Ceramic roughening method

Abstract

The application provides a ceramic roughening method, which comprises the following steps: configuring plasma gas according to ceramic characteristics, and filling the plasma gas into a ceramic substrate with an initial roughness; adjusting process parameters, so that active plasma ionized by high-frequency glow discharge reaction of the plasma gas reacts with target components in the ceramic substrate with the initial roughness, the reaction rate of the active plasma and different oxidation components in the ceramic substrate is different, and a ceramic substrate with a target roughness is obtained; wherein the target roughness is greater than the initial roughness. The embodiment of the present application obtains a good and uniform ceramic substrate surface, the whole surface is a honeycomb-shaped microporous structure, the surface does not affect the performance of the substrate itself, increases the bonding area, and has good adhesion.

Description

Technical Field

[0001] This application relates to the field of semiconductor test substrate technology, specifically to LTCC low-temperature co-fired ceramic substrate hybrid circuit substrate technology, and more specifically to a ceramic roughening method. Background Technology

[0002] During semiconductor wafer testing, the corresponding ceramic substrate requires extremely high flatness. The ceramic substrate needs to undergo meticulous grinding and polishing to meet these flatness requirements. However, the polished ceramic surface becomes mirror-smooth, resulting in very weak adhesion when applying adhesives or plating copper on the smooth substrate, significantly impacting the application process. Therefore, roughening the smooth ceramic surface is necessary.

[0003] Depending on the manufacturing process, there are various types of substrates, including LTCC ceramic substrates. After firing, LTCC ceramic substrates exhibit warping and significant surface roughness, making them unsuitable for direct application in thin-film circuitry (TFT) processes to create more precise wiring layers. Therefore, further grinding and polishing of the LTCC ceramic substrate is necessary. However, the surface roughness of the polished LTCC ceramic substrate is small, resulting in poor adhesion between the ceramic and subsequent PVD coatings and dielectric layers. Thus, surface roughening treatment of the LTCC ceramic is required.

[0004] Common roughening methods include etching with hydrofluoric acid (HF) and etching with sulfuric acid (H2SO4) solution. Whether by dissolving the ceramic substrate surface or reacting chemically with the ceramic surface components, these two solutions are hazardous chemicals. Due to their corrosiveness and toxicity, operations must be carried out under strictly safe conditions, and wastewater treatment according to usage restrictions is required, making the process cumbersome. With increasingly stringent environmental impact assessment requirements, the volatile corrosiveness of these two solutions leads to even higher process requirements, and more stringent usage regulations and wastewater discharge requirements. Furthermore, since both solutions are hazardous chemicals, improper control resulting in excessive roughening can not only reduce coating adhesion but also damage the structure, ultimately leading to poor roughening of the ceramic substrate surface.

[0005] Therefore, a new ceramic roughening treatment scheme is needed. Summary of the Invention

[0006] In view of this, embodiments of this specification provide a ceramic roughening method, applied to the semiconductor testing LTCC ceramic substrate process.

[0007] The embodiments in this specification provide the following technical solutions:

[0008] This specification provides an embodiment of a ceramic roughening method, the ceramic roughening method comprising:

[0009] Plasma gas is configured according to the ceramic properties, and the plasma gas is filled into the ceramic substrate with initial roughness.

[0010] By adjusting the process parameters, the active plasma ionized by the plasma gas through high-frequency glow discharge reacts with the target components in the ceramic substrate with the initial roughness. The reaction rate of the active plasma with different oxide components in the ceramic substrate is different, resulting in a ceramic substrate with the target roughness; wherein the target roughness is greater than the initial roughness.

