A method for forming an adhesion buffer layer on the walls of high aspect ratio through-holes of an insulating substrate

Abstract

A method for forming an adhesion buffer layer on the walls of high aspect ratio through-holes of an insulating substrate, mainly comprises first preparing a high-power impulse magnetron sputtering system, and then arranging a plurality of metal targets in a sputtering chamber. Subsequently, an insulating substrate with a plurality of high aspect ratio through-holes is fixed in the sputtering chamber by a rotary fixture, wherein the aspect ratio of the high aspect ratio through-holes is greater than

Description

Method for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate The present invention relates to a method for forming an adhesion buffer layer, and particularly to a method for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate. With the continuous development of technology, application fields such as artificial intelligence, the Internet of Things, and the Internet of Vehicles are gradually maturing and expanding. In order to meet the increasing demand for chip performance, the semiconductor industry has been making unremitting efforts in chip miniaturization technology. In recent years, the gate length has been further reduced from 7 nanometers to 3 nanometers and even 2 nanometers. Although a series of technological breakthroughs have achieved remarkable results, the chip manufacturing technology has gradually approached the physical limit of Moore's Law. Therefore, finding new technical paths to promote the improvement of chip performance has become a major challenge faced by the semiconductor industry. With the progress of technology, the "heterogeneous integration" technology that uses 3D structure design to stack and integrate chips with different functions has emerged. This brand-new packaging method has undergone a fundamental change compared to the traditional 2D planar packaging method. By vertically stacking multiple chips, it can not only effectively improve the integration and performance of the chips, but also provide a new possibility for realizing smaller size, lower power consumption, and higher performance electronic products. In the "heterogeneous integration" technology, the interposer is a crucial structure, and metal wires are required inside it as channels for vertical signal transmission. Therefore, when realizing the above-mentioned vertical stacking structure, it is necessary to process vias on an insulating substrate (such as a glass substrate, a ceramic substrate, etc.) to facilitate subsequent metal wire filling. With the continuous advancement of technology, the aspect ratio (Aspect Ratio, AR) of the vias has also been continuously increasing (in practice, an aspect ratio greater than 4 is called a high aspect ratio), which poses higher requirements for the processing technology. After the via processing is completed, the next step is the filling process to achieve vertical signal transmission. In the traditional sputtering process, the ion movement direction is usually perpendicular to the surface of the object to be plated, and this processing method is only very effective for planar structures. However, after the aspect ratio of the vias gradually increases, it is difficult for the traditional sputtering method to completely fill the inside of the vias (insufficient ion energy). Therefore, a wet process is often required for thin film deposition to ensure sufficient metal filling of the vias. However, the wet process also has some obvious disadvantages. First, since the chemical solution has a relatively short shelf life, this means that the solution needs to be replaced frequently, and additional treatment of the waste liquid is also required, resulting in relatively high costs (or pollution problems caused by discharging waste liquid). Second, compared with the sputtering process, the wet process also has the problem of relatively low bonding strength between the thin film and the substrate, resulting in peeling and short circuit problems due to defects in the subsequent filling process, which will affect the long-term reliability and performance of the subsequent finished chips. In view of the fact that in the traditional sputtering process, the energy of the sputtered ions is relatively low, they do not have the ability to move laterally, and it is impossible to completely fill the high aspect ratio through-holes. In most cases, a wet process with higher cost and poorer bonding force is selected for processing. Accordingly, the main object of the present invention is to provide a method for forming an adhesion buffer layer on the wall of a high aspect ratio through-hole of an insulating substrate. A high-power pulsed magnetron sputtering process is carried out by using a high-power pulsed magnetron sputtering system, and an adhesion buffer layer is deposited on the inner wall of the high aspect ratio through-hole of the insulating substrate for subsequent hole filling processes to fill the high aspect ratio through-hole with a conductive metal. Compared with the traditional sputtering process, the high-power pulsed magnetron sputtering process has higher ion kinetic energy, can perform deposition processing on high aspect ratio through-holes, and has better bonding force, and the film is not easy to fall off. In