Coating process of glass packaging substrate and glass packaging substrate

Abstract

The invention discloses a coating process of a glass packaging substrate and the glass packaging substrate, and the coating process comprises the following steps: selecting a magnetron sputtering instrument, installing a nickel chromium target material and a copper target material, and placing the glass substrate on a plating rack of the magnetron sputtering instrument; sequentially starting a mechanical pump and a molecular pump to vacuumize the vacuum cavity; sequentially carrying out direct-current magnetron sputtering on a nickel chromium bonding layer and a copper film layer on the surface of the glass substrate; and after the processed product is taken out, the vacuum cavity is kept in a vacuum state and is shut down. A direct-current sputtering metallization method is adopted, the nickel chromium bonding layer is sputtered on the glass substrate, then the copper film layer is sputtered on the nickel chromium bonding layer, the bonding strength of the copper film metal layer and the glass substrate can be improved, the surface of the metal layer is smooth, the organization structure is meticulous, and the conductivity is good; and the product quality and reliability of the semiconductor and microelectronic packaging glass substrate are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of glass packaging substrates, and particularly relates to a coating process for glass packaging substrates and a glass packaging substrate. Background Art

[0002] As Moore's Law gradually approaches its physical limit, traditional semiconductor and microelectronics packaging technologies can no longer meet the requirements of high integration, high performance, high lightweight, low cost, and low energy consumption of AI and chips. The semiconductor and microelectronics packaging technologies are developing towards the three-dimensional stacking direction of chips, and the through-hole structure plays a key role in connecting the upper and lower chips in 3D integrated packaging. The three commonly used interposers in three-dimensional integrated packaging are: organic through-hole interposer, through-silicon via interposer, and glass through-hole interposer. Among them, the glass substrate has excellent high-frequency electrical properties, easy processing, low cost, low thermal expansion coefficient, strong mechanical stability, good chemical stability, etc. compared with the other two substrates, and is recognized as the next-generation semiconductor and microelectronics packaging substrate to promote the continued development of Moore's Law.

[0003] When using glass materials as packaging substrates, it is generally necessary to prepare a copper thin film seed layer with a certain bonding strength on its surface for subsequent electroplating filling of holes, connecting the upper and lower chips and the RDL re-wiring on the glass surface. The methods for preparing copper thin films on glass substrates mainly include chemical vapor deposition method, electroplating method, and sputtering method, etc. At present, the magnetron sputtering technology is a commonly used method for preparing copper thin films on glass packaging substrates. The advantages of magnetron sputtering are high sputtering rate of the thin film, good film-substrate adhesion, and low substrate temperature, etc.

[0004] In the prior art, copper films are usually directly sputtered on the surface of glass substrates; however, due to the certain chemical inertness, high smoothness, and difference in thermal expansion coefficient of the glass material surface, the bonding strength between the copper thin film metal layer and the glass substrate is not high, usually only 20 - 30N, and the film-forming performance is poor, which greatly affects the product quality and reliability. Summary of the Invention

[0005] In order to solve some or all of the problems existing in the above prior art, on the one hand, the present invention provides a coating process for a glass packaging substrate, including the following steps: S100: Preparation before starting up, select a magnetron sputtering instrument, install a nickel chromium target and a copper target, and place the glass substrate on the plating rack of the magnetron sputtering instrument; S200: Evacuate the vacuum chamber, start the mechanical pump and the molecular pump in sequence to evacuate the vacuum chamber, so that the background vacuum degree of the vacuum chamber is pumped to ≤6×10 -3 Pa; S300: Coating. A nickel chromium bonding layer and a copper film layer are sequentially deposited on the surface of the glass substrate by DC magnetron sputtering. Among them, the thickness of the nickel chromium bonding layer is 30 ± 5 nm, and the thickness of the copper film layer is 350 ± 20 nm; S400: Shut down. After taking out the processed product, keep the vacuum chamber in a vacuum state and then shut down.