[0011] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least:

[0012] Different plasma gases are prepared for different ceramic substrates. The plasma gas is filled into the plasma equipment, heated and subjected to high-frequency glow discharge, ionizing active plasma to react with the target components on the substrate surface. Due to the different oxide compositions of the ceramic substrates and the inevitable crystallization during the firing process, different structures and sizes of grains are produced. Different grain compositions react with the active plasma at different rates. By controlling the process parameters of the active plasma, the desired surface roughness of the ceramic can be achieved, such as a roughness of about 0.4 μm, to obtain a good and uniform roughened surface with an overall honeycomb-like microporous structure. This surface does not affect the performance of the substrate itself, increases the bonding area, and has good adhesion. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a roughened ceramic substrate according to this application;

[0015] Figure 2 This is a flowchart of a ceramic roughening process described in this application;

[0016] Figure 3 This is a schematic diagram showing the effect of roughening the surface of the ceramic substrate before and after in this application. Detailed Implementation

[0017] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0018] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0020] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0022] Semiconductor wafer testing requires the attachment of multiple ceramic substrates. Depending on the manufacturing process, the types of substrates include low temperature co-fired multilayer ceramic substrates (LTCC), high temperature co-fired multilayer ceramic substrates (HTCC), direct bonded copper substrates (DBC), and direct copper plated substrates (DPC).

[0023] Currently, LTCC ceramic substrates suffer from warping and high surface roughness after firing, making it impossible to directly apply thin-film circuitry (TFT) to create more precise wiring layers. Therefore, further grinding and polishing of the LTCC ceramic substrate is necessary. However, the low surface roughness after polishing results in poor adhesion between the ceramic and subsequent PVD coatings and dielectric layers. Thus, surface roughening treatment of the LTCC ceramic is required.

[0024] Current technologies for roughening multilayer ceramic substrates typically employ hydrofluoric acid (HF) etching and sulfuric acid (H₂SO₄) solution corrosion reactions. When using sulfuric acid (H₂SO₄) to etch the material surface, the sulfuric acid reacts chemically with the components of the ceramic surface. Due to factors such as concentration polarization in the solution reaction, the roughness uniformity is poor, resulting in irregular pits and cracks, leading to poor roughening effects. Since sulfuric acid is a Class III controlled toxic chemical, the roughening environment has strict requirements, necessitating reaction and wastewater treatment according to usage restrictions, making the process cumbersome. Alternatively, hydrofluoric acid (HF) etching dissolves the glassy phase on the ceramic surface to form a rough surface and improve adhesion. However, hydrofluoric acid itself is a hazardous chemical; its volatility, corrosiveness, and toxicity severely restrict its use, and it also requires reaction and wastewater treatment according to usage regulations.

[0025] With stricter environmental impact assessment requirements, the use of these two roughening solutions has become more regulated, resulting in higher process requirements. Furthermore, improper control during the roughening process using these solutions can lead to reduced coating adhesion and, in severe cases, structural damage. This makes the roughening process uncontrollable and carries a high risk.

[0026] Research has found that using conventional plasma etching methods on ceramic substrates can lead to the formation of new solidified material during the reaction process, thereby preventing further reaction and making it impossible to use conventional plasma etching methods to react on the surface of the ceramic substrate.

[0027] In light of this, the inventors discovered that the presence of crystallization during the firing process of ceramic substrates leads to the generation of grains with different structures and sizes, resulting in different structures in different ceramic substrates. However, they also discovered that the reaction rates of plasma gas with different oxides vary. Ceramic components exhibit anisotropy; the reaction rates between active plasma and the components in the ceramic substrate differ, as do the phases of the reaction products. Some structures exhibit high levels of micro-etching, while others show low levels of micro-etching or are not etched at all. Some reaction products are volatile and easily removed by vacuum adsorption. Based on this, by controlling the degree of micro-etching of different components through process parameters, uneven pits are created on the substrate surface, thereby allowing for precise control of the ceramic surface roughness.

[0028] The embodiments in this specification, without affecting the performance of the substrate itself (flatness, electrical properties, mechanical properties, airtightness, etc.), can efficiently and stably roughen ceramic substrates by controlling plasma concentration, process time, and different reactive gas compositions.

[0029] Based on this, this specification provides a novel ceramic roughening scheme. Specifically, a plasma gas is adapted to the ceramic properties, and the plasma gas is used to fill a ceramic substrate with an initial roughness. Process parameters are adjusted so that the active plasma, ionized by a high-frequency glow discharge reaction, reacts with the target components in the initially roughened ceramic substrate. The reaction rate between the active plasma and different oxide components in the ceramic substrate varies, resulting in a ceramic substrate with a target roughness. The target roughness is greater than the initial roughness. The surface of the ceramic substrate needs to be cleaned before each step of the reaction between the ceramic substrate and the plasma gas.