addition, compared with the wet process, the high-power pulsed magnetron sputtering process is a dry process, does not require the use of chemical solutions during the process, and does not require the treatment of waste liquid, thus having the advantages of lower cost and no pollution. Accordingly, the necessary technical means adopted by the present invention to solve the problems of the prior art is to provide a method for forming an adhesion buffer layer on the wall of a high aspect ratio through-hole of an insulating substrate, comprising the following steps: First, a high-power pulsed magnetron sputtering system is prepared, and the high-power pulsed magnetron sputtering system has a sputtering chamber, and then a plurality of metal targets are arranged in the sputtering chamber. Secondly, an insulating substrate with a plurality of high aspect ratio through-holes is fixed in the sputtering chamber by a rotary fixing jig, wherein the aspect ratio of each high aspect ratio through-hole is greater than 4. Next, the sputtering chamber is evacuated so that the pressure in the sputtering chamber is lower than 5×10 -5 torr, and an argon gas is introduced into the sputtering chamber. Finally, a high-power pulsed magnetron sputtering process is carried out to deposit an adhesion buffer layer on the inner wall of the high aspect ratio through-hole for a subsequent hole filling process to fill the high aspect ratio through-hole with a conductive metal. Wherein, each of the above-mentioned metal targets is composed of at least one of copper, titanium, chromium, zirconium, tungsten, aluminum, molybdenum, tantalum, yttrium, nickel, gold, silver and platinum, and in the high-power pulsed magnetron sputtering process, the sputtering power of each of the above-mentioned metal targets ranges from 0.5 kW to 5 kW. Based on the above necessary technical means, the following subsidiary technical means can be further derived. Preferably, the insulating substrate is made of glass or ceramic. Based on the above necessary technical means, the following subsidiary technical means can be further derived. Preferably, when fixing the insulating substrate with a rotary fixing jig, the following steps are also included: First, prepare the insulating substrate, and then remove the grease attached to the insulating substrate. Second, clean the insulating substrate with pure water, and then dry the insulating substrate. Finally, place the insulating substrate in an oven for drying, and place the insulating substrate in the sputtering chamber within an effective time limit. Based on the above necessary technical means, the following subsidiary technical means can be further derived. Preferably, when performing a high-power pulsed magnetron sputtering process, the following steps are also included: First, apply an electric field in the sputtering chamber to dissociate argon gas to form an argon ion, and use the argon ion to bombard the insulating substrate. Second, use a metal ion generated by a metal target to perform ion bombardment on the insulating substrate. Finally, perform a high-power pulsed magnetron sputtering process to deposit an adhesion buffer layer on the inner wall of the high aspect ratio through hole for subsequent hole filling process. Based on the above necessary technical means, the following subsidiary technical means can be further derived. Preferably, the high-power pulsed magnetron sputtering system is also provided with a conductive plate adjacent to the rotary fixing jig, and the conductive plate is used to control the ion movement direction of a metal ion by using a bias voltage. Based on the above necessary technical means, the following subsidiary technical means can be further derived. Preferably, when performing a high-power pulsed magnetron sputtering process, deposit an adhesion buffer layer on the inner wall of the high aspect ratio through hole by single-sided coating, double-sided coating or planetary rotation coating. In summary, the method of the present invention for forming an adhesion buffer layer on the wall of a high aspect ratio through hole of an insulating substrate uses a high-power pulsed magnetron sputtering system to perform a high-power pulsed magnetron sputtering process, and deposits an adhesion buffer layer on the inner wall of the high aspect ratio through hole of the insulating substrate for subsequent hole filling process to fill the high aspect ratio through hole with a conductive metal. Compared with the traditional sputtering process, the high-power pulsed magnetron sputtering process has higher ion kinetic energy, can perform deposition processing on high aspect ratio through holes, and has better bonding strength, and the film is not easy to fall off. In addition, compared with the wet process, the high-power pulsed magnetron sputtering process is a dry process, does not require the use of chemical solutions during the process, and does not require the treatment of waste liquid, thus having the advantages of lower cost and no pollution. The specific embodiments adopted in this creation will be further described by the following embodiments and drawings. Please refer to the first figure. The first figure shows a plan schematic diagram of a high-power pulsed magnetron sputtering system applied to the method of the present invention for forming an adhesion buffer