substrate located at the center, the second melting point of the second intermediate substrate or the third melting point of the third intermediate substrate having the lowest second melting point or the third melting point of the third intermediate substrate being substantially the same among the melting points of these liquid crystal polymer substrates, and the melting points of these liquid crystal polymer substrates increasing away from the second and third intermediate substrates.

[0005] In some embodiments, these laminates include a first laminate, a second laminate, and a third laminate. The first laminate includes a first liquid crystal polymer substrate and at least one first metal layer, the first liquid crystal polymer substrate having a fourth melting point. The second laminate includes a second liquid crystal polymer substrate and at least one second metal layer, the second liquid crystal polymer substrate having a fifth melting point. The third laminate includes a third liquid crystal polymer substrate and at least one third metal layer, the third liquid crystal polymer substrate having a sixth melting point. The second laminate is disposed between the first laminate and the third laminate. The fourth and sixth melting points are substantially the same and higher than the fifth melting point.

[0006] In some implementations, the fourth and sixth melting points are 33°C to 57°C higher than the fifth melting point.

[0007] In some embodiments, the multilayer board further includes a fourth and a fifth laminate. The fourth laminate includes a fourth liquid crystal polymer substrate and at least one fourth metal layer, the fourth liquid crystal polymer substrate having a seventh melting point. The fifth laminate includes a fifth liquid crystal polymer substrate and at least one fifth metal layer, the fifth liquid crystal polymer substrate having an eighth melting point. The fourth laminate is disposed on the third laminate, and the fifth laminate is disposed below the first laminate. The seventh and eighth melting points are substantially the same, the seventh melting point being higher than the sixth melting point, and the eighth melting point being higher than the fourth melting point.

[0008] In some embodiments, the fourth and sixth melting points are 33°C to 47°C higher than the fifth melting point, and the seventh and eighth melting points are 43°C to 57°C higher than the fifth melting point.

[0009] In some embodiments, these laminates include a first laminate, a second laminate, a third laminate, and a fourth laminate. The first laminate includes a first liquid crystal polymer substrate and at least a first metal layer, the first liquid crystal polymer substrate having a fourth melting point. The second laminate includes a second liquid crystal polymer substrate and at least a second metal layer, the second liquid crystal polymer substrate having a fifth melting point. The third laminate includes a third liquid crystal polymer substrate and at least a third metal layer, the third liquid crystal polymer substrate having a sixth melting point. The fourth laminate includes a fourth liquid crystal polymer substrate and at least a fourth metal layer, the fourth liquid crystal polymer substrate having a seventh melting point. The first to fourth laminates are stacked sequentially from bottom to top. The fifth and sixth melting points are substantially the same, the fourth and seventh melting points are substantially the same, and the fourth and seventh melting points are higher than the fifth or sixth melting point.

[0010] In some implementations, the fourth and seventh melting points are 33°C to 57°C higher than the fifth or sixth melting point.

[0011] In some embodiments, the melting point of the liquid crystal polymer substrate closest to the first intermediate substrate is 33°C to 57°C higher than the first melting point, and the melting point of the liquid crystal polymer substrate closest to the second and third intermediate substrates is 33°C to 57°C higher than the second or third melting point.

[0012] In some embodiments, these liquid crystal polymer substrates comprise the same liquid crystal polymer.

[0013] In some embodiments, in the multilayer boards of any of the foregoing embodiments, these liquid crystal polymer substrates include thermotropic liquid crystal polymers, thermoplastic liquid crystal polymers, or combinations thereof.

[0014] It should be understood that the foregoing general description and the following specific description are merely exemplary and explanatory, and are intended to provide further explanation of the claimed content of this disclosure. Attached Figure Description

[0015] The contents of this disclosure, as well as other states, features, and advantages, will be more clearly understood with reference to the description and accompanying drawings, wherein:

[0016] Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 7 , Figure 8 , Figure 9 , Figure 10 and Figure 12 This is a schematic diagram of a multilayer board according to various embodiments of the present disclosure;

[0017] Figure 4 , Figure 6 and Figure 11 This is a schematic diagram of a stack for forming a multilayer board according to various embodiments of the present disclosure.

[0018] [Symbol Explanation]

[0019] 100, 200, 300, 500, 700, 800, 900, 1000, 1200: Multilayer boards

[0020] 400, 600, 1100: Stacked

[0021] 110, 210, 310, 310', 510, 510', 710, 810, 910, 1010, 1210: First laminated plate

[0022] 120, 220, 320, 320', 520, 520', 720, 820, 920, 1020, 1220: Second laminated plate

[0023] 130, 230, 330, 330', 530, 530', 730, 830, 930, 1030, 1230: Third laminated plate

[0024] 240, 540, 540', 740, 840, 940, 1240: Fourth laminated plate

[0025] 310A, 510A, 710A, 810A, 910A, 1010A, 1210A: First liquid crystal polymer substrate