[0006] As a further improvement of the present invention, in step S100, before placing the glass substrate on the plating rack of the magnetron sputtering instrument, the glass substrate is ultrasonically cleaned for at least 30 minutes, and then the glass substrate is fixed on the steel disc with double-sided tape, and then the steel disc is placed on the plating rack in the vacuum chamber.

[0007] As a further improvement of the present invention, step S200, evacuating the vacuum specifically includes the following steps: First start the mechanical pump, extract the vacuum degree of the vacuum chamber to <10 Pa, then start the molecular pump. After the molecular pump continuously works for 30 - 50 minutes, make the vacuum degree of the vacuum chamber reach ≤ 6×10 -3 Pa.

[0008] As a further improvement of the present invention, the initial rotation speed of the molecular pump is 450 r / min, and the rotation speed can rise to 27000 r / min after working for 8 - 10 minutes. The working frequency is 450 Hz, the voltage is 5 ± 0.2 V, and the current is 2.7 ± 0.3 A.

[0009] As a further improvement of the present invention, step S300, coating specifically includes the following steps: S301: Introduce argon and oxygen into the vacuum chamber, and clean the surface of the glass substrate with an ion source; S302: When the air pressure in the vacuum chamber reaches the preset air pressure, turn on the DC power supply, and deposit the nickel chromium bonding layer on the surface of the glass substrate by DC magnetron sputtering. The parameters are: the argon flow rate is 60 sccm, and the sputtering power is 3 KW; S303: Deposit the copper film layer on the surface of the nickel chromium bonding layer by DC magnetron sputtering. The sputtering parameters are: the argon flow rate is 60 sccm, and the sputtering power is 4 KW.

[0010] As a further improvement of the present invention, in step S301, the argon flow rate and the oxygen flow rate introduced into the vacuum chamber are each 100 sccm, and the duration of cleaning the surface of the glass substrate with an ion source is 90 S.

[0011] As a further improvement of the present invention, the traveling speed of sputtering the nickel chromium bonding layer in step S302 and sputtering the copper film layer in step S303 is both 50 mm / s.

[0012] As a further improvement of the present invention, step S400, shutting down includes the following steps: Turn off the molecular pump and mechanical pump in sequence, and open the bleed valve. After the air pressure in the vacuum chamber reaches atmospheric pressure, take out the processed product. After taking out the processed product, start the molecular pump to evacuate the vacuum chamber again. When the air pressure in the vacuum chamber ≤ 1×10 -2 Pa, turn off the molecular pump, and then turn off the power supply of the magnetron sputtering instrument.

[0013] As a further improvement of the present invention, the resistivity of the copper film layer ≤ 2.3×10 -8 Ω·m.

[0014] On the other hand, the present invention also provides a glass encapsulated substrate prepared by the above process, including a glass substrate body. A nickel chromium bonding layer is provided on the outer surface of the glass substrate body, and a copper film layer is provided on one surface of the nickel chromium bonding layer away from the glass substrate body.

[0015] Compared with the prior art, the beneficial effects of the present invention are: The present invention adopts the DC sputtering metallization method. First, a nickel chromium bonding layer is sputtered on the glass substrate, and then a copper film layer is sputtered on the nickel chromium bonding layer, which can improve the bonding strength between the copper thin film metal layer and the glass substrate. The actual measurement by a scratch tester shows that the average critical bonding force of the copper thin film in the present invention reaches nearly 80N, far greater than the bonding strength of 20 - 30N of the copper thin film in the prior art. The metal layer prepared by the DC magnetron sputtering technology has a smooth surface, a dense organizational structure, and good electrical conductivity, greatly improving the product quality and reliability of the semiconductor and microelectronic packaging glass substrate. Description of the Drawings

[0016] In order to more clearly illustrate the solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is the process flow chart of the embodiment of the present invention; Figure 2 is the structural schematic diagram of the glass encapsulated substrate prepared by the embodiment of the present invention. Detailed Embodiments

[0018] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the technical field to which the present invention pertains; the terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present invention or the above drawings are used to distinguish different objects and not to describe a specific order.