layer on the wall of a high aspect ratio through hole of an insulating substrate. As shown in the first figure, the method provided by the first embodiment of the present invention for forming an adhesion buffer layer on the wall of a high aspect ratio through hole of an insulating substrate is applied to a high-power pulsed magnetron sputtering system 100. The high-power pulsed magnetron sputtering system 100 has a sputtering chamber SC, and a revolving platform RT and a plurality of metal targets are arranged in the sputtering chamber SC. The revolving platform RT is provided with a plurality of rotating disks (only one rotating disk RD1 is marked). In this embodiment, a total of six metal targets TG1 to TG6 are included and are arranged in a surrounding manner with the revolving platform RT as the center. In addition, the metal targets described in this embodiment are composed of at least one of copper, titanium, chromium, zirconium, tungsten, aluminum, molybdenum, tantalum, yttrium, nickel, gold, silver, and platinum. As described above, the metal targets TG1 to TG6 are electrically connected to the high-power pulsed magnetron power supplies TGPS1 to TGPS6 respectively, and the models of the high-power pulsed magnetron power supplies can be, for example, Hüttinger 4002 G2 or Melec SPIK 3000A. In addition, the high-power pulsed magnetron sputtering system 100 is further provided with an argon gas supply source GC, a mass flow controller (MFC), a vacuum pump assembly VA, and a bias power supply BPS. The argon gas supply source GC is connected to the sputtering chamber SC through the mass flow controller MFC, and the mass flow controller MFC controls the flow rate of argon gas flowing into the sputtering chamber SC. The model of the bias power supply BPS can be, for example, Hüttinger 4020 G2, which is used to generate a bias voltage. Please refer to the second figure. The second figure shows the flowchart of the steps of the method for forming an adhesion buffer layer on the high aspect ratio through-hole wall of an insulating substrate provided by the first embodiment of the present invention. As shown in the first figure and the second figure, the method for forming an adhesion buffer layer on the high aspect ratio through-hole wall of an insulating substrate includes the following steps S101 to S108. Step S101 is to prepare the high-power pulsed magnetron sputtering system 100 having the sputtering chamber SC. Step S102 is to respectively arrange a plurality of metal targets TG1 to TG6 in the sputtering chamber SC. Step S103 is to fix an insulating substrate 200 having a plurality of high aspect ratio through-holes (only one high aspect ratio through-hole TH is marked) in the sputtering chamber SC with a rotary fixing jig 300 (marked in the fourth figure). Among them, the insulating substrate 200 in this embodiment is composed of glass or ceramic, and the aspect ratio (AR) of one of the high aspect ratio through-holes TH is greater than 4 (in practice, the aspect ratio can reach 10, but it is not limited thereto). As described above, the rotary fixing jig 300 is fixed to the rotating disk RD1 and is used to drive the insulating substrate 200 to rotate when accompanying the rotation of the rotating disk RD1. In practice, the rotary fixing jig 300 can fix the insulating substrate 200 by clamping means, but it is not limited thereto. The structure and working principle of the rotary fixing jig are prior arts and will not be elaborated in this embodiment. Step S104 is to evacuate the sputtering chamber SC to form a quasi-vacuum environment in the sputtering chamber SC. Among them, the quasi-vacuum environment means that the air pressure is extremely low and approaches vacuum. In this embodiment, the vacuum pump assembly VA used in the high-power pulsed magnetron sputtering system 100 includes a mechanical pump, a Roots pump, and a turbomolecular pump. The mechanical pump can reduce the pressure in the sputtering chamber SC to a low vacuum pressure of 5×10 -2 torr, and the Roots pump can further reduce the pressure in the sputtering chamber SC to a medium vacuum pressure of 5×10 -4 torr, and the turbomolecular pump can further reduce the pressure in the sputtering chamber SC to a high vacuum pressure of 5×10 -5 torr (in order to obtain a better vacuum effect, preferably, the turbomolecular pump is used to further reduce the pressure to 1×10 -6 torr). Step S105 is to introduce an argon gas into the sputtering chamber SC. Step S106 is to apply an electric field in the sputtering chamber SC to dissociate the argon gas to form argon ions and use the argon ions to bombard the insulating substrate 200. Among them, the purpose of using the argon ions to bombard the insulating substrate 200 is to remove the fine dust attached to the insulating substrate 200. Step S107 is to use the metal targets TG1 to TG6 to perform ion bombardment on the insulating substrate 200. Among them, the purpose of using the metal targets TG1 to TG6 to perform ion bombardment on the insulating substrate 200 is to clean the surface of the insulating substrate 200 to increase the adhesion of the insulating substrate 200. Step S108 is to deposit and form an adhesion buffer layer ABL (shown in the fifth figure, commonly referred to as the seed layer) on the inner wall of the high aspect ratio through-hole TH of the insulating