CN115831740A

CN115831740A - Board-level packaged metal etching device and method

Info

Publication number: CN115831740A
Application number: CN202211601893.6A
Authority: CN
Inventors: 上官昌平; 杜玲玲; 颜国秋; 查晓刚; 王建彬; 黄剑
Original assignee: Shanghai Meadville Science and Technology Co Ltd
Current assignee: Shanghai Meadville Science and Technology Co Ltd
Priority date: 2022-12-13
Filing date: 2022-12-13
Publication date: 2023-03-21

Abstract

The invention provides a board level packaging metal etching device and a method, wherein the method comprises the following steps: fixing a packaging carrier plate in the reaction cavity, wherein the packaging carrier plate comprises a titanium layer, a copper layer and a first connecting metal layer; and (4) wet etching the copper layer, and allowing the first reaction gas after plasma treatment to enter a reaction cavity for plasma etching the titanium layer. According to the invention, the titanium layer in the board level package is etched by using dry etching, so that the accuracy of processing control is improved, the etching process is shortened, the cost is reduced, the production efficiency is improved, and the environment-friendly concept is met; meanwhile, the processing efficiency of the first reaction gas is improved by separating the plasma generating cavity from the reaction cavity; in addition, a fixed area is arranged at the edge of the packaging carrier plate, so that enough fault-tolerant space is provided, and the processing area is vertically aligned with the plasma channel, so that the etching uniformity of the packaging carrier plate is realized; and finally, setting the pressure intensity in the reaction chamber, and realizing the ion collision maximization while ensuring the etching rate.

Description

Board-level packaged metal etching device and method

Technical Field

The invention belongs to the technical field of semiconductor integrated circuit manufacturing, and particularly relates to a board-level packaged metal etching device and method.

Background

In the conventional wafer level package, the RDL (redistribution layer) is generally fabricated by electroplating, wherein titanium/copper metal is sputtered on a resist layer as a seed layer, and after the electroplating is completed, the residual resist layer is removed, and then the seed layer is removed by a wet method or a dry method. During wet etching, the copper seed layer can be removed by using an ammonium persulfate or acidic hydrogen peroxide system, the titanium seed layer can also be removed by using liquid medicines such as hydrofluoric acid and the like, but the wet etching generally has the characteristic of isotropy, lateral corrosion is easily caused in the wet etching process, so that the verticality of the side wall of the RDL line is reduced, and the dry etching has the characteristic of anisotropy, so that the problem can be well avoided. Meanwhile, wet etching is not ideal for etching lines below 3 microns, and dry etching can process very accurate RDL line patterns, especially patterns with smaller line width and spacing. Dry etching has become the most dominant process for etching devices at submicron dimensions. However, since it is difficult to achieve sufficient circuit accuracy under the demands of larger wafer size, higher integration and higher throughput, the industry is currently exploring a technology for replacing wafer-level packaging with board-level packaging with high throughput, large size and high accuracy.

However, in the industry, wet processes are mostly adopted for etching the titanium seed layer of the RDL-containing board-level package structure, and dry etching is rarely used. The dry etching of the plate-level titanium seed layer is not mature, so that the problems of uneven etching, low etching efficiency and the like are easily caused; although the wet process has the advantage of easy batch fabrication, some of the chemical solutions involved in the wet process, such as hydrofluoric acid, have adverse effects on the environment, the occupied area of the equipment is large, the production and maintenance processes are complicated, and more importantly, the wet process is not favorable for the fabrication of fine circuits. With the decreasing size of package carriers, the increasing density of circuits and components, and the continuous development of board-level package carriers, the problem of wet process in all these board-level packages is urgently needed to be improved.

It should be noted that the above description of the technical background is only for the sake of clarity and complete description of the technical solutions of the present application and for the understanding of the skilled person, and the technical solutions are not considered to be known to the skilled person merely because they are described in the background section of the present application.

Disclosure of Invention

In view of the above disadvantages of the prior art, an object of the present invention is to provide a device and a method for etching metal in board level package, which are used to solve the problem of poor accuracy of wet etching of a titanium layer in board level package in the prior art.

In order to achieve the above object, the present invention provides a board level package metal etching method, which comprises:

providing a package carrier, wherein the package carrier comprises a titanium layer, a copper layer and a patterned first connecting metal layer, the first connecting metal layer is positioned on the copper layer, and the copper layer is positioned on the titanium layer;

removing the copper layer exposed under the patterned first connecting metal layer through wet etching to expose the titanium layer under the copper layer;

fixing the packaging carrier plate in a reaction cavity;

and introducing a first reaction gas subjected to plasma treatment into the reaction cavity, and performing plasma etching on the titanium layer by using the first reaction gas to remove the exposed titanium layer.

Optionally, the first reaction gas is processed into inductively coupled plasma, capacitively coupled plasma, surface microwave plasma or plasma of any combination of more than one kind in the plasma generating cavity; the plasma generating cavity is isolated from the reaction cavity through an isolating structure, and a plasma channel is arranged on the isolating structure so that first reaction gas subjected to plasma treatment can enter the reaction cavity from the plasma generating cavity.