[0026] 310B, 310B', 510B, 510B', 710B, 810B, 910B, 1010B, 1010B', 1210B: First metal layer

[0027] 320A, 520A, 720A, 820A, 920A, 1020A, 1220A: Second liquid crystal polymer substrate

[0028] 320B, 320B', 520B, 520B', 720B, 820B, 920B, 1220B: Second metal layer

[0029] 330A, 530A, 730A, 830A, 930A, 1030A, 1230A: Third liquid crystal polymer substrate

[0030] 330B, 330B', 530B, 530B', 730B, 830B, 930B, 1030B, 1030B', 1230B: Third metal layer

[0031] 540A, 740A, 840A, 940A, 1240A: Fourth Liquid Crystal Polymer Substrate

[0032] 540B, 540B', 740B, 840B, 940B: Fourth metal layer

[0033] 750, 850, 950, 1250: Fifth laminated plate

[0034] 750A, 850A, 950A, 1250A: Fifth Liquid Crystal Polymer Substrate

[0035] 750B, 850B, 950B, 1250B: Fifth metal layer

[0036] 860, 960, 1260: Sixth laminated plate

[0037] 860A, 960A, 1260A: The sixth liquid crystal polymer substrate

[0038] 860B, 960B, 1260B: Sixth metal layer

[0039] 870, 970, 1270: Seventh laminated plate

[0040] 870A, 970A, 1270A: Seventh Liquid Crystal Polymer Substrate

[0041] 870B, 970B, 1270B: Seventh metal layer

[0042] 980: Eighth laminated board

[0043] 980A: The eighth liquid crystal polymer substrate

[0044] 980B: Eighth Metal Layer

[0045] 990: Ninth laminated plate

[0046] 990A: Ninth Liquid Crystal Polymer Substrate

[0047] 990B: Ninth Metal Layer

[0048] 1020B, 1020B': Second lower metal layer

[0049] 1020C, 1020C': Second upper metal layer

[0050] 1240B: Fourth lower metal layer

[0051] 1240C: Fourth upper metal layer

[0052] 9900: Tenth laminated plate

[0053] 9900A: Tenth Liquid Crystal Polymer Substrate

[0054] 9900B: Tenth Metal Layer

[0055] 9910: Eleventh laminated plate

[0056] 9910A: Eleventh Liquid Crystal Polymer Substrate

[0057] 9910B: Eleventh Metal Layer

[0058] 9920: Twelfth laminate

[0059] 9920A: Twelfth Liquid Crystal Polymer Substrate

[0060] 9920B: Twelfth Metal Layer

[0061] 9930: Thirteenth Laminated Plate

[0062] 9930A: Thirteenth Liquid Crystal Polymer Substrate

[0063] 9930B: Thirteenth Metal Layer Detailed Implementation

[0064] The following describes several embodiments of this disclosure with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit the scope of this disclosure. That is, these practical details are not essential in some embodiments of this disclosure. Furthermore, for the sake of simplicity, some known and conventional structures and elements will be shown in the drawings in a simple schematic manner.

[0065] In this disclosure, the use of terms such as first, second, and third, etc., to describe various elements, components, regions, layers, and / or blocks is understandable. However, these elements, components, regions, layers, and / or blocks should not be limited by these terms. These terms are limited to identifying individual elements, components, regions, layers, and / or blocks only. Therefore, a first element, component, region, layer, and / or block in the following text may also be referred to as a second element, component, region, layer, and / or block without departing from the intent of this disclosure.

[0066] In this disclosure, the laminate can be a single-sided or double-sided board. A single-sided board includes a liquid crystal polymer substrate and a metal layer located on the surface of the liquid crystal polymer substrate. A double-sided board includes a liquid crystal polymer substrate and two metal layers located on the upper and lower surfaces of the liquid crystal polymer substrate, respectively. The aforementioned metal layers can be unetched metal foil or metal circuits formed by etched metal foil. When the metal layers are metal circuits, the laminate can also be referred to as a circuit board.