substrate 200 by using a high power pulsed magnetron sputtering process, for a subsequent hole filling process to fill the high aspect ratio through-hole TH with a conductive metal CM (such as copper, shown in the sixth figure). Among them, in the high power pulsed magnetron sputtering process, the power of the metal targets TG1 to TG6 ranges between 0.5 kW and 5 kW. As described above, in this embodiment, the detailed process parameters of the high power pulsed magnetron sputtering process are shown in Table 1 below. Table 1: High power pulsed magnetron sputtering process parameters of the first embodiment. Please refer to the third figure. The third figure shows the method provided by the first embodiment of the present invention for forming an adhesion buffer layer on the wall of the high aspect ratio through-hole of the insulating substrate, where the flowchart of the detailed preparation steps of the insulating substrate. As shown in the second and third figures, step S103 may further include the following steps S1031 to S1036. Step S1031 is to prepare the insulating substrate 200. Step S1032 is to remove the grease attached to the insulating substrate 200. Step S1033 is to clean the insulating substrate 200 with pure water. Step S1034 is to dry the insulating substrate 200. Step S1035 is to place the insulating substrate 200 in an oven for drying. Step S1036 is to place the insulating substrate 200 in the sputtering chamber SC within a valid time limit. As described above, step 1034 is, for example, to dry the insulating substrate 200 by blowing air with an air gun. Step 1035 is, for example, to put the dried insulating substrate 200 into an oven preheated to 70 °C and dry it in the oven for 10 minutes to ensure that no moisture remains. The valid time limit of step 1036 is, for example, one hour, mainly to prevent the dried insulating substrate 200 from being contaminated due to being placed in the open environment for too long. Please refer to the fourth figure. The fourth figure shows the three-dimensional schematic diagram of the high power pulsed magnetron sputtering process in the form of single-sided coating provided by the first embodiment of the present invention for forming an adhesion buffer layer on the wall of the high aspect ratio through-hole of the insulating substrate. As shown in the fourth figure, the high power pulsed magnetron sputtering system 100 is also provided with a conductive plate CP adjacent to the rotary fixture 300 (in practice, the conductive plate CP is fixed to the rotary platform RT and rotates with the rotary platform RT, but not limited thereto), and both the conductive plate CP and the rotary fixture 300 are electrically connected to the bias power supply BPS. When performing the high-power pulsed magnetron sputtering process, it can be divided into single-sided coating, double-sided coating, and public self-rotation coating according to different coating forms. In this embodiment, single-sided coating will be described, and double-sided coating and public self-rotation coating will be described in subsequent embodiments. When performing single-sided coating, the revolving platform RT continuously rotates along a revolving direction D1, and the self-rotating disk RD1 remains stationary. In other words, the insulating substrate 200 will rotate along with the revolving platform RT and always maintain a single side (the same side) facing the metal targets TG1 to TG6. As mentioned above, during the process, the metal target (taking the metal target TG1 as an example) will periodically sputter out a plurality of metal ions (only one metal ion MI is marked), and under the action of the electric field, it will accelerate and fly towards the insulating substrate 200 (compared with the wet process, when performing the high-power pulsed magnetron sputtering process, the metal ion MI has higher energy and can be embedded in the inner wall with better bonding force). In order to make the metal ion MI fly towards the high aspect ratio through hole TH of the insulating substrate as much as possible, a bias voltage is generated at the conductive plate CP by the bias power supply BPS to control the ion movement direction IMD of the metal ion MI. In addition, when the metal ion MI starts to deposit on the high aspect ratio through hole TH, the electricity generated by the bias power supply BPS can be transmitted to the adhesion buffer layer ABL through the rotary fixture 300, and then a bias voltage is generated at the insulating substrate 200 to control the ion movement direction IMD of the metal ion MI. Please refer to the fifth figure. The fifth figure shows the method provided by the first embodiment of the present invention for forming an adhesion buffer layer on the wall of the high aspect ratio through hole of the insulating substrate, where a cross-sectional schematic diagram of the adhesion buffer layer deposited on the inner wall of the high aspect ratio through hole is shown. As shown in the fifth figure, after the high-power pulsed magnetron sputtering process is performed in the form of single-sided coating, the adhesion buffer layer ABL is deposited on the inner wall of the high aspect ratio through hole TH (the contour of the through hole TH is represented by a dotted line). The high aspect ratio through hole TH has a through hole depth HD and a