[0019] Reference to "embodiments" in the present invention means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an exclusive, independent, or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present invention can be combined with other embodiments.

[0020] To enable those skilled in the technical field to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings.

[0021] As Figure 1 、 Figure 2 shown, a coating process for a glass encapsulated substrate includes the following steps: S100: Startup preparation, select a magnetron sputtering instrument, install a nickel chromium target and a copper target, and place the glass substrate on the coating rack of the magnetron sputtering instrument; S200: Evacuate the vacuum chamber. Start the mechanical pump and the molecular pump in sequence to evacuate the vacuum chamber, so that the background vacuum degree of the vacuum chamber is pumped to ≤6×10 -3 Pa; S300: Coating. Direct current magnetron sputter a nickel chromium adhesive layer and a copper film layer on the surface of the glass substrate in sequence. Among them, the thickness of the nickel chromium adhesive layer is 30±5 nm, and the thickness of the copper film layer is 350±20 nm; S400: Shutdown. After taking out the processed product, keep the vacuum state of the vacuum chamber and then shut down.

[0022] The coating process of the glass encapsulated substrate adopts the DC sputtering metallization method. First, a nickel chromium bonding layer is sputtered on the glass substrate, and then a copper film layer is sputtered on the nickel chromium bonding layer, which can improve the bonding strength between the copper thin film metal layer and the glass substrate. After actual measurement by a scratch tester, the average critical bonding force of the copper thin film in the present invention reaches nearly 80 N, which is far greater than the bonding strength of 20 - 30 N of the copper thin film in the prior art. On the other hand, the encapsulated glass substrate is prepared by DC magnetron sputtering technology. The surface of the copper film layer is smooth, the tissue structure is dense, and it has good electrical conductivity. The measured resistivity of the copper film layer does not exceed 2.3×10 -8 (Ω·m), which is very close to the intrinsic resistivity of copper, 1.7x10 -8 (Ω·m); It greatly improves the product quality and reliability of semiconductor and microelectronic packaging glass substrates.

[0023] It should be noted that in step S100, before placing the glass substrate on the plating rack of the magnetron sputtering instrument, the glass substrate needs to be ultrasonically cleaned for at least 30 minutes, and then the glass substrate is bonded to the steel plate with double-sided tape, and then the steel plate is placed on the plating rack in the vacuum chamber. Among them, the double-sided tape used here is a special double-sided tape, which is made of a vacuum-compatible material with high temperature resistance and low outgassing rate.

[0024] The above step S100, the startup preparation specifically includes the following steps: S101: Turn on the water chiller and the cooling water pump, detect that the water flow velocity of the cooling water path is normal, and confirm that the water cooling system is working properly; S102: Detect the electrical system to ensure that the power distribution wires in the power supply box are intact, the power supply wires are correctly connected to the target position, and the instrument ground wire is correctly grounded and intact; S103: Detect the vacuum system, check whether the vacuum pump oil reaches the marked line, detect whether all electromagnetic valves are in the closed state and intact and correctly connected to the computer control system; S104: Install the nickel chromium target and the copper target in sequence, and install the glass substrate on the plating rack of the magnetron sputtering instrument.