[0030] The substrate surface with this target roughness will not have pits or cracks, and will have an overall honeycomb-like microporous structure, thus obtaining a good and uniform roughened surface for the ceramic substrate. This not only improves the effect of ceramic surface roughening treatment, but also enables roughening operations to be performed in a safe and convenient environment, solving various limitations and defects in the application scenarios or etching solutions of existing ceramic surface roughening technologies.

[0031] According to the experimental results, the substrate with the target roughness is a ceramic substrate with a roughness of approximately 0.4 μm. The surface of the substrate has a honeycomb-like microporous structure, and the film substrate has good bonding performance.

[0032] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0033] like Figure 2 For example, an embodiment of this specification provides a ceramic roughening method, which includes steps S210 to S220. Step S210 involves adapting a plasma gas according to the ceramic properties and filling the substrate with the initial roughness using the plasma gas. Step S220 involves adjusting process parameters, allowing the plasma gas to react with the target components in the initially roughened substrate using active plasma generated by a high-frequency glow discharge reaction. The reaction rate between the active plasma and different oxide components in the ceramic substrate varies, resulting in a ceramic substrate with a target roughness; wherein the target roughness is greater than the initial roughness. In some embodiments, the initially roughened ceramic substrate is smooth (roughness <0.05 μm).

[0034] Studies have found that common low-temperature co-fired ceramic substrates (LTCCs) are typically composites of crystals and glass, with their main components generally being common oxides such as Al₂O₃, SiO₂, CaO, MgO, and ZnO. The Si-O bond energy (4.25 eV) is relatively low, resulting in a fast chemical reaction rate with corrosive halogen gases; the Al-O bond energy (76.9 eV) is relatively high, leading to a slower chemical reaction rate with corrosive halogen gases; and the bond energies of other materials such as Ca-O are even higher.

[0035] Specifically, in step S210, the plasma gas is adapted according to the ceramic properties. Since the reaction rate of the plasma gas with different oxides varies, the plasma gas is adapted to the ceramic substrate to be roughened based on the general composition of the oxides in the ceramic substrate. For example, the bond energies of oxide chemical bonds vary; Si-O has lower bond energies and reacts faster with halogen-based corrosive gases, while Al-O, with relatively higher bond energies, reacts slower. Other oxides, such as Ca-O, have even higher bond energies and react even slower with halogen-based corrosive gases. Therefore, the corresponding plasma gas is adapted according to the ceramic properties to ensure rapid reaction between the active plasma and the target oxide, and to remove some volatile reaction products through vacuum adsorption.

[0036] Then, in step S210, after adapting the ceramic properties to the plasma gas, the plasma gas is filled into the ceramic substrate with the initial roughness. In some embodiments, the ceramic substrate to be roughened is smooth, with an initial roughness of <0.05 μm.

[0037] Based on this, by controlling the plasma concentration and process time, different reactive gas compositions can achieve efficient, stable, safe, and convenient ceramic roughening.

[0038] A ceramic substrate is placed in a plasma device, filling the cavity with reactive gas, i.e., plasma gas. In step S220, plasma gases of different compositions are adapted according to the characteristics of the ceramic. By adjusting process parameters, the plasma reacts with the target oxide in the ceramic substrate. The reaction rate between the active plasma and different oxide components in the ceramic substrate varies. The plasma is controlled to achieve a high degree of micro-etching of some target components in the ceramic substrate, and the reaction products are volatile and can be cleaned by vacuum adsorption, while the remaining components have a low degree of micro-etching or are not corroded at all. Therefore, by adjusting the process parameters of the reaction in the plasma device, the plasma ionized from the plasma gas reacts with the target components in the ceramic substrate, causing the surface of the initially rough ceramic substrate to form a honeycomb-like microporous morphology after the reaction, thereby obtaining a ceramic substrate with the target roughness, such as a target roughness of about 0.4 μm, achieving the effect of roughening the ceramic.

[0039] like Figure 3The surface effect of the ceramic substrate before processing in Example A is that it has a low roughness. Figure 3 Example B shows the surface effect of the ceramic substrate after treatment by the present invention, and the improvement in roughness before and after comparison is significant.