through hole width HW. In this embodiment, the through hole depth HD and the through hole width HW are 450 μm and 100 μm respectively, that is, the aspect ratio is 4.5. As mentioned above, the adhesion buffer layer ABL has a surface layer thickness ST, a first inner wall thickness IT1, a second inner wall thickness IT2, and a third inner wall thickness IT3 respectively. In this embodiment, the surface layer thickness STa, the first inner wall thickness IT1a, the second inner wall thickness IT2a, and the third inner wall thickness IT3a are 590 nm, 275 nm, 45 nm, and 25 nm respectively. Please refer to FIG. 6. FIG. 6 shows a cross-sectional schematic view of a method for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate according to the first embodiment of the present invention, in which a subsequent via filling process is performed to fill the high aspect ratio via with conductive metal. As shown in FIG. 6, after the adhesion buffer layer ABL is deposited on the inner wall of the high aspect ratio via TH, the subsequent via filling process can be continued to fill the high aspect ratio via with conductive metal CM to complete the preparation of the interposer. Compared with directly adhering to the insulating material 200, the bonding force between the conductive metal CM and the adhesion buffer layer ABL is better. Therefore, by first depositing the adhesion buffer layer ABL on the inner wall of the high aspect ratio via HL, it is more beneficial to perform the subsequent via filling process (such as wet or dry process). Please refer to FIGS. 7 and 8. FIG. 7 shows a three-dimensional schematic view of a high-power pulsed magnetron sputtering process performed in a bilateral coating form for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate according to the second embodiment of the present invention; and FIG. 8 shows a cross-sectional schematic view of a method for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate according to the second embodiment of the present invention, in which an adhesion buffer layer is deposited on the inner wall of the high aspect ratio via. Please refer to FIGS. 1 to 6 together. The high-power pulsed magnetron sputtering system 100, steps S101 to S108, and steps S1031 to S1036 of the second embodiment are the same as or similar to those of the first embodiment. Please refer to the descriptions in the corresponding paragraphs and will not be repeated in this embodiment. The difference between the second embodiment and the first embodiment is that the second embodiment performs the high-power pulsed magnetron sputtering process in a bilateral coating form. The first half of the bilateral coating process is the same as that of the unilateral coating. The revolution platform RT continuously rotates along the revolution direction D1, and the turntable RD1 remains stationary. After the first half of the process ends (for example, when it reaches half of the deposition time), the revolution platform RT stops rotating. At the beginning of the second half of the bilateral coating process, the turntable RD1 will first rotate 180 degrees along a rotation direction D2, that is, turn the other side of the insulating substrate 200 towards the metal targets TG1 to TG6, and then make the revolution platform RT continue to rotate along the revolution direction D1 to complete the second half of the process. In other words, the bilateral coating consists of two unilateral coatings and the surface is changed during the process to uniformly coat both sides of the insulating substrate 200. After the high-power pulsed magnetron sputtering process is carried out in a bilateral coating form, an adhesion buffer layer ABL is deposited and formed on the inner wall of the high aspect ratio through hole TH, and has a surface layer thickness STb, a first inner wall thickness IT1b, a second inner wall thickness IT2b and a third inner wall thickness IT3b respectively. In this embodiment, the surface layer thickness STb, the first inner wall thickness IT1b, the second inner wall thickness IT2b and the third inner wall thickness IT3b are 715 nm, 250 nm, 85 nm and 210 nm respectively. It can be clearly seen that the adhesion buffer layer ABL is deposited on both sides of the bilateral coating, while for the unilateral coating, the adhesion buffer layer ABL is only deposited on the surface adjacent to the metal targets TG1 to TG6. In addition, after the bilateral coating, the adhesion buffer layer ABL not only has a larger average inner wall thickness, but is also more uniform, which is more beneficial for the subsequent hole filling process. As shown in the ninth and tenth figures, the ninth figure shows a three-dimensional schematic diagram of the method for forming an adhesion buffer layer on the inner wall of a high aspect ratio through hole of an insulating substrate provided by the third embodiment of the present invention, in which the high-power pulsed magnetron sputtering process is carried out in a planetary rotation coating form; and the tenth figure shows a cross-sectional schematic diagram of the method for forming an adhesion buffer layer on the inner wall of a high aspect ratio through hole of an insulating substrate provided by the third embodiment of the present invention, in which the adhesion buffer layer is deposited and formed on the inner wall of the high aspect ratio