[0025] The above step S200, the vacuum pumping specifically includes the following steps: Start the vacuum system. Press the automatic vacuum acquisition button on the control software interface. The indicator light will turn on. First, start the mechanical pump, which pumps air out of the vacuum chamber. When the vacuum degree of the vacuum chamber is pumped down to less than 10 Pa, start the molecular pump. When the molecular pump starts, its rotational speed is 450 r / min. As time goes by, the rotational speed of the molecular pump will increase. After the molecular pump runs for 8 to 10 minutes, the rotational speed can reach the maximum value of 27,000 r / min, the working frequency is 450 Hz, the working voltage is maintained at 5 ± 0.2 V, and the working current is maintained at 2.7 ± 0.3 A. If the opening time of the vacuum chamber door is short, the chamber pressure should reach below 8x10 - 3 Pa after the molecular pump works for 8 - 10 minutes; if the opening time of the vacuum chamber door to the atmospheric pressure is long, it takes about 30 minutes of continuous pumping by the molecular pump for the chamber pressure to reach below 8x10 -3 Pa. And due to the excessive water vapor in the air entering, the working current of the molecular pump slightly increases and is maintained at about 3 A. As the subsequent water vapor is pumped out, it will drop back to about 2.7 A. Continuously pump for 30 - 50 minutes until the pressure of the vacuum chamber reaches 6x10 -3 Pa and then start the next step of work.

[0026] In the above step S300, the coating includes the following steps: S301: Introduce argon and oxygen into the vacuum chamber and clean the surface of the glass substrate using an ion source. Specifically, introduce argon and oxygen with a flow rate of 100 sccm each into the vacuum chamber; set the ion source power to 0.8 KW and use the ion source to clean the surface of the glass substrate for 90 S. After introducing the gas into the vacuum chamber, the vacuum degree of the vacuum chamber will decrease and the pressure will increase. When the pressure increases to 0.5 Pa, the next step can be started.

[0027] S302: When the pressure in the vacuum chamber reaches the preset pressure, turn on the DC power supply and deposit a nickel chromium bonding layer on the surface of the glass substrate by DC magnetron sputtering. The sputtering parameters are: argon flow rate is 60 sccm, and the sputtering power is 3 KW.

[0028] S303: Deposit a copper film layer on the surface of the nickel chromium bonding layer by DC magnetron sputtering. The sputtering parameters are: argon flow rate is 60 sccm, and the sputtering power is 4 KW.

[0029] Among them, when sputtering the nickel chromium bonding layer and the copper film layer, it is necessary to control the traveling speed of the magnetron sputtering instrument to be 50 mm / s.

[0030] S400, shutting down includes the following steps: After the coating process is completed, close the target baffle and the substrate baffle, then turn off the DC power supply, and then close the main gas valve, the argon gas valve and the argon gas flow meter. Then press the automatic vacuum-breaking button, and the rotation speed of the molecular pump starts to decrease. After 8 minutes, the molecular pump enters the fully standby state, and then turn off the mechanical pump; after confirming that the molecular pump and the mechanical pump are completely turned off, open the bleed valve. After the air pressure in the vacuum chamber reaches atmospheric pressure, open the chamber and take out the processed product; after taking out the processed product, start the molecular pump again to evacuate the vacuum chamber. When the air pressure in the vacuum chamber ≤ 1×10 -2 Pa, turn off the molecular pump, and then turn off the power supply of the magnetron sputtering instrument. After taking out the product, evacuate the vacuum chamber again to keep the vacuum chamber of the magnetron sputtering instrument in a vacuum state when shutting down, so as to facilitate the next processing and improve the efficiency.

[0031] As Figure 2 shown, the glass encapsulation substrate fabricated by the above process is a layered structure, including a glass substrate body 1. A nickel-chromium bonding layer 2 is deposited on the outer surface of the glass substrate body 1 by DC magnetron sputtering technology. A copper film layer 3 is deposited on the surface of the nickel-chromium bonding layer 2 away from the glass substrate body 1 by DC magnetron sputtering technology. Among them, the thickness of the nickel-chromium bonding layer 2 is 30±5nm, and the thickness of the copper film layer 3 is 350±20nm.