[0040] In some embodiments, the ceramic substrate includes a crystalline phase, a glassy phase, and a small number of pores.

[0041] Common low-temperature co-fired ceramic substrates (LTCCs) are typically composites of crystals and glass. The ceramic substrate composition is generally multiphase, including a crystalline phase, a glassy phase, and a small amount of gas.

[0042] Among them, the microcrystalline glass system: microcrystalline glass is a composite material consisting of a large number of tiny crystals and a small amount of residual glass phase, which is obtained by controlled crystallization of a glass of a certain composition.

[0043] In some embodiments, the ceramic system includes, but is not limited to, silicate-based, aluminosilicate-based, borosilicate-based, borate-based, and phosphate-based systems. Specifically, glass-ceramics can generally be classified into five major categories based on their basic glass composition: silicate systems, aluminosilicate systems, borosilicate systems, borate systems, and phosphate systems.

[0044] For example, the interior of CaO-B2O3-SiO2 system LTCC ceramic substrates generally contains oxides such as CaO, SiO2, B2O3, Al2O3, and MgO. Through liquid phase sintering, wollastonite, calcium borite, quartz and other crystalline phases are generated in the glass phase, and a small amount of pores are also included.

[0045] Among them, the glass + ceramic composite system involves adding a low-melting-point glass phase to the ceramic. During sintering, the glass softens and its viscosity decreases, thereby lowering the sintering temperature. The glass mainly consists of various crystallized glasses, and the ceramic filler phase mainly includes Al2O3, SiO2, cordierite, mullite, etc.

[0046] For example, alumina-based LTCC ceramic substrates are made by adding a low-melting-point glass phase to alumina ceramics and sintering it. The glass is usually crystallized glass, and other crystalline phases and residual glass phases will precipitate during sintering.

[0047] In some embodiments, different ceramic properties are configured with plasma gases of different compositions, including fluorine-containing gases, chlorine-containing gases, and other halogenated gases. These include, but are not limited to, carbon tetrafluoride, sulfur hexafluoride, octafluoropropane, chloroform, tetrachlorosilane, hydrogen bromide, boron trichloride, carbon tetrachloride, and chlorine.

[0048] In the embodiments of this specification, carbon tetrafluoride is used as an example on a CaO-B2O3-SiO2 based LTCC ceramic substrate. Another example is carbon tetrafluoride and chlorine gas on an alumina-based LTCC ceramic substrate. See the detailed description below for further details.

[0049] In some embodiments, the active plasma reacts with the pores, glass phase, and crystalline phase in the ceramic substrate at different rates and with different reactant phases.

[0050] Specifically, the plasma gas ionizes into active plasma, which reacts with pores, the glassy phase, and the crystalline phase in the ceramic substrate at different rates and with different reactant phases. For example, when reacting with a microcrystalline exfoliated LTCC ceramic substrate, CF4 preferentially etches open pores on the surface of the ceramic substrate and the glassy phase within the substrate, forming a preliminary micro-etching state. Then, after CF4 and the glassy phase have been etched, some grain boundaries are etched, loosening the grains and forming a micro-time state. Subsequently, CF4 ionizes into F, which reacts with Si-O in the ceramic components with lower bond energy, causing it to decompose and generate SiF gas. As another example, when reacting with a glass + ceramic composite LTCC ceramic substrate, CF4 preferentially etches open pores on the surface of the ceramic substrate and the glassy phase within the substrate. After CF4 etches the surface glassy phase, the internal crystalline phases are etched and loosened.

[0051] In some embodiments, the ceramic roughening method further includes: adjusting the process sequence and number of times the components in the plasma gas are introduced.