Optionally, the pressure of the reaction chamber is e ^-6 ～e ^-8 Millibar.

Optionally, the first reactive gas comprises a chlorine-containing gas.

Optionally, the first reaction gas comprises an inert gas or/and a second reaction gas, and the second reaction gas comprises one or more of a gas chemically reacting with the titanium oxide, a corrosive gas, an oxidizing gas or a fluorocarbon compound.

The invention also provides a board-level packaged metal etching device, which is operated by adopting any one of the etching methods, and comprises: the plasma generating device comprises a plasma generating cavity, a reaction cavity, a packaging carrier plate, a fixing structure and a carrying platform;

an isolation structure is arranged between the plasma generation cavity and the reaction cavity, and the isolation structure separates the plasma generation cavity from the reaction cavity; a plasma channel is arranged between the plasma generating cavity and the reaction cavity, and the plasma channel enables first reaction gas which is subjected to plasma treatment by the plasma generating cavity to enter the reaction cavity;

the carrier is arranged in the reaction cavity, and the packaging carrier plate is arranged on the carrier through the fixing structure.

Optionally, the package carrier is divided into a processing area and a fixing area, the processing area is a rectangular area obtained by inwardly reducing the edge of the package carrier by a preset width, and the fixing area is a rectangular frame area surrounding the rectangular area; the fixing structure fixes the packaging carrier plate on the carrying platform through the fixing area.

Optionally, the length of the package carrier is greater than or equal to 400 mm, the width of the package carrier is greater than or equal to 400 mm, and the preset width of the edge of the package carrier, which is inwardly reduced, is 5-30 mm.

Optionally, the plasma channel is annular, a plurality of chips to be etched are arranged on the packaging carrier plate, and the plasma channel is aligned with the plurality of chips to be etched in a direction perpendicular to the packaging carrier plate, so that the first reaction gas after plasma treatment uniformly contacts each chip to be etched.

Optionally, the length of the chip to be etched is 10-20 mm, and the width of the chip to be etched is 10-20 mm.

As described above, the plate-level packaged metal etching device and method of the present invention have the following beneficial effects:

according to the invention, the titanium layer in the board level package is etched by using dry etching, so that the accuracy of processing control is improved, the etching process is shortened, the cost is reduced, the production efficiency is improved, and the environment-friendly concept is met;

according to the invention, the plasma generation cavity and the reaction cavity are separated, so that the treatment efficiency and the treatment uniformity of the first reaction gas are improved, and the influence of the first reaction gas on the packaging support plate is reduced;

the invention arranges a fixed area at the edge of the packaging carrier plate, provides enough fault-tolerant space, and vertically aligns the processing area with the plasma channel to realize the etching uniformity of the packaging carrier plate;

the invention sets the pressure intensity in the reaction chamber, ensures the etching rate and simultaneously realizes the maximization of ion collision.

Drawings

Fig. 1 is a schematic structural view showing a process of removing a titanium oxide layer according to a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram illustrating a process of plasma etching a titanium layer according to an embodiment of the invention.

Fig. 3 is a schematic structural diagram of a titanium layer after plasma etching according to an embodiment of the invention.

Fig. 4 is a schematic structural diagram of an insulating layer according to an embodiment of the invention.

Fig. 5 is a schematic structural diagram illustrating a first pre-plating metal layer according to an embodiment of the invention.

Fig. 6 is a schematic structural diagram of a device for disposing a first pre-plated metal layer according to a first embodiment of the invention.

Fig. 7 is a schematic structural diagram of a resist layer according to an embodiment of the invention.

Fig. 8 is a schematic structural diagram illustrating a first connection metal layer according to an embodiment of the invention.

Fig. 9 is a schematic structural diagram of a copper layer etched according to an embodiment of the present invention.

Fig. 10 is a schematic structural diagram showing a titanium layer etched according to a first embodiment of the invention.

Fig. 11 is a schematic diagram of a midplane level package structure according to an embodiment of the invention.

Fig. 12 is a schematic structural diagram of a metal etching apparatus for mid-board level package according to an embodiment of the present invention.

Fig. 13 is a schematic top view of the processing area and the fixing area of the package carrier board according to the second embodiment of the present invention.

Fig. 14 is a schematic top view illustrating a mounting and fixing structure of a package loading plate according to a second embodiment of the invention.

Fig. 15 is a schematic side view illustrating a mounting structure for a seal carrier plate according to a second embodiment of the present invention.