[0032] The above specific embodiments are the preferred embodiments of the present invention, and do not limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to this specific embodiment. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims

1. A coating process for a glass encapsulated substrate, characterized in that: It includes the following steps: S100: Preparation before starting up, select a magnetron sputtering instrument, install a nickel chromium target and a copper target, and place the glass substrate on the plating rack of the magnetron sputtering instrument; S200: Evacuate the air. Start the mechanical pump and the molecular pump in sequence to evacuate the vacuum chamber so that the background vacuum degree of the vacuum chamber is pumped down to ≤ 6×10 -3 Pa; S300: Coating, sequentially direct current magnetron sputter a nickel chromium bonding layer and a copper film layer on the surface of the glass substrate. Among them, the thickness of the nickel chromium bonding layer is 30±5 nm, and the thickness of the copper film layer is 350±20 nm; S400: Shut down, keep the vacuum chamber in a vacuum state after taking out the processed product and then shut down.

2. The coating process of the glass encapsulated substrate according to claim 1, characterized in that: In step S100, before placing the glass substrate on the plating rack of the magnetron sputtering instrument, first ultrasonically clean the glass substrate for no less than 30 minutes, then fix the glass substrate on the steel plate with double-sided tape, and then place the steel plate on the plating rack in the vacuum chamber.

3. The coating process of the glass encapsulated substrate according to claim 1, characterized in that: Step S200, the specific steps of vacuum pumping include the following: First, start the mechanical pump and pump down the vacuum chamber to a vacuum level of < 10 Pa, then start the molecular pump. After the molecular pump has been operating continuously for 30 - 50 minutes, the vacuum level in the vacuum chamber reaches ≤ 6×10 -3 Pa.

4. The coating process of the glass encapsulated substrate according to claim 3, wherein: The initial speed of the molecular pump is 450 r / min, and the speed can rise to 27000 r / min after working for 8 - 10 minutes. The working frequency is 450 Hz, the voltage is 5±0.2 V, and the current is 2.7±0.3 A.

5. The coating process of the glass encapsulated substrate according to claim 1, characterized in that: Step S300, the specific steps of coating include the following: S301: Introduce argon and oxygen into the vacuum chamber, and use an ion source to clean the surface of the glass substrate; S302: When the air pressure in the vacuum chamber reaches the preset air pressure, turn on the direct current power supply, and directly current magnetron sputter deposit a nickel chromium bonding layer on the surface of the glass substrate. The parameters are: the argon flow rate is 60 sccm, and the sputtering power is 3 KW; S303: Direct current magnetron sputter deposit a copper film layer on the surface of the nickel chromium bonding layer. The sputtering parameters are: the argon flow rate is 60 sccm, and the sputtering power is 4 KW.

6. The coating process of the glass encapsulated substrate according to claim 5, characterized in that: In step S301, the argon flow rate and the oxygen flow rate introduced into the vacuum chamber are each 100 sccm, and the duration of using the ion source to clean the surface of the glass substrate is 90 S.

7. The coating process of the glass encapsulation substrate according to claim 5, characterized in that: The traveling speed of sputtering the nickel chromium bonding layer in step S302 and sputtering the copper film layer in step S303 is both 50 mm / s.

8. The coating process of the glass encapsulated substrate according to claim 1, characterized in that: Step S400, shutting down includes the following steps: Turn off the molecular pump and mechanical pump in sequence, and open the bleed valve. After the air pressure in the vacuum chamber reaches atmospheric pressure, take out the processed product; after taking out the processed product, start the molecular pump again to evacuate the vacuum chamber. When the air pressure in the vacuum chamber ≤ 1×10 -2 Pa, turn off the molecular pump, and then turn off the power supply of the magnetron sputtering instrument.

9. The coating process of the glass encapsulated substrate according to claim 1, characterized in that: The resistivity of the copper film layer ≤ 2.3×10 -8 Ω·m.

10. A glass encapsulation substrate prepared by a coating process using the glass encapsulation substrate according to any one of claims 1-9, characterized in that: It includes a glass substrate body, and a nickel chromium bonding layer is provided on the outer surface of the glass substrate body. A copper film layer is provided on one side surface of the nickel chromium bonding layer away from the glass substrate body.

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