[0067] This disclosure provides a multilayer board comprising multiple laminated boards stacked from bottom to top. Each of these laminated boards is a single-sided or double-sided board. Each of these laminated boards includes a liquid crystal polymer substrate and at least one metal layer. Each of these liquid crystal polymer substrates has a melting point. The number of laminated boards is odd or even. When the number of liquid crystal polymer substrates is an odd number equal to or greater than 3, the liquid crystal polymer substrates include a first intermediate substrate located at the center, the first intermediate substrate having the lowest melting point among the melting points of these liquid crystal polymer substrates, and the melting points of these liquid crystal polymer substrates increasing in the direction away from the first intermediate substrate. In other words, the melting point of the liquid crystal polymer substrates between the first intermediate substrate and the upper surface of the multilayer board increases from bottom to top, and the melting point of the liquid crystal polymer substrates between the first intermediate substrate and the lower surface of the multilayer board increases from top to bottom. When the number of these liquid crystal polymer substrates is an even number equal to or greater than 4, these liquid crystal polymer substrates include a second intermediate substrate and a third intermediate substrate located at the center, with the second intermediate substrate situated on top of the third intermediate substrate. The second melting point of the second intermediate substrate or the third melting point of the third intermediate substrate is the lowest among the melting points of these liquid crystal polymer substrates, and the second and third melting points are substantially the same. The melting points of these liquid crystal polymer substrates increase in the direction away from the second and third intermediate substrates. In other words, the melting point of the liquid crystal polymer substrates between the second intermediate substrate and the upper surface of the multilayer increases from bottom to top, and the melting point of the liquid crystal polymer substrates between the third intermediate substrate and the lower surface of the multilayer increases from top to bottom. In some embodiments, the melting point of the aforementioned intermediate substrates is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C. In some embodiments, the melting point of the liquid crystal polymer substrates adjacent to the aforementioned intermediate substrates is 33°C to 57°C higher than the melting point of the intermediate substrates. For example: 33, 36, 39, 42, 45, 48, 51, 54 or 57℃.

[0068] In some embodiments, the liquid crystal polymer substrates each comprise the same type of liquid crystal polymer. In some embodiments, the liquid crystal polymer substrates each comprise different types of liquid crystal polymers. In some embodiments, the liquid crystal polymer substrates comprise thermotropic liquid crystal polymers, thermoplastic liquid crystal polymers, or combinations thereof.

[0069] A method for manufacturing a multilayer board includes hot-pressing (e.g., a single hot-pressing) a stack containing the aforementioned multilayer boards. During the manufacturing of the multilayer board, a heat source is placed on the upper and lower surfaces of the stack. In some embodiments, the melting point of the liquid crystal polymer substrate closest to the heat source is T. m The hot pressing temperature is T. m -30°C~T m°C. In a multilayer laminate, the laminar flow plates near the top and bottom surfaces receive more heat, while those farther away receive less, resulting in uneven heating. If the liquid crystal polymer substrates within these laminar flow plates, which support the metal layers, all contain liquid crystal polymers with the same melting point, the laminate may experience poor bonding due to uneven heating. However, in the multilayer laminate disclosed herein, the liquid crystal polymer substrates have different melting points. The middle substrate has the lowest melting point, while the outermost (top and bottom) substrates have the highest melting point, with the melting points of the remaining substrates increasing outwards (upwards and downwards). Therefore, during hot pressing, the deformation of each liquid crystal polymer substrate is similar, resulting in a multilayer laminate with good flatness and high yield. Furthermore, liquid crystal polymers have low water absorption, dielectric constant, loss coefficient, and coefficient of thermal expansion, as well as excellent dimensional stability, electrical properties, gas barrier properties, and thermal conductivity. Therefore, compared with general dielectric materials, they are more suitable as insulating substrate materials for multilayer boards.

[0070] The following will illustrate various embodiments of the multilayer board disclosed herein with reference to the accompanying drawings. The number of laminates in the multilayer board disclosed herein can be adjusted arbitrarily according to design requirements, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, but is not limited thereto. Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 7 , Figure 8 , Figure 9 , Figure 10 and Figure 12 This is a schematic diagram of a multilayer board according to various embodiments of the present disclosure. Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 7 , Figure 8 , Figure 9 , Figure 10 and Figure 12 The embodiments of multilayer boards containing 3, 4, 3, 4, 5, 7, 13, 3, and 7 layers of laminated boards are shown respectively.

[0071] like Figure 1As shown, the multilayer board 100 includes three laminated boards: a first laminated board 110, a second laminated board 120, and a third laminated board 130. The number of laminated boards can be adjusted arbitrarily and is not limited to this. The first laminated board 110, the second laminated board 120, and the third laminated board 130 are each single-sided or double-sided. The first laminated board 110, the second laminated board 120, and the third laminated board 130 respectively include a first liquid crystal polymer substrate having a first melting point, a second liquid crystal polymer substrate having a second melting point, and a third liquid crystal polymer substrate having a third melting point. The second liquid crystal polymer substrate is the middle substrate located in the most central position. Among all melting points, the second melting point is the lowest, and the first melting point, the second melting point, and the third melting point increase in the direction away from the second liquid crystal polymer substrate. In other words, the first melting point and the third melting point are higher than the second melting point. In some embodiments, the first melting point and the third melting point are substantially the same. Since the distribution of the above melting points is symmetrical, during the hot pressing process to form the multilayer board 100, the deformation degrees of the first laminate 110 and the third laminate 130 are similar, thereby giving the multilayer board 100 good flatness and high yield. In some embodiments, the first melting point and the third melting point are 33°C to 57°C higher than the second melting point.