Description of the element reference numerals

101. Packaging a carrier plate; 1011. a machining area; 1012. a fixed area; 1013. a circular region; 1014. a core board; 1015. an in-board chip; 1016. a sheet metal layer; 1017. a packaging layer; 1018. a solder resist layer; 1019. a solder ball; 1020. a chip slot; 110. an insulating layer; 111. opening the insulating layer; 112. a first pre-plated metal layer; 1121. a titanium layer; 1122. a titanium oxide layer; 1123. a copper layer; 113. a first connection metal layer; 114. a second pre-plated metal layer; 115. a second connection metal layer; 116. a resist layer; 1161. a resist layer opening;

201. a reaction chamber; 202. a plasma generation chamber; 2021. an isolation structure; 2022. a plasma channel; 2023. a plasma electrode; 2024. an air inlet; 2025. a vacuum pump; 203. a sputtering chamber; 2031. sputtering a target material; 2032. sputtering the plasma; 2033. sputtering an electrode; 204. a fixed structure; 205. a stage;

301. a first reactive gas; 302. a gas that chemically reacts with the titanium oxide; 303. a gas that reacts with the titanium; 304. a volatile reactive gas.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

As used herein, the drawings are not intended to be limiting, but are to be construed in an illustrative and exemplary manner. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

Spatially relative terms, such as "under," "below," "lower," "below," "over," "upper," and the like, may be used herein for convenience in describing the relationship of one element or feature to another element or feature illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures.

In the context of this application, a structure described as having a first feature "on" a second feature may encompass embodiments in which the first and second features are formed in direct contact, and may also encompass embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

The first embodiment is as follows:

as shown in fig. 1 to fig. 3, the present invention provides a metal etching method for board level package, the etching method includes:

step 1: providing a package carrier 101, wherein the package carrier 101 comprises a titanium layer 1121, a copper layer 1123 and a patterned first connection metal layer 113, the first connection metal layer 113 is located on the copper layer 1123, and the copper layer 1123 is located on the titanium layer 1121;

step 2: removing the copper layer 1123 exposed under the patterned first connection metal layer 113 by wet etching to expose the titanium layer 1121 under the copper layer 1123;

and step 3: fixing the package carrier 101 in a reaction chamber 201;

and 4, step 4: and introducing the first reaction gas 301 subjected to the plasma treatment into the reaction cavity 201, and performing plasma etching on the titanium layer 1121 by the first reaction gas 301 to remove the exposed titanium layer 1121.

The metal etching method for the board level package according to the present invention will be described in detail with reference to the accompanying drawings, wherein it should be noted that the above sequence does not strictly represent the sequence of the metal etching method for the board level package protected by the present invention, and those skilled in the art can change the sequence according to the actual manufacturing steps.

First, step 1 is performed to provide a package carrier 101, wherein the package carrier 101 includes a titanium layer 1121, a copper layer 1123 and a patterned first connection metal layer 113, the first connection metal layer 113 is located on the copper layer 1123, and the copper layer 1123 is located on the titanium layer 1121.

Then, step 2 is performed, the copper layer 1123 exposed under the patterned first connection metal layer 113 is removed by wet etching, so as to expose the titanium layer 1121 under the copper layer 1123.

Next, step 3 is performed to fix the package carrier 101 in a reaction chamber 201.

Then, step 4 is performed, the first reaction gas 301 after the plasma treatment is introduced into the reaction chamber 201, and the first reaction gas 301 performs plasma etching on the titanium layer 1121 to remove the exposed titanium layer 1121.

According to the invention, the titanium layer 1121 on the package carrier 101 is subjected to dry etching, the dry etching in the embodiment of the invention has anisotropy, and when the titanium layer 1121 is etched, the processing direction can be accurately controlled, so that the influence on the circuit quality due to the side etching of the first connection metal layer 113 is avoided. According to the invention, the titanium layer 1121 on the package carrier 101 is etched by using the dry method, so that a circuit with a high side wall verticality can be obtained, and the titanium layer 1121 with a line spacing within 3 microns can be accurately etched; meanwhile, the dry etching can effectively avoid multi-flow processing of the liquid medicine in wet etching, and the etching process flow of the plate-level packaging substrate containing the RDL (redistribution layer) structure is shortened, so that the investment, maintenance cost, labor cost and time cost of equipment can be reduced, the plant space is saved due to the reduction of the equipment investment, and the plant construction cost is reduced; in addition, if the titanium layer 1121 is etched by a wet method, various chemical liquid systems are often used for etching, the chemical liquid system is added into the titanium layer to be discharged, the process is long, toxic chemical liquid such as hydrofluoric acid is not contained in the titanium layer, and the titanium layer is produced in a non-vacuum environment, so that the titanium layer has a large influence on the environment. In the invention, the titanium layer 1121 is etched by the dry method, so that more environment-friendly and easily-treated process gas can be used, and the titanium layer is etched in a vacuum environment, the gas emission and harmless treatment are simpler than those of the wet etching, and the processing process has little influence on the environment and is more environment-friendly; while exerting many advantages of dry etching, the dry etching of the titanium layer 1121 of the board-level package can obtain more effective etching areas within the same time compared with the wafer-level package generally used for dry etching, thereby greatly improving the production efficiency and shortening the production period.