[0052] In conjunction with the above embodiments, the plasma gas component in some embodiments includes CF4, while in others it includes both CF4 and Cl2. Specifically, for example, in the reaction with a microcrystalline glass-based LTCC ceramic substrate, CF4 is used as the plasma gas component. During the reaction, CF4 is first introduced once to preferentially etch the open pores on the ceramic substrate surface and the glass phase within the substrate. After cleaning the etched surface, CF4 is introduced again to form a micro-etched state. CF4 is then introduced again, ionizing to produce active plasma that reacts with the low-bond-energy Si-O in the ceramic components, causing it to decompose and generate SiF gas, which is then removed by the vacuum system. At this point, a low degree of roughening is formed on the substrate surface. The etched surface is cleaned, and CF4 is introduced again to react with the residual Si-O on the ceramic surface until the surface Si is completely removed. Therefore, during the reaction, CF4 is introduced multiple times to gradually react with the ceramic components, ultimately resulting in a honeycomb-like microporous structure on the surface of the ceramic substrate.

[0053] For example, in the reaction with a glass-ceramic composite LTCC ceramic substrate, CF4 is first introduced, preferentially etching the open pores on the surface of the ceramic substrate and the glass phase inside the substrate. After cleaning the etched surface, CF4 is introduced again. After the glass phase on the surface is etched, the internal crystal phases are etched and loosened. After cleaning the etched surface again, CF4 is turned off, and Cl2 is introduced, causing Cl2 to ionize and form various neutral groups or Cl... - Cl -The CF4 continues to react with Al-O in the ceramic component, causing it to decompose and generate AlCl gas, which is then removed by the vacuum system. At this point, a low degree of roughening forms on the substrate surface. After cleaning the etched surface, Cl2 is introduced again, allowing it to continue reacting with Al-O in the ceramic component to decompose and generate AlCl gas. Ultimately, the target alumina grains on the ceramic substrate surface are etched, while the remaining grains remain unetched. Therefore, during the reaction process, not only is CF4 introduced in multiple stages, but Cl2 is also gradually introduced to react with the ceramic component, resulting in an overall honeycomb-like microporous structure on the surface of the ceramic substrate.

[0054] In some embodiments, adjusting process parameters includes at least one of the following: adjusting the concentration of plasma gas; adjusting the pressure of plasma gas; adjusting the process sequence of each component in plasma gas; adjusting the number of times plasma gas is introduced; adjusting the reaction voltage; and adjusting the reaction time.

[0055] In conjunction with the above embodiments, for example, when reacting with a microcrystalline glass-based LTCC ceramic substrate, after the ceramic substrate is placed on the reaction platform and the equipment is evacuated, 10-100 sccm of CF4 is first introduced and stabilized at 3 Pa, with an input ignition voltage of approximately 50 V, and the processing time is 5 min; the ceramic surface forms a preliminary etched state; after cleaning the etched surface, 10-100 sccm of CF4 is continued to be introduced and stabilized at 3 Pa, with an input ignition voltage of approximately 80 V, and the processing time is 15 min; this facilitates grain boundary corrosion during plasma etching; the etched surface is then cleaned to form a micro-etched state; subsequently, 10-100 sccm of CF4 is continued to be introduced and stabilized at 3 Pa, with an input ignition voltage of approximately 100-150 V, and the processing time is 15 min; the substrate surface forms a low degree of roughening; the etched surface is then cleaned again; 100-150 sccm of CF4 is introduced... CF4 is applied and regulated to 5 Pa. Then, an ignition voltage of about 300 V is applied to allow F ions to continue reacting with the residual Si-O on the ceramic surface, achieving a state where the Si on the surface is completely removed. The etched surface is then cleaned. Finally, the target silicon dioxide grains on the surface are etched, while the remaining grains are not etched, achieving the purpose of roughening.

[0056] For example, in the reaction with a glass + ceramic composite LTCC ceramic substrate, after the ceramic substrate is placed on the reaction platform and the equipment is evacuated, 10-100 sccm of CF4 is first introduced and the voltage is stabilized at 3 Pa. Then, an ignition voltage of approximately 50 V is applied, and the processing time is 5 minutes. A preliminary micro-etched state is formed on the ceramic surface. After cleaning the etched surface, 50-100 sccm of CF4 is introduced again and the voltage is stabilized at 3 Pa. An ignition voltage of approximately 80 V is applied, and the processing time is 15 minutes. After the glass phase on the ceramic surface is etched, the internal crystal phases begin to be etched and loosened. After cleaning the etched surface and forming a micro-etched state, the CF4 inlet is closed, 100-150 sccm of Cl2 is introduced and the voltage is stabilized at 5 Pa. Then, an ignition voltage of approximately 100-150 V is applied, and a low degree of roughening is formed on the ceramic substrate surface. After cleaning the etched surface, 150-200 sccm of CF4 is introduced again. Cl2 is applied and the voltage is stabilized to 5 Pa. Then, an ignition voltage of about 300 V is applied to allow Cl2 to continue reacting with Al-O in the ceramic components, causing it to decompose and generate AlCl gas. Finally, the target alumina grains on the ceramic surface are etched, while the remaining grains are not etched, thus achieving the purpose of coarsening.