through hole. Please refer to the first to sixth figures together. Steps S101 to S108 and steps S1031 to S1036 of the third embodiment are the same as or similar to those of the first embodiment. Please refer to the descriptions in the corresponding paragraphs and will not be repeated in this embodiment. The difference between the third embodiment and the first embodiment is that the third embodiment carries out the high-power pulsed magnetron sputtering process in a planetary rotation coating form. The rotary fixture 300 is provided with at least one rotating disk (only one rotating disk RD2 is marked), and the rotating disk RD2 is provided with a structure capable of fixing the insulating substrate 200. When carrying out the planetary rotation coating, the rotary platform RT continuously rotates along a rotation direction D1, and the rotating disks RD1 and RD2 continuously rotate along a rotation direction D2 and a rotation direction D3 respectively. In other words, during the process, the insulating substrate 200 will continuously rotate to increase its throwing power. After the high-power pulsed magnetron sputtering process is carried out in a planetary rotation coating form, an adhesion buffer layer ABL is deposited and formed on the inner wall of the high aspect ratio through hole TH, and has a surface layer thickness STc, a first inner wall thickness IT1c, a second inner wall thickness IT2c and a third inner wall thickness IT3c respectively. In this embodiment, the surface layer thickness STc, the first inner wall thickness IT1c, the second inner wall thickness IT2c and the third inner wall thickness IT3c are 450 nm, 210 nm, 45 nm and 180 nm respectively. It can be clearly seen that the adhesion buffer layer ABL is deposited on both sides of the planetary-rotary plating film, while for the single-sided plating film, the adhesion buffer layer ABL is only deposited on the surface adjacent to the metal targets TG1 to TG6. After the planetary-rotary plating, the average inner wall thickness of the adhesion buffer layer ABL is slightly smaller than that of the double-sided plating film, but its uniformity is still better than that of the single-sided plating film, which is also beneficial to the subsequent via filling process. In practice, all three plating methods (single-sided plating, double-sided plating, and planetary-rotary plating) can complete the deposition of the adhesion buffer layer ABL. In other words, the current can be vertically conducted from one surface of the insulating substrate 200 to the other surface through the adhesion buffer layer ABL. In summary, the method for forming an adhesion buffer layer on the high aspect ratio via wall of an insulating substrate according to the present invention utilizes the high power pulsed magnetron sputtering system 100 to perform a high power pulsed magnetron sputtering process, and deposits and forms the adhesion buffer layer ABL on the inner wall of the high aspect ratio via TH of the insulating substrate 200 for subsequent via filling process to fill the high aspect ratio via TH with the conductive metal CM. Compared with the traditional sputtering process, the high power pulsed magnetron sputtering process has higher ion kinetic energy, can perform deposition processing on high aspect ratio vias, and has better adhesion, and the thin film is not easily peeled off. In addition, compared with the wet process, the high power pulsed magnetron sputtering process is a dry process, which does not require the use of chemical solutions during the process and does not require additional treatment of waste liquid, thus having the advantages of lower cost and no pollution. Through the detailed description of the above preferred specific embodiments, it is hoped to more clearly describe the features and spirit of the present invention, rather than limiting the scope of the present invention by the above-disclosed preferred specific embodiments. On the contrary, the purpose is to cover various changes and equivalent arrangements within the scope of the patent application of the present invention. 100: High-power pulsed magnetron sputtering system 200: Insulating substrate 300: Rotary fixing jig TH: High aspect ratio through hole SC: Sputtering chamber RT: Revolving platform RD1, RD2: Rotating disks CP: Conductive plate TG1~TG6: Metal targets TGPS1~TGPS6: High-power pulsed magnetron power supply BPS: Bias power supply GC: Argon gas supply source MFC: Mass flow controller VA: Vacuum pump assembly MI: Metal ions IMD: Ion movement direction ABL: Adhesion buffer layer CM: Conductive metal HD: Through hole depth HW: Through hole width STa, STb, STc: Surface thickness IT1a, IT1b, IT1c: First inner wall thickness IT2a, IT2b, IT2c: Second inner wall thickness IT3a, IT3b, IT3c: Third inner wall thickness D1: Revolving direction D2, D3: Rotating directions S101~S108: Steps S1031~S1036: Steps The first figure shows a schematic plan view of a high-power pulsed magnetron sputtering system applied to the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate according to the present invention; the second figure shows a flowchart of the steps of the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the first embodiment of the present invention; the third figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the first embodiment of the present invention, wherein