As an example, the first reactive gas 301 is treated as an inductively coupled plasma, a capacitively coupled plasma, a surface microwave plasma, or a plasma of any one or more combinations within the plasma generating cavity 202; the plasma generation chamber 202 is isolated from the reaction chamber 201 by an isolation structure 2021, and a plasma channel 2022 is disposed on the isolation structure 2021 so that the first reaction gas 301 after plasma treatment can enter the reaction chamber 201 from the plasma generation chamber 202.

Preferably, the first reaction gas 301 is processed into ICP (inductively coupled plasma) by using a radio frequency power supply, and since the ICP plasma has high density and low energy, the ion density and energy can be independently controlled, the electron temperature can be adjusted by adjusting the radio frequency, and a more flexible control means is provided, so that the method is suitable for etching materials with low hardness or thin hardness, such as titanium, monocrystalline silicon and the like.

Specifically, the first reaction gas 301 is introduced into the plasma generation cavity 202, and generates plasma under the action of the induced electric field of the plasma generation cavity 202.

Specifically, the first reaction gas 301 performs high-energy plasma bombardment on the titanium layer 1121 to form a damaged layer, so as to accelerate the reaction of free active radicals in the plasma on the surface of the titanium layer 1121, which is to achieve better anisotropy during etching, so that the plasma etching is more accurate without affecting the non-etched region.

As an example, the chamber pressure of the reaction chamber 201 is e ^-6 ～e ^-8 Millibar.

By setting the cavity pressure of the reaction cavity 201, the reaction ions introduced into the reaction cavity 201 have enough free path to maximize the collision between the reaction ions and the metal atoms of the titanium layer 1121, and simultaneously, the etching rate of the active ions in the effective time is not reduced due to collision rebound among the reaction ions.

In one embodiment, the first reactant gas 301 is introduced at a flow rate of 120 to 180sccm (standard milliliter per minute).

As an example, the first reaction gas 301 includes a chlorine-containing gas.

According to the invention, the gas containing chlorine element which is more suitable for etching the titanium layer 1121 is used as the etching gas, and titanium can be easily subjected to violent reaction with the gas containing the chlorine component even at the temperature of below 0 ℃ to generate titanium tetrachloride and then decomposed into titanium dichloride, so that dry etching can be carried out under the condition of low requirement on reaction conditions, and the convenience of reaction is improved; meanwhile, the titanium layer 1121 is used as a material of a pre-plated metal layer in the invention, and the pre-plated metal layer needs a finer circuit size and form, so that the use of a dry etching method for the titanium layer 1121 in the board level package better meets the precision requirement of the pre-plated metal layer.

Specifically, the first reaction gas 301 reacts with the titanium layer 1121 to generate a volatile gas, including but not limited to TiCl ₄ . Macromolecular gases in the volatile gases generated by the reaction are not easily pumped away by the vacuum pump 2025 as reaction exhaust gases, and can be deposited on the surface of the titanium layer 1121 on the side wall, so that the degree of transverse etching on the titanium layer 1121 on the side wall can be reduced, and an etching form with a higher aspect ratio and higher line precision is formed.

As an example, the first reaction gas 301 includes an inert gas or/and a second reaction gas, and the second reaction gas includes one or more of a gas 302 that chemically reacts with titanium oxide, a corrosive gas, an oxidizing gas, or a fluorocarbon.

According to the invention, the first reaction gas 301 contains the gas which chemically reacts with titanium chloride, so that the naturally formed titanium oxide layer 1122 possibly existing on the titanium surface can be removed, and the etching rate is not influenced; meanwhile, because the gas reacting with the titanium oxide is usually a macromolecular gas, the gas is more easily deposited on the surface of the titanium layer 1121 on the sidewall, and is not exhausted by the vacuum pump 2025 extracting the reaction exhaust gas, so that the degree of lateral etching on the titanium layer 1121 on the sidewall can be reduced, and an etched form with a higher aspect ratio and higher line precision is formed.

In one embodiment, as shown in FIG. 1, the gas chemically reacting with titanium oxide layer 1122 may be BCl ₃ The titanium oxide layer 1122 is decomposed by breaking the chemical bond between titanium and oxygen by bombardment.

In one embodiment, the corrosive gas includes, but is not limited to, cl ₂ 、CO ₂ HCl, HF, etching of titanium by RIE (reactive ion etching).

In one embodiment, the inert gas includes, but is not limited to, he, ne, ar, kr, xe. Specifically, the inert gas effects the etching of the titanium by means of physical bombardment.

In one embodiment, the oxidizing gas includes, but is not limited to, O ₂ Etching of titanium is achieved by RIE (reactive ion etching).

In one embodiment, fluorocarbons include, but are not limited to, CF ₄ 。

Specifically, as shown in fig. 2, when a gas that reacts with the titanium layer 1121, a volatile reaction gas 304 is generated; as shown in fig. 3, after the reaction between the titanium layer 1121 and the gas reacting with the titanium layer 1121 is completed, the volatile reaction gas 304 is extracted from the surface of the package carrier 101 by an exhaust gas collection device such as a vacuum pump 2025.