[0057] Therefore, the concentrations of the plasma gas reacting on the ceramic substrate are 10-100 sccm, 50-100 sccm, 100-150 sccm, and 150-200 sccm, and the pressure of the plasma gas is stabilized at 3 Pa or 5 Pa, respectively.

[0058] In some embodiments, the process sequence for adjusting the components of the plasma gas includes introducing carbon tetrafluoride and chlorine gas into the plasma device respectively, with carbon tetrafluoride introduced before chlorine gas.

[0059] In conjunction with the above embodiments, CF4 is introduced in multiple stages during the reaction of plasma gas with the glass-ceramic composite LTCC ceramic substrate. The plasma gas consists of CF4 and Cl2. CF4 and Cl2 are introduced separately during the reaction. For example, CF4 is introduced in two stages, with the first stage lasting 5 minutes and the second stage lasting 15 minutes. Similarly, Cl2 is introduced in two stages: first, 100-150 sccm of Cl2 is introduced and the pressure is stabilized at 5 Pa; then, 150-200 sccm of Cl2 is introduced and the pressure is stabilized at 5 Pa.

[0060] In some embodiments, the reaction voltage is adjusted to 10V to 500V, such as 100V-150V or 300V; the reaction time includes 10min to 30min, such as 15min to 30min. The plasma gas reaction concentration is 10-200sccm, such as 10-100sccm, 50-100sccm, 100-150sccm, 150-200sccm, etc.

[0061] In some embodiments, the ceramic roughening method further includes: ultrasonic washing of the ceramic substrate surface with pure water or ultrasonic cleaning with acetone.

[0062] Specifically, after each reaction stage in the ceramic substrate reaction process, ultrasonic pure water washing or acetone ultrasonic cleaning is performed.

[0063] In conjunction with the above embodiments, the reaction of plasma gas with different LTCC ceramic substrates is described in detail below:

[0064] Example 1: Microcrystalline glass-based LTCC ceramic substrate

[0065] The interior of CaO-B2O3-SiO2 based LTCC ceramic substrates generally contains oxides such as CaO, SiO2, B2O3, Al2O3, and MgO. Through liquid-phase sintering, crystalline phases such as wollastonite, calcium borite, and quartz are generated in the glass phase, and a small amount of pores are also included.

[0066] Step 1: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to remove surface contaminants.

[0067] Step 2: Place the sample on the reaction platform and evacuate the equipment to 10°C. -3 Below Pa, 40 sccm CF4 is then introduced and the voltage is stabilized to 3 Pa. Then, an ignition voltage of about 50 V is applied, and the processing time is 5 min. During plasma etching, the opening pores on the surface of the ceramic substrate and the glass phase inside the substrate are preferentially etched. At this time, the ceramic surface forms a preliminary micro-etched state.

[0068] Step 3: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to clean the etched surface;

[0069] Step 3: Then, continue to pass 40 sccm CF4 and stabilize the voltage to 3 Pa. Input the start-up voltage, about 80 V, and process for 15 min. CBS-based microcrystalline glass is a polycrystalline ceramic. There are many defects at the grain boundaries between silicon dioxide crystals, wollastonite crystals, and calcium borite crystals, which are prone to grain boundary corrosion during plasma etching.

[0070] Step 4: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone for 15 minutes to clean the etched surface. At this time, the glass phase on the surface has been etched, and some grain boundaries have been etched to loosen the grains and form a micro-etched state.