the flowchart of the detailed preparation steps of the insulating substrate; the fourth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the first embodiment of the present invention, wherein the three-dimensional schematic diagram of the high-power pulsed magnetron sputtering process carried out in the form of single-sided coating; the fifth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the first embodiment of the present invention, wherein the cross-sectional schematic diagram of the adhesion buffer layer formed on the inner wall of the high aspect ratio through-hole; the sixth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the first embodiment of the present invention, wherein the cross-sectional schematic diagram of the subsequent hole filling process to fill the high aspect ratio through-hole with conductive metal; the seventh figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the second embodiment of the present invention, wherein the three-dimensional schematic diagram of the high-power pulsed magnetron sputtering process carried out in the form of double-sided coating; the eighth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the second embodiment of the present invention, wherein the cross-sectional schematic diagram of the adhesion buffer layer formed on the inner wall of the high aspect ratio through-hole; the ninth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the third embodiment of the present invention, wherein the three-dimensional schematic diagram of the high-power pulsed magnetron sputtering process carried out in the form of planetary rotation coating; and the tenth figure shows the method for forming an adhesion buffer layer on the high aspect ratio through-hole walls of an insulating substrate provided by the third embodiment of the present invention, wherein the cross-sectional schematic diagram of the adhesion buffer layer formed on the inner wall of the high aspect ratio through-hole. S101~S108: Steps

Claims

1. A method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate, comprising the following steps: (a) preparing a high power pulsed magnetron sputtering system, and the high power pulsed magnetron sputtering system has a sputtering chamber; (b) disposing a plurality of metal targets in the sputtering chamber; (c) fixing an insulating substrate having a plurality of high aspect ratio vias in the sputtering chamber with a rotary fixture, wherein, The aspect ratio of each high aspect ratio through hole is greater than 4; (d) evacuate the sputtering chamber to make the pressure in the sputtering chamber lower than 5×10 -5 torr; (e) introduce argon gas into the sputtering chamber; and (f) perform a high power pulsed magnetron sputtering process to deposit an adhesion buffer layer on the inner walls of the high aspect ratio through holes for a subsequent hole filling process to fill the high aspect ratio through holes with a conductive metal; wherein each of the above metal targets is composed of at least one of copper, titanium, chromium, zirconium, tungsten, aluminum, molybdenum, tantalum, yttrium, nickel, gold, silver and platinum, and in the high power pulsed magnetron sputtering process, the sputtering power of each of the above metal targets ranges from 0.5 kW to 5 kW.

2. The method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate as described in claim 1, wherein, the insulating substrate is made of glass or ceramic.

3. The method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate as described in claim 1, wherein, step (c) further comprises the following steps: (c1) preparing the insulating substrate; (c2) removing the grease attached to the insulating substrate; (c3) cleaning the insulating substrate with pure water; (c4) drying the insulating substrate; (c5) placing the insulating substrate in an oven for drying; and (c6) placing the insulating substrate in the sputtering chamber within a valid time limit.

4. The method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate as described in claim 1, wherein, step (f) further comprises the following steps: (f1) applying an electric field in the sputtering chamber to dissociate the argon gas to form an argon ion, and bombarding the insulating substrate with the argon ion; (f2) ion-bombarding the insulating substrate with a metal ion generated by the metal targets; and (f3) performing the high power pulsed magnetron sputtering process to deposit and form the adhesion buffer layer on the inner wall of the high aspect ratio via for performing the subsequent hole filling process.

5. The method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate as described in claim 4, wherein, the high power pulsed magnetron sputtering system is further provided with a conductive plate adjacent to the rotary fixture, and the conductive plate is used to control the ion movement direction of the metal ion by means of a bias voltage.

6. The method for forming an adhesion buffer layer on the walls of high aspect ratio vias of an insulating substrate as described in claim 1, wherein, when performing the high power pulsed magnetron sputtering process, the adhesion buffer layer is deposited and formed on the inner wall of the high aspect ratio vias by single-sided coating, double-sided coating or planetary rotation coating.

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