The following describes a related process of the method for etching the titanium layer 1121 in the board level package structure with reference to a specific manufacturing step of the board level package structure.

First, a first step is performed to prepare a package carrier 101.

Specifically, the package carrier 101 includes a core board 1014, a board metal layer 1016, a board core 1015, a chip slot 1020, and a package layer 1017.

Specifically, the process of preparing the package carrier 101 includes: a core plate 1014 is arranged; a patterned plate metal layer 1016, chip slots 1020 and positioning holes are arranged on the core plate 1014, and the chip slots 1020 penetrate through the whole core plate 1014; arranging an adhesive tape in the chip groove 1020, arranging the inner core plate 1015 in the chip groove 1020, fixing the inner core plate 1015 in the chip groove 1020 by the adhesive tape, attaching the active surface of the inner core plate 1015 to the adhesive tape in a downward manner, and arranging a metal connecting disc on the active surface of the inner core plate 1015; arranging an encapsulation layer 1017 to fill the gap between the inner core plate 1015 and the chip groove 1020 and cover the surface of the inner core plate 1015 so that the inner core plate 1015 is fixed in the chip groove 1020; the package carrier 101 is flipped over so that the active surface of the core die 1015 faces upward, and it is ensured that the metal lands on the core die 1015 are flush with the upper surface of the core die 1014 after the tape is removed.

In one embodiment, the thickness of the die 1015 in a plate is 100 microns.

In one embodiment, the core plate 1015 has a length of 10-20 mm and a width of 10-20 mm.

Preferably, the encapsulation layer 1017 is ABF (ajinomoto film), has good fluidity, heat dissipation property and facilitates subsequent processes.

Specifically, the positioning holes are disposed at the peripheral edges of the core plate 1014, so as to more precisely position the core plate 1014 in the subsequent manufacturing of the stacked layers.

In one embodiment, core board 1014 is a fiberglass cloth resin coated copper clad laminate, and the resin includes, but is not limited to, epoxy resin, phenolic resin, polyester resin.

In one embodiment, plate metal layer 1016 uses copper foil, including but not limited to electrolytic copper and calendered copper.

Then, as shown in fig. 4, a second step is performed to form an insulating layer 110 on the package carrier 101.

In one embodiment, the method of forming the insulating layer 110 is coating including spin coating or slit coating, or vacuum lamination, wherein coating is used for a wet process and vacuum lamination is used for a dry process.

Specifically, the spin coating process includes cooling the package carrier 101, spin coating the insulating layer 110, drying the package carrier 101, cooling the insulating layer 110, exposing the insulating layer 110 using a mask, post-drying the insulating layer 110, developing the insulating layer 110, and post-curing the insulating layer 110 to obtain the insulating layer 110 with the insulating layer opening 111.

Specifically, the slit coating includes removing impurities by plasma, coating the material of the insulating layer 110, vacuum baking the insulating layer 110 by a VCD (vacuum dryer) to discharge moisture and the like on the surface of the insulating layer 110 by negative pressure, pre-baking the insulating layer 110 to pre-cure the insulating layer 110, exposing the insulating layer 110 by using a mask, developing the insulating layer 110, and performing a post-curing process on the insulating layer 110.

Specifically, the vacuum film pasting includes pasting the insulating layer 110 material on the package carrier 101, exposing the insulating layer 110 material with a mask plate, curing the insulating layer 110 with ultraviolet rays, and performing a thermal curing process on the insulating layer 110.

In one embodiment, when the insulating layer 110 is made of a photosensitive material, the insulating layer 110 may be processed to obtain the insulating layer opening 111 by dry etching or wet etching of the above exposure and development; when the insulating layer 110 is made of a non-photosensitive material, the insulating layer 110 may be processed by a laser method to obtain the insulating layer opening 111.

Preferably, after the opening is processed, the plasma Desmear technique (Desmear) or plasma Desmear technique (Descum) is used to remove the contamination and the smear on the surface of the insulating layer 110 and the surface of the opening, so that the titanium layer 1121 can have better adhesion in the insulating layer 110 and the opening 111 of the insulating layer when the first pre-plated metal layer 112 is fabricated subsequently.

In one embodiment, the insulating layer 110 material includes, but is not limited to, ABF (ajinomoto build-up film) and positive photoresist. The positive photoresist is easy to dissolve in organic solvents such as ether, ester, ketone and the like, has higher resolution, can obtain submicron-grade patterns, and is suitable for application in board-level packaging for designing lines with higher precision.

In one embodiment, the insulating layer 110 is 5-10 microns thick, without limitation.

Next, as shown in fig. 5, a third step is performed to dispose a titanium layer 1121 and a copper layer 1123 on the surfaces of the insulating layer 110 and the insulating layer opening 111, wherein the copper layer 1123 is located on the titanium layer 1121.