[0072] like Figure 2 As shown, the multilayer board 200 includes four laminated boards: a first laminated board 210, a second laminated board 220, a third laminated board 230, and a fourth laminated board 240. The number of laminated boards can be adjusted arbitrarily and is not limited to this. Each of the first laminated board 210, the second laminated board 220, the third laminated board 230, and the fourth laminated board 240 is either a single-sided board or a double-sided board. The first laminated board 210, the second laminated board 220, the third laminated board 230, and the fourth laminated board 240 respectively include a first liquid crystal polymer substrate having a first melting point, a second liquid crystal polymer substrate having a second melting point, a third liquid crystal polymer substrate having a third melting point, and a fourth liquid crystal polymer substrate having a fourth melting point. The second and third liquid crystal polymer substrates are respectively the first and second intermediate substrates located in the middle position. Among all melting points, the second or third melting point is the lowest. The second and third melting points are substantially the same, and the first, second, third, and fourth melting points increase in the direction away from the second and third liquid crystal polymer substrates. In other words, the first and fourth melting points are higher than the second or third melting point. In some embodiments, the first and fourth melting points are substantially the same. Since the distribution of the above melting points is symmetrical, during the hot pressing process to form the multilayer board 200, the deformation degrees of the first laminate 210 and the fourth laminate 240 are similar, and the deformation degrees of the second laminate 220 and the third laminate 230 are similar, thereby giving the multilayer board 200 good flatness and high yield. In some embodiments, the first and fourth melting points are 33°C to 57°C higher than the second or third melting point.

[0073] Please refer to the following at the same time Figure 1 and Figure 3 , Figure 3 Multilayer board 300 Figure 1 One embodiment of the multilayer board 100. The multilayer board 300 includes three single-sided boards, namely a first laminate 310, a second laminate 320, and a third laminate 330. The first laminate 310 includes a first liquid crystal polymer substrate 310A having a first melting point and a first metal layer 310B. The second laminate 320 includes a second liquid crystal polymer substrate 320A having a second melting point and a second metal layer 320B. The third laminate 330 includes a third liquid crystal polymer substrate 330A having a third melting point and a third metal layer 330B. The second laminate 320 is disposed between the first laminate 310 and the third laminate 330. The first melting point and the third melting point are higher than the second melting point. In some embodiments, the first melting point and the third melting point are substantially the same. In some embodiments, the first melting point and the third melting point are 33°C to 57°C higher than the second melting point. In some embodiments, the first metal layer 310B, the second metal layer 320B, and the third metal layer 330B may be unetched metal foils or metal circuits (not shown). Table 1 below lists the multilayer boards 300 of Examples 1 to 6. In some embodiments, M is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C.

[0074] Table 1

[0075]

[0076] In some embodiments, the thicknesses of the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A are each independently from 1µm to 2000µm, for example, 10µm, 50µm, 100µm, 300µm, 500µm, 700µm, 900µm, 1000µm, 1300µm, or 1500µm, but are not limited thereto.

[0077] In some embodiments, conductive elements (e.g., conductive vias) (not shown) may be provided within the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A to electrically connect the metal layer. In some embodiments, each of the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A comprises a different type of liquid crystal polymer. In some embodiments, each of the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A comprises the same type of liquid crystal polymer. In some embodiments, the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A comprise a thermotropic liquid crystal polymer, and the thermotropic liquid crystal polymer is, for example, a thermotropic liquid crystal polymer resin. Thermotropic liquid crystal polymer resins include high-heat-resistant type I liquid crystal polymer resins, medium-heat-resistant type II liquid crystal polymer resins, and low-heat-resistant type III liquid crystal polymer resins.

[0078] In some embodiments, the high-heat-resistant liquid crystal polymer resin comprises a liquid crystal polymer resin polymerized from p-hydroxybenzoic acid (HBA), terephthalic acid (TA), and 4,4'-dioxydiphenol (DODP). In other embodiments, the medium-heat-resistant liquid crystal polymer resin comprises a liquid crystal polymer resin polymerized from p-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA). In yet another embodiment, the low-heat-resistant liquid crystal polymer resin comprises a liquid crystal polymer resin polymerized from polyethylene terephthalate (PET) and p-hydroxybenzoic acid (HBA).