[0071] Step 5: Subsequently, continue to introduce 40 sccm of CF4 and stabilize the voltage to 3 Pa. Apply an ignition voltage of approximately 100-150 V and process for 15 minutes. CF4 will ionize, forming various neutral groups or ions. 4- The mixture consists of CF3, CF2, CF, C, and F. Subsequently, F reacts with Si-O in the ceramic component, which has a lower bond energy, causing it to decompose and generate SiF gas, which is then removed by the vacuum system (see [link to documentation]). Figure 1 At this point, a low degree of roughening is formed on the substrate surface;

[0072] F + +SiO→SiF (1)

[0073] Step 6: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to clean the etched surface.

[0074] Step 7: Introduce 100 sccm CF4 and stabilize the voltage to 5 Pa. Then, apply an ignition voltage of about 300 V to allow F ions to continue reacting with the residual Si-O on the ceramic surface, achieving a state where the surface Si is completely removed.

[0075] Step 8: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone for 15 minutes to clean the etched surface; finally, the target silicon dioxide grains on the surface are etched, while the remaining grains are not etched, thereby achieving the purpose of roughening.

[0076] Example 2: Glass + Ceramic Composite LTCC Ceramic Substrate

[0077] Alumina-based LTCC ceramic substrates are made by adding a low-melting-point glass phase to alumina ceramics and sintering it. The glass is usually crystallized glass, and other crystalline phases and residual glass phases will precipitate during sintering.

[0078] Step 1: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to remove surface contaminants.

[0079] Step 2: Place the sample on the reaction platform, evacuate the equipment to below 10e-3Pa, then introduce 65sccmCF4 and stabilize the voltage to 3Pa, then input the ignition voltage of about 50V, and process for 5 minutes; In plasma etching, the opening pores on the surface of the ceramic substrate and the glass phase inside the substrate are preferentially etched; At this time, the ceramic surface forms a preliminary micro-etched state.

[0080] Step 3: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to clean the etched surface;

[0081] Step 4: Subsequently, continue to pass 80 sccm of CF4 and stabilize the voltage to 3 Pa. Apply an ignition voltage of approximately 80 V and process for 15 minutes. The Al2O3-based LTCC ceramic substrate is predominantly composed of alumina crystalline phase, with a small amount of other precipitated crystalline phases and residual glassy phases, classifying it as a multiphase composite ceramic. After the surface glassy phase is etched, the internal crystalline phases will begin to etch and loosen.

[0082] Step 5: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone for 15 minutes to clean the etched surface. At this time, the glass phase on the surface has been etched, and some grain boundaries have been etched to loosen the grains and form a micro-etched state.

[0083] Step 6: Close the CF4 intake, introduce 120 sccm of Cl2, and stabilize the voltage to 5 Pa. Then, apply an ignition voltage of approximately 100-150V to ionize the Cl2, forming various neutral groups or Cl... - Cl - The reaction continues with Al-O in the ceramic component, causing it to decompose and generate AlCl gas, which is then removed by the vacuum system. At this point, a low degree of roughening is formed on the substrate surface.

[0084] Cl + AlO → AlCl (2)

[0085] Step 7: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone ultrasonic cleaning for 15 minutes to clean the etched surface.

[0086] Step 8: Continue to introduce 180 sccm of Cl2 and stabilize the voltage to 5 Pa. Then, apply an ignition voltage of about 300 V to allow Cl2 to continue to react with Al-O in the ceramic components and decompose it to generate AlCl gas.

[0087] Step 9: Clean the surface of the ceramic substrate with ultrasonic pure water or acetone for 15 minutes to clean the etched surface; finally, the target alumina grains on the surface are etched, while the remaining grains are not etched, thereby achieving the purpose of roughening.

[0088] In summary, the specific process flow includes: pretreatment, cleaning oil stains and polishing fluid residue → placing the ceramic substrate into the main unit cavity and evacuating it → injecting carbon tetrafluoride → turning on the RF power supply of the equipment to start the ionization reaction and form a micro-etching state with the ceramic substrate → the main unit starts a special carbon tetrafluoride or chlorine gas program to automatically inject the gas into the cavity → the equipment is heated to the specified working temperature → the equipment turns on the RF power supply to start the ionization reaction, ionizing active plasma containing F and Cl to carry out the surface roughening reaction → completing the surface treatment of the ceramic substrate → the program ends and the substrate is removed from the equipment.