Preferably, the titanium layer 1121 and the copper layer 1123 are disposed on the surfaces of the insulating layer 110 and the insulating layer opening 111 by a PCD (physical vapor deposition) method, and the thickness controllability and the repeatability of the titanium layer 1121 and the copper layer 1123 obtained by PCD are good, the application range is wide, and the bonding force with the package carrier 101 is good.

Specifically, before the titanium layer 1121 and the copper layer 1123 are disposed, the package carrier 101 is evacuated to exhaust the water vapor and the remaining volatile gases on the package carrier 101, so as to avoid affecting the board surface of the package carrier 101.

In one embodiment, the exhaust method includes, but is not limited to, vacuum pumping or introducing a gas such as nitrogen that does not chemically react with the package carrier 101.

Specifically, the vacuum pressure may be less than 10 during vacuum pumping ^-2 And (4) supporting.

Preferably, the exhaust temperature may be 100 ℃ to 150 ℃ and the time may be 0.5 to 1 hour.

Specifically, after exhausting, the package carrier 101 is placed in a vacuum chamber for plasma etching, which is used to clean the surface of the package carrier 101 and remove the oxide remaining in the process, and is used to perform micro etching on the surface of the package carrier 101 and the opening 111 of the insulating layer to activate the surface, so as to enhance the adhesion of the subsequent sputtered titanium layer 1121.

In one embodiment, the vacuum pressure within the vacuum chamber may be 10 ^-2 ～10 ^-3 And (4) supporting.

In one embodiment, the gas used for plasma etching comprises Ar, O ₂ 、N ₂ 、H ₂ Or CF ₄ 。

Preferably, as shown in fig. 6, a titanium layer 1121 is disposed on the insulating layer 110 and the opening 111 of the insulating layer by ion sputtering.

Specifically, the package carrier 101 is disposed on the carrier 205 through the fixing structure 204, the two sputtering electrodes 2033 are disposed under the package carrier 101 and at the upper end of the sputtering chamber 203, respectively, the sputtering electrode 2033 at the upper end of the sputtering chamber 203 is disposed with the sputtering target 2031, the two sputtering electrodes 2033 act on the sputtering target 2031 between the sputtering electrodes 2033 through the formed electric field to form the sputtering plasma 2032 to sputter onto the package carrier 101, so as to obtain the titanium layer 1121.

In one embodiment, the plasma during ion sputtering may be formed by an ion gun, CCP (capacitively coupled plasma), ICP (inductively coupled plasma), or a combination of any one or more of the foregoing.

In one embodiment, the current power for ion sputtering may be 1-15kW, the process gas is typically Ar, and the heating temperature may be 100-150 ℃.

In one embodiment, a copper layer 1123 is disposed on the titanium layer 1121 by means of PVD (physical vapor deposition).

Preferably, the copper layer 1123 is thicker than the titanium layer 1121, and the first pre-plated metal layer 112 consisting of the copper layer 1123 and the titanium layer 1121 may have a thickness of 50 nm-500 nm with a deviation of less than 5% in thickness.

Then, step four is performed to dispose the first connection metal layer 113 on the copper layer 1123.

Specifically, as shown in fig. 7, a resist layer 116 is provided on the first pre-plated metal layer 112, and then the resist layer 116 is patterned; as shown in fig. 8, a first connection metal layer 113 is provided on the patterned resist layer 116 to fill the space between the resist layers 116, and then the resist layers 116 are removed.

In one embodiment, the resist layer 116 and its patterning are processed by film pasting, spin coating or slit coating to obtain the resist layer opening 1161, which is similar to the preparation method of the insulating layer 110 and will not be described herein again.

In one embodiment, the resist layer 116 material includes, but is not limited to, a polymer adhesive.

Preferably, the first connecting metal layer 113 is provided by high speed electroplating, which has higher electroplating efficiency and mass transfer, and can produce a coating layer with higher quality and better uniformity.

Preferably, the current density for high speed plating can be 5-10ASD (amperes per square decimeter).

Specifically, the electroplating method comprises washing the surface to be electroplated with high-pressure water, pickling the surface to be electroplated with high-pressure water, electroplating the surface to be electroplated, washing the surface after electroplating with water, and drying the surface after electroplating.

In one embodiment, the removal of the resist layer 116 may be performed by wet etching with a stripping solution, dry ashing or plasma etching, and the plasma etching may use O ₂ 、N ₂ 、CF ₄ Or a combination of any one or more of the above.

Preferably, the ratio of the thickness of the first connection metal layer 113 to the line width is 1:1.

preferably, the first connection metal layer 113 has a thickness deviation <5%, and the thickness may be 5-10 μm.

Preferably, the material of the first connection metal layer 113 is copper.

Next, step five is performed, as shown in fig. 9, the copper layer 1123 is etched, and as shown in fig. 10, the titanium layer 1121 is etched.

