Ceramic substrate processing method capable of being used for advanced packaging
Through a ceramic substrate processing method including sintering, cutting, chamfering, grinding, polishing and chemical mechanical polishing, the limitations of the existing intermediate layer materials in terms of thermal conductivity, electrical insulation and mechanical properties are solved, and the processing of a aluminum nitride substrate with high precision and excellent performance is achieved.
Patent Information
- Application Number
- CN202510157367.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-05-13
AI Technical Summary
The existing intermediate layer materials have limitations in thermal conductivity, electrical insulation and mechanical properties, and are difficult to meet the needs of high-power and high-frequency devices. In addition, aluminum nitride ceramics have problems with surface morphology and roughness in the manufacturing of high-precision intermediate layers.
A ceramic substrate processing method is provided, including sintering, cutting, chamfering, double-sided grinding, double-sided polishing and chemical mechanical polishing, etc., through these steps, the aluminum nitride ceramic is processed to improve its mechanical strength, insulation and thermal conductivity.
The processed aluminum nitride substrate has excellent surface morphology, mechanical strength, insulation and thermal conductivity, meets the needs of high-precision intermediate layers and is suitable for advanced packaging.
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Figure CN119993840A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a ceramic substrate processing method that can be used for advanced packaging. Background Art
[0002] As the performance and integration of electronic devices continue to improve, the role of advanced packaging in the semiconductor industry is becoming increasingly important. As a key structure in advanced packaging, the interposer can achieve high-density signal interconnection, efficient thermal management and multi-chip integration, and plays an important role in the fields of 3D IC, heterogeneous integration and power electronics.
[0003] However, the materials of the interposer are mainly silicon (Si) and glass (SiO2), which have certain limitations in thermal conductivity, electrical insulation and mechanical properties, and are difficult to meet the needs of high-power and high-frequency devices.
[0004] Heat dissipation is one of the problems that need to be solved urgently in advanced packaging. Aluminum nitride ceramics have high thermal conductivity, low expansion coefficient, high dielectric constant, high mechanical strength, excellent electrical insulation and mechanical properties, and are considered to be ideal materials for advanced packaging, which is very consistent with the performance requirements of intermediate layer substrates for advanced packaging. However, due to the polycrystalline characteristics of aluminum nitride materials themselves and the limitations of traditional preparation processes, the surface morphology and surface roughness are still difficult to meet the high-precision requirements of wafer manufacturing. There are still many problems in the manufacture of high-precision intermediate layers suitable for semiconductor processes. Summary of the invention
[0005] The purpose of the present invention is to provide a ceramic substrate processing method that can be used for advanced packaging in order to solve the above-mentioned technical problems, thereby achieving the effects of high thermal conductivity, high insulation and mechanical strength.
[0006] In view of this, the present invention provides a method for processing a ceramic substrate that can be used for advanced packaging, comprising the following steps:
[0007] S1: Sintering, mixing aluminum nitride powder and additives to form granules, and then sintering at high temperature to form aluminum nitride ceramics after compression molding;
[0008] S2: cutting, cutting the aluminum nitride ceramic into thin slices;
[0009] S3: chamfering, chamfering the cut slices;
[