[0089] The surface reaction process of the ceramic substrate includes: gas → ionization into active particles → diffusion and adsorption onto the surface to be roughened → surface diffusion → reaction with the surface film → product desorption → leaving the ceramic substrate surface and exiting the chamber.

[0090] The embodiments in this specification utilize carbon tetrafluoride and chlorine as plasma reaction gases to achieve a significant surface roughening effect on ceramic substrates. Combined with the design of a pressure-reducing valve, it offers high safety and operability compared to existing technologies using hydrogen fluoride or sulfuric acid. Specifically, the substrate with initial roughness is placed in the main chamber of the plasma equipment, the flow rate of injected carbon tetrafluoride is 10-100 sccm, the treatment time is 5-30 minutes, and the pressure is stabilized at 3 Pa.

[0091] In conjunction with the above embodiments, the plasma equipment for ceramic roughening is connected to a storage container for storing plasma gas. A pressure reducing valve is installed between the plasma equipment and the storage container to regulate the concentration of plasma gas input from the storage container to the plasma equipment. During application, a suitable high-pressure cylinder is used as the storage container, and a suitable pressure reducing valve is used to regulate the gas concentration input to the plasma equipment. This convenient and safe method of introducing the reaction gas offers high safety and operability.

[0092] In this specification, similar or identical parts among the various embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the product embodiments described later are relatively simple in description since they correspond to the methods, and relevant parts can be referred to the descriptions in the system embodiments.

[0093] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for roughening ceramics, characterized in that, The process for manufacturing LTCC ceramic substrates for semiconductor testing, wherein the ceramic substrate is a microcrystalline glass system or a glass + ceramic composite system, the microcrystalline glass system is an aluminosilicate system or a borosilicate system, and the glass + ceramic composite system is an alumina-based system, the ceramic roughening method includes: Plasma gas is configured according to the ceramic properties, and the plasma gas is filled into the ceramic substrate with initial roughness. By adjusting the process parameters, the active plasma ionized by the plasma gas through high-frequency glow discharge reacts with the target components in the ceramic substrate with the initial roughness. The reaction rate of the active plasma with different oxide components in the ceramic substrate is different, resulting in a ceramic substrate with the target roughness; wherein the target roughness is greater than the initial roughness. Adjusting the process sequence of each component of the plasma gas, including introducing fluorine-containing gas and chlorine-containing gas separately into the plasma equipment, with fluorine-containing gas introduced before chlorine-containing gas; The ceramic substrate includes a crystalline phase, a glassy phase, and several pores. The active plasma reacts with the pores, glassy phase, and crystalline phase of the ceramic substrate at different rates and with different reactant phases.

2. The ceramic roughening method according to claim 1, characterized in that, Different ceramics are configured with different plasma gases, including: carbon tetrafluoride, sulfur hexafluoride, octafluoropropane, chloroform, tetrachlorosilane, boron trichloride, carbon tetrachloride, and chlorine.

3. The ceramic roughening method according to claim 1, characterized in that, The ceramic roughening method further includes: Adjust the number of times each component in the plasma gas is introduced.

4. The ceramic roughening method according to claim 3, characterized in that, Adjusting process parameters includes at least one of the following: Adjusting the concentration of plasma gas; Adjusting the pressure of the plasma gas; Adjust the reaction voltage; Adjust the reaction time.

5. The ceramic roughening method according to claim 3, characterized in that, The process sequence for adjusting the components of the plasma gas includes introducing carbon tetrafluoride and chlorine into the plasma equipment separately, with carbon tetrafluoride introduced before chlorine.

6. The ceramic roughening method according to claim 5, characterized in that, The reaction voltage is adjusted to 10V~500V; the reaction time is 10~30min; and the concentration of the plasma gas is 10-200 sccm.

7. The ceramic roughening method according to any one of claims 1-6, characterized in that, The ceramic roughening method further includes: The surface of the ceramic substrate is cleaned with ultrasonic pure water or acetone ultrasonic cleaning.

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