In one embodiment, the copper layer 1123 is removed using a wet etch.

In one embodiment, the reagent used for wet etching may be aqueous alkali metal hydroxide, naHCO ₃ Or any one of the above reagents with H ₂ O ₂ The alkali metal hydroxide aqueous solution may be NaOH, KOH, or the like.

In one embodiment, the reagent used for wet etching may be H ₂ SO ₄ And H ₂ O ₂ Mixture of (2), weak acid and H ₂ O ₂ A mixture of (a).

Specifically, the method of removing the titanium layer 1121 is as described above, and is not repeated herein, so that a first layer RDL (redistribution layer) on the package carrier 101 is obtained, as shown in fig. 11, the above steps may be repeated to obtain a second pre-plating metal layer 114 and a second connection metal layer 115, where an enlarged view of a white square portion in fig. 11 is shown in fig. 10.

In one embodiment, the above steps may be repeated as many times as necessary to obtain a multilayer RDL structure.

Then, step six is performed to form the solder resist layer 1018 and its opening.

Specifically, the forming method comprises the following steps: and pasting a solder mask layer 1018 material, exposing the solder mask layer 1018 by using a mask plate, developing the solder mask layer 1018, and performing a post-curing process on the solder mask layer 1018 to obtain the solder mask layer 1018 with an opening, wherein the opening exposes the second connection metal layer 115 in the uppermost RDL.

Finally, step seven is performed to form solder balls 1019 on the second connection metal layer 115 exposed by the openings of the solder mask layer 1018, so as to obtain the board-level package structure shown in fig. 11.

In one embodiment, a solder ball 1019 is formed on the solder paste or the solder paste, one end of the solder ball 1019 is electrically connected to the second connection metal layer 115, and the other end passes through the solder mask layer 1018 to be exposed on the surface of the package structure.

In one embodiment, the solder balls 1019 include, but are not limited to, C4 (controlled collapse chip attach) formed solder balls 1019.

Preferably, the spacing between the solder balls 1019 is greater than the spacing between the metal lands on the active side of the die 1015 on the board.

Example two:

as shown in fig. 12, the present invention provides a board-level packaged metal etching apparatus, which is operated by using any one of the etching methods in the first embodiment, and includes: a plasma generation cavity 202, a reaction cavity 201, a package carrier 101, a fixed structure 204 and a carrier 205;

an isolation structure 2021 is arranged between the plasma generation cavity 202 and the reaction cavity 201, and the isolation structure 2021 separates the plasma generation cavity 202 from the reaction cavity 201; a plasma channel 2022 is arranged between the plasma generation cavity 202 and the reaction cavity 201, and the plasma channel 2022 enables the first reaction gas 301 which is subjected to plasma treatment by the plasma generation cavity 202 to enter the reaction cavity 201;

the carrier 205 is disposed in the reaction chamber 201, and the package carrier 101 is disposed on the carrier 205 through the fixing structure 204.

According to the invention, the isolation structure 2021 is arranged between the plasma generation cavity 202 and the reaction cavity 201, so that the plasma generation cavity 202 and the reaction cavity 201 are separated, and on one hand, the plasma is generated more sufficiently, and the generation efficiency is higher; and on the other hand, the pollution and damage to the package carrier 101 during the process of generating the plasma are reduced as much as possible.

Specifically, the first reaction gas 301 enters the plasma generation cavity 202 from the gas inlet 2024 to perform plasma treatment, so as to obtain a plasma gas 302 which chemically reacts with titanium oxide and a gas 303 which reacts with titanium, wherein the gas 303 which reacts with titanium is one or more of an inert gas, a corrosive gas, an oxidizing gas or a fluorocarbon which are subjected to plasma treatment.

Specifically, after being subjected to plasma treatment in the plasma generation chamber 202, the first reaction gas 301 enters the reaction chamber 201 through the plasma channel 2022 on the isolation structure 2021, and reacts with the titanium layer 1121, and a vacuum pump 2025 is disposed at an outlet of the reaction chamber 201 for extracting and exhausting the volatile reaction gas 304 generated by the reaction.

Preferably, the warpage of the package carrier 101 is less than ± 7 mm.

Specifically, the warpage of the board is controlled by adjusting the three-dimensional position of the carrier 205 and the manufacturing process of the package carrier 101.

Specifically, the plasma electrode 2023 is respectively disposed outside the plasma generating cavity 202 and under the package carrier 101, and is used for adjusting the introduction direction of the plasma, so as to accurately etch the portion to be etched on the package carrier 101.

As an example, as shown in fig. 13-15, the package carrier 101 is divided into a processing area 1011 and a fixing area 1012, the processing area 1011 is a rectangular area obtained by inwardly reducing the edge of the package carrier 101 by a predetermined width, and the fixing area 1012 is a rectangular frame area surrounding the rectangular area; the fixing structure 204 fixes the package carrier 101 on the carrier 205 through the fixing area 1012.

In particular, the fixing structure 204 may be a clamp for clamping the package carrier 101.