[0079] In some embodiments, this disclosure provides a method for adjusting the melting point of a liquid crystal polymer substrate. The liquid crystal polymer substrate includes a thermotropic liquid crystal polymer resin. The melting point of the liquid crystal polymer before heating is a melting point Tm1. In some embodiments, the melting point Tm1 is between 200°C and 400°C, for example, 250, 270, 280, 290, 300, or 350°C. Step A: The liquid crystal polymer is heated to a first temperature and maintained at the first temperature for a first time. The first temperature is less than or equal to the first melting point of the liquid crystal polymer. In some embodiments, the difference between the first temperature and the melting point Tm1 is less than or equal to 100°C, for example, 20, 40, 60, or 80°C. In some embodiments, the heating rate is 0.1°C / min to 40°C / min, for example, 0.2, 0.5, 1, 5, 10, 20, 30, or 40°C / min. If the heating rate is too slow, the process time may be too long, increasing manufacturing costs; if the heating rate is too fast, the liquid crystal polymer may be heated unevenly. In some embodiments, the first time is from 1 minute to 48 hours, for example, 1, 5, 20, or 30 minutes or 1, 5, 10, 20, 30, 40, or 48 hours. Step B: Cool the liquid crystal polymer to a second temperature to form a modified liquid crystal polymer, wherein the second temperature is lower than the first temperature. This modified liquid crystal polymer has a melting point Tm2, ​​which is greater than the melting point Tm1 of the liquid crystal polymer. In some embodiments, the second temperature is greater than or equal to room temperature, for example, 30, 40, 50, or 60°C. In some embodiments, the second temperature is lower than 100°C. Heating the liquid crystal polymer to the first temperature can cause its structure to partially recombine, so when the liquid crystal polymer is cooled to the second temperature, the crystal arrangement, size, and shape of the liquid crystal polymer will change, thereby increasing the melting point of the liquid crystal polymer. Steps A and B can be repeated multiple times to increase the melting point of the liquid crystal polymer, with each heating temperature being 20°C-50°C higher than the previous heating temperature. Liquid crystal polymer substrates with different melting points can be fabricated using the above method. The liquid crystal polymer substrate may include the same or different liquid crystal polymers.

[0080] In some embodiments, the first, second, and third liquid crystal polymer substrates 310A, 320A, and 330A comprise thermoplastic liquid crystal polymers. In some embodiments, the thermoplastic liquid crystal polymer is polymerized from a reactant selected from the group consisting of (1) aromatic or aliphatic dicarboxylic acids, (2) aromatic hydroxycarboxylic acids, (3) aromatic or aliphatic dihydroxy compounds, and (4) aromatic diamines, aromatic hydroxyamines, or aromatic aminocarboxylic acids.

[0081] (1) Aromatic or aliphatic dicarboxylic acids, including those composed of

[0082] , , , , and and (2) Aromatic hydroxycarboxylic acids include those composed of (where n is an integer from 2 to 12). (X can be a hydrogen atom or a halogen atom, a lower alkyl group or a phenyl group) , and The group consisting of (3) aromatic or aliphatic dihydroxy compounds including those composed of (X can be a hydrogen atom or a halogen atom, a lower alkyl group or a phenyl group) , , (Y can be O, CH2, or S, etc.) , and (n is an integer from 2 to 12) group. (4) Aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids include those composed of , and The group formed by them.

[0083] This disclosure provides a method for adjusting the melting point of a liquid crystal polymer substrate. The liquid crystal polymer substrate includes a thermoplastic liquid crystal polymer. The melting point of the liquid crystal polymer substrate before heating is a melting point Tm1. By heating a laminated plate at a specific temperature for a duration between 1 hour and 24 hours, where the specific temperature is greater than or equal to Tm1-30°C and less than Tm1°C, the melting point of the liquid crystal polymer substrate in the laminated plate can be increased. In some embodiments, the heating time is 1, 5, 10, 15, 20, or 24 hours. By heating the laminated plate for a longer period, the melting point of the liquid crystal polymer substrate can be increased. As the heating time increases, the melting point of the liquid crystal polymer substrate increases accordingly. Liquid crystal polymer substrates with different melting points can be fabricated using the above method. The liquid crystal polymer substrate may include the same or different liquid crystal polymers.

[0084] In some embodiments, the first, second, and third metal layers 310B, 320B, and 330B are each independently a copper substrate, aluminum substrate, nickel substrate, palladium substrate, or tin substrate, but are not limited thereto. For example, the metal layer may be copper foil. In some embodiments, the thickness of the first, second, and third metal layers 310B, 320B, and 330B is each independently from 100 μm to 500 μm, for example 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, or 450 μm, but is not limited thereto. All embodiments of the liquid crystal polymer substrate and metal layers in this disclosure can refer to the above description. Figure 3 The implementation method is described below, so it will not be repeated hereafter.

[0085] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a stack 400 for forming a multilayer board according to various embodiments of this disclosure. For example... Figure 4 As shown, before hot pressing the laminate 400, the first metal layer 310B', second metal layer 320B', and third metal layer 330B' of the first laminate 310', second laminate 320', and third laminate 330' are patterned metal lines. These laminates can also be referred to as circuit boards. In some embodiments, after hot pressing, the first liquid crystal polymer substrate 310A and the second liquid crystal polymer substrate 320A will be in direct contact and will cover the sidewall of the first metal layer 310B' (not shown), and the second liquid crystal polymer substrate 320A and the third liquid crystal polymer substrate 330A will be in direct contact and will cover the sidewall of the second metal layer 320B' (not shown).

[0086] Please refer to the following at the same time Figure 2 and Figure 5 , Figure 5 500 multilayer boards Figure 2 One embodiment of a multilayer board 200. The multilayer board 500 includes four single-sided boards. The multilayer board 500 includes a first laminate 510, a second laminate 520, a third laminate 530, and a fourth laminate 540. The first laminate 510 includes a first liquid crystal polymer substrate 510A having a first melting point and a first metal layer 510B. The second laminate 520 includes a second liquid crystal polymer substrate 520A having a second melting point and a second metal layer 520B. The third laminate 530 includes a third liquid crystal polymer substrate 530A having a third melting point and a third metal layer 530B. The fourth laminate 540 includes a fourth liquid crystal polymer substrate 540A having a fourth melting point and a fourth metal layer 540B. The first laminate 510 to the fourth laminate 540 are stacked sequentially from bottom to top. The second melting point and the third melting point are substantially the same, the first melting point and the fourth melting point are substantially the same, and the first melting point and the fourth melting point are higher than the second melting point or the third melting point. In some embodiments, the first melting point and the fourth melting point are 33°C to 57°C higher than the second melting point or the third melting point. In some embodiments, the first metal layer 510B, the second metal layer 520B, the third metal layer 530B, and the fourth metal layer 540B may be unetched metal foils or metal circuits (not shown).

[0087] Please refer to Figure 6 , Figure 6 This is a schematic diagram of a stack 600 for forming a multilayer board according to various embodiments of this disclosure. For example... Figure 6As shown, before hot pressing the stack 600, the first metal layer 510B', second metal layer 520B', third metal layer 530B', and fourth metal layer 540B' of the first stack 510', second stack 520', third stack 530', and fourth stack 540' are patterned metal lines. These stacks can also be referred to as circuit boards. In some embodiments, after hot pressing, these liquid crystal polymer substrates are in direct contact with each other and cover the sidewalls (not shown) of the first, second, and third metal layers 510B', 520B', and 530B'. An embodiment of the hot-pressed stack 600 can be found in [reference needed]. Figure 4 The implementation method.

[0088] like Figure 7 As shown, the multilayer board 700 includes five single-sided panels. The multilayer board 700 includes a first laminate 710, a second laminate 720, a third laminate 730, a fourth laminate 740, and a fifth laminate 750. The first laminate 710 includes a first liquid crystal polymer substrate 710A having a first melting point and a first metal layer 710B. The second laminate 720 includes a second liquid crystal polymer substrate 720A having a second melting point and a second metal layer 720B. The third laminate 730 includes a third liquid crystal polymer substrate 730A having a third melting point and a third metal layer 730B. The fourth laminate 740 includes a fourth liquid crystal polymer substrate 740A having a fourth melting point and a fourth metal layer 740B. The fifth laminate 750 includes a fifth liquid crystal polymer substrate 750A having a fifth melting point and a fifth metal layer 750B. The first laminate 710 to the fifth laminate 750 are stacked sequentially from bottom to top. The third liquid crystal polymer substrate 730A is the intermediate substrate located at the very center. Of all melting points, the third melting point is the lowest, and the first, second, third, fourth, and fifth melting points increase in the direction away from the third liquid crystal polymer substrate 730A. In other words, the second and fourth melting points are higher than the third melting point, the first melting point is higher than the second melting point, and the fifth melting point is higher than the fourth melting point. In some embodiments, the second and fourth melting points are substantially the same, and the first and fifth melting points are substantially the same. In some embodiments, the second and fourth melting points are 33°C to 47°C higher than the third melting point, and the first and fifth melting points are 43°C to 57°C higher than the third melting point. Examples 7 to 10 are listed in Table 2 below. In some embodiments, M is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C.

[0089] Table 2

[0090]

[0091] like Figure 8As shown, the multilayer board 800 includes seven single-sided panels. The multilayer board 800 includes first, second, third, fourth, fifth, sixth, and seventh laminates 810, 820, 830, 840, 850, 860, and 870. These laminates include first, second, third, fourth, fifth, sixth, and seventh liquid crystal polymer substrates 810A, 820A, 830A, 840A, 850A, 860A, and 870A, and first, second, third, fourth, fifth, sixth, and seventh metal layers 810B, 820B, 830B, 840B, 850B, 860B, and 870B. The liquid crystal polymer substrates each have a first, second, third, fourth, fifth, sixth, and seventh melting point. The first laminate 810 to the seventh laminate 870 are stacked sequentially from bottom to top. The fourth liquid crystal polymer substrate 840A is the intermediate substrate located in the middle position. Of all the melting points, the fourth melting point is the lowest, and the first, second, third, fourth, fifth, sixth, and seventh melting points increase in the direction away from the fourth liquid crystal polymer substrate 840A. In other words, the third and fifth melting points are higher than the fourth melting point, the second melting point is higher than the third melting point, the first melting point is higher than the second melting point, the sixth melting point is higher than the fifth melting point, and the seventh melting point is higher than the sixth melting point. In some embodiments, the third and fifth melting points are substantially the same, the second and sixth melting points are substantially the same, and the first and seventh melting points are substantially the same. Table 3 below lists Example 11. In some embodiments, M is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C.

[0092] Table 3

[0093]

[0094] like Figure 9As shown, the multilayer board 900 includes 13 single-sided panels. The multilayer board 900 includes first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth and thirteenth laminated boards 910, 920, 930, 940, 950, 960, 970, 980, 990, 9900, 9910, 9920 and 9930. The aforementioned laminate includes first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, and thirteenth liquid crystal polymer substrates 910A, 920A, 930A, 940A, 950A, 960A, 970A, 980A, 990A, 9900A, 9910A, 9920A, and 9930A, and first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, and thirteenth metal layers 910B, 920B, 930B, 940B, 950B, 960B, 970B, 980B, 990B, 9900B, 9910B, 9920B, and 9930B, respectively. The aforementioned liquid crystal polymer substrates each have a melting point of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, and thirteenth, respectively. The first laminate 910 to the thirteenth laminate 9930 are stacked sequentially from bottom to top. The seventh liquid crystal polymer substrate 970A is the intermediate substrate located in the middle position. Among all melting points, the seventh melting point is the lowest, and all melting points increase in the direction away from the seventh liquid crystal polymer substrate 970A. Specifically, the melting point increases from the seventh melting point to the thirteenth melting point, and from the seventh melting point to the first melting point. Example 12 is listed in Table 4 below. In some embodiments, M is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C.

[0095] Table 4

[0096]

[0097] Please refer to the following at the same time Figure 2 and Figure 10 , Figure 10 1000 multilayer boards Figure 1One embodiment of the multilayer board 1000. The multilayer board 1000 includes two single-sided panels and one double-sided panel. The multilayer board 1000 includes a first laminate 1010, a second laminate 1020, and a third laminate 1030. The first laminate 1010 includes a first liquid crystal polymer substrate 1010A having a first melting point and a first metal layer 1010B. The second laminate 1020 includes a second liquid crystal polymer substrate 1020A having a second melting point, a second lower metal layer 1020B, and a second upper metal layer 1020C. The third laminate 1030 includes a third liquid crystal polymer substrate 1030A having a third melting point and a third metal layer 1030B. The second laminate 1020 is disposed between the first laminate 1010 and the third laminate 1030. The first melting point and the third melting point are higher than the second melting point. In some embodiments, the first melting point and the third melting point are substantially the same. In some embodiments, the first and third melting points are 33°C to 57°C higher than the second melting point. In some embodiments, the metal layer may be an unetched metal foil or a metal circuit (not shown).

[0098] Please refer to Figure 11 , Figure 11 This is a schematic diagram of a stack 1100 for forming a multilayer board according to various embodiments of this disclosure. For example... Figure 11 As shown, before hot pressing the stack 1100, the first metal layer 1010B', the second lower metal layer 1020B', the second upper metal layer 1020C', and the third metal layer 1030B' of the first stack 1010', the second stack 1020', and the third stack 1030' are patterned metal lines. These stacks can also be referred to as circuit boards. In some embodiments, after hot pressing, these liquid crystal polymer substrates are in direct contact with each other and cover the sidewalls (not shown) of the second lower metal layer 1020B' and the second upper metal layer 1020C'. An embodiment of the hot-pressed stack 1100 can be found in [reference needed]. Figure 4 The implementation method.

[0099] like Figure 12As shown, the multilayer board 1200 includes six single-sided panels and one double-sided panel. The multilayer board 1200 includes first, second, third, fourth, fifth, sixth, and seventh laminates 1210, 1220, 1230, 1240, 1250, 1260, and 1270. The aforementioned laminates include first, second, third, fourth, fifth, sixth, and seventh liquid crystal polymer substrates 1210A, 1220A, 1230A, 1240A, 1250A, 1260A, and 1270A. The aforementioned laminates also include a first metal layer 1210B, a second metal layer 1220B, a third metal layer 1230B, a fourth lower metal layer 1240B, a fourth upper metal layer 1240C, a fifth metal layer 1250B, a sixth metal layer 1260B, and a seventh metal layer 1270B. The aforementioned liquid crystal polymer substrates have first, second, third, fourth, fifth, sixth, and seventh melting points, respectively. The first laminate 1210 to the seventh laminate 1270 are stacked sequentially from bottom to top. The fourth liquid crystal polymer substrate 1240A is the intermediate substrate located in the middle position. Of all the melting points, the fourth melting point is the lowest, and all melting points increase in the direction away from the fourth liquid crystal polymer substrate 1240A. Specifically, the fourth melting point increases towards the seventh melting point, and the fourth melting point increases towards the first melting point. Example 13 is listed in Table 5 below. In some embodiments, M is 283°C to 287°C, for example, 283, 284, 285, 286, or 287°C.

[0100] Table 5

[0101]

[0102] This disclosure provides a multilayer board containing multiple laminated layers. These laminated layers include multiple liquid crystal polymer substrates with different melting points. The liquid crystal polymer substrate located in the middle has the lowest melting point, the liquid crystal polymer substrate located on the outermost side has the highest melting point, and the melting points of the remaining liquid crystal polymer substrates increase outwards. When the above-mentioned laminated layers are hot-pressed to form a multilayer board, due to the different melting points, the deformation degree of each liquid crystal polymer substrate is similar, thereby giving the multilayer board good flatness and high yield, and thus the multilayer board has good electrical performance.

[0103] Although this disclosure has been described in considerable detail with reference to certain embodiments, other embodiments may also be possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments included herein.

[0104] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of this disclosure without departing from its scope or spirit. In view of the foregoing, this disclosure is intended to cover any modifications and variations of this disclosure that fall within the scope of the appended claims.

Claims

1. A multilayer board, characterized in that, include: A multilayer laminate, wherein the laminates are stacked from bottom to top, each laminate being a single-sided or double-sided laminate, each laminate including a liquid crystal polymer substrate and at least one metal layer, each liquid crystal polymer substrate having a melting point. The number of liquid crystal polymer substrates is an odd number greater than 3. The liquid crystal polymer substrates include a first intermediate substrate located at the very center. The melting point of the first intermediate substrate is the lowest among the melting points of the liquid crystal polymer substrates. The melting points of the liquid crystal polymer substrates increase in the direction away from the first intermediate substrate. The laminates include: A first laminate includes a first liquid crystal polymer substrate and at least a first metal layer, wherein the first liquid crystal polymer substrate has a first melting point; A second laminate includes a second liquid crystal polymer substrate and at least a second metal layer, wherein the second liquid crystal polymer substrate has a second melting point; A third laminate includes a third liquid crystal polymer substrate and at least a third metal layer, wherein the third liquid crystal polymer substrate has a third melting point. A fourth laminate, comprising a fourth liquid crystal polymer substrate and at least a fourth metal layer, wherein the fourth liquid crystal polymer substrate has a fourth melting point; and A fifth laminate includes a fifth liquid crystal polymer substrate and at least a fifth metal layer, wherein the fifth liquid crystal polymer substrate has a fifth melting point. The first to the fifth laminated plates are stacked sequentially from bottom to top. The second and fourth melting points are substantially the same and higher than the third melting point. The first and fifth melting points are substantially the same, the first melting point is higher than the second melting point, and the fifth melting point is higher than the fourth melting point. Or The number of liquid crystal polymer substrates is 6. The liquid crystal polymer substrates include a second intermediate substrate and a third intermediate substrate located at the center. The second intermediate substrate is located on the third intermediate substrate. The melting point of the second intermediate substrate or the melting point of the third intermediate substrate is the lowest among the melting points of the liquid crystal polymer substrates. The melting point of the second intermediate substrate is substantially the same as that of the third intermediate substrate. The melting points of the liquid crystal polymer substrates increase in the direction away from the second intermediate substrate and the third intermediate substrate. The melting point of the liquid crystal polymer substrate closest to the second intermediate substrate is 33°C to 57°C higher than that of the second intermediate substrate. The melting points of the liquid crystal polymer substrates between the second intermediate substrate and an upper surface of the multilayer board increase from bottom to top.

2. The multilayer board according to claim 1, characterized in that, The second and fourth melting points are 33°C to 47°C higher than the third melting point.

3. The multilayer board according to claim 1, characterized in that, The first melting point and the fifth melting point are 43°C to 57°C higher than the third melting point.

4. The multilayer board according to claim 1, characterized in that, The third melting point is 283℃~287℃.

5. The multilayer board according to claim 1, characterized in that, The second melting point and the fourth melting point are 33°C to 47°C higher than the fourth melting point, and the first melting point and the fifth melting point are 43°C to 57°C higher than the third melting point.

6. The multilayer board according to claim 1, characterized in that, The melting point of the second intermediate substrate and the melting point of the third intermediate substrate are 283°C to 287°C.

7. The multilayer board according to claim 1, characterized in that, The melting point of the liquid crystal polymer substrate closest to the second intermediate substrate is 42°C to 57°C higher than the melting point of the second intermediate substrate.

8. The multilayer board according to claim 1, characterized in that, The melting point of the liquid crystal polymer substrate closest to the third intermediate substrate is 33°C to 57°C higher than the melting point of the third intermediate substrate.

9. The multilayer board according to claim 1, characterized in that, These liquid crystal polymer substrates contain the same liquid crystal polymer.

10. The multilayer board according to any one of claims 1 to 9, characterized in that, These liquid crystal polymer substrates include thermotropic liquid crystal polymers, thermoplastic liquid crystal polymers, or combinations thereof.

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