By arranging the fixing area 1012 on the periphery of the package carrier 101, the invention provides enough fault-tolerant space on the premise of ensuring that the package carrier 101 has enough effective processing area 1011, and prevents the clamping tool from blocking the part to be etched from being etched.

As an example, the length of the package carrier 101 is greater than or equal to 400 mm, the width of the package carrier 101 is greater than or equal to 400 mm, and the predetermined width of the package carrier 101 that is reduced inward from the edge is 5-30 mm.

According to the invention, through setting the size of the fixed area 1012, the accuracy of a fault-tolerant space is further improved and the maximization of the effective processing area 1011 is further improved.

As an example, the plasma channel 2022 is annular, a plurality of chips to be etched are disposed on the package carrier 101, and the plasma channel 2022 is aligned with the plurality of chips to be etched in a direction perpendicular to the package carrier 101, so that the first reactive gas 301 after plasma treatment uniformly contacts each chip to be etched.

According to the invention, the plurality of chips to be etched are vertically aligned with the plasma channel 2022, so that the first reaction gas 301 introduced into the plasma channel 2022 can uniformly contact the chips to be etched at an equal speed, the etching rates of the chips to be etched are equal, a more uniform etched surface is obtained, and the fineness of an etched line is improved.

In one embodiment, 4 circular areas 1013 are provided, the circular areas 1013 are evenly distributed in the processing area 1011, each circular area 1013 has a diameter of 200 mm, and the chips to be etched are disposed in the circular areas 1013.

Preferably, the interval between each chip to be etched is greater than 5 mm, so as to avoid warpage of the board surface of the package carrier 101 caused by excessive local stress due to excessive concentration of the chips to be etched in the subsequent process, and ensure the heat dissipation efficiency between the chips to be etched.

As an example, the length of the chip to be etched is 10-20 mm, and the width of the chip to be etched is 10-20 mm.

In conclusion, the device and the method for etching the metal in the board level package can etch the titanium layer in the board level package by using dry etching, improve the accuracy of processing control, shorten the etching process, reduce the cost, improve the production efficiency and accord with the environmental protection concept; meanwhile, the plasma generation cavity is separated from the reaction cavity, so that the treatment efficiency and the treatment uniformity of the first reaction gas are improved, and the influence of the first reaction gas on the packaging support plate is reduced; in addition, a fixed area is arranged at the edge of the packaging carrier plate, so that enough fault-tolerant space is provided, and the processing area is vertically aligned with the plasma channel, so that the etching uniformity of the packaging carrier plate is realized; and finally, setting the pressure intensity in the reaction chamber, and realizing the ion collision maximization while ensuring the etching rate.

Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A metal etching method for board level packaging is characterized by comprising the following steps:

fixing the packaging carrier plate in a reaction cavity;

2. The method of claim 1, wherein the first reactive gas is processed into inductively coupled plasma, capacitively coupled plasma, surface microwave plasma or any combination of more than one plasma in the plasma generating chamber; the plasma generating cavity is isolated from the reaction cavity through an isolating structure, and a plasma channel is arranged on the isolating structure so that first reaction gas subjected to plasma treatment can enter the reaction cavity from the plasma generating cavity.

3. The method of claim 1, wherein the chamber pressure of the reaction chamber is e ^-6 ～e ^-8 Millibar.

4. The method of claim 1, wherein the first reactive gas comprises a chlorine-containing gas.

5. The method of claim 4, wherein the first reactive gas comprises an inert gas or/and a second reactive gas, and the second reactive gas comprises one or more of a gas chemically reactive with titanium oxide, a corrosive gas, an oxidizing gas, and a fluorocarbon.

6. A board level packaged metal etching device, characterized in that the etching device is operated using the etching method of any one of claims 1 to 5, and the etching device comprises: the plasma generating device comprises a plasma generating cavity, a reaction cavity, a packaging carrier plate, a fixing structure and a carrying platform;

7. The device of claim 6, wherein the package carrier is divided into a processing area and a fixing area, the processing area is a rectangular area obtained by inwardly reducing the edge of the package carrier by a preset width, and the fixing area is a square frame area surrounding the square area; the fixing structure fixes the packaging carrier plate on the carrying platform through the fixing area.

8. The apparatus of claim 7, wherein the length of the package carrier is greater than or equal to 400 mm, the width of the package carrier is greater than or equal to 400 mm, and the predetermined width of the package carrier that is reduced inward from the edge of the package carrier is 5-30 mm.

9. The device of claim 6, wherein the plasma channel is annular, the package carrier is provided with a plurality of chips to be etched, and the plasma channel and the plurality of chips to be etched are aligned in a direction perpendicular to the package carrier, so that the first reactive gas after plasma treatment uniformly contacts each chip to be etched.

10. The plate-level packaged metal etching device according to claim 9, wherein the length of the chip to be etched is 10-20 mm, and the width of the chip to be etched is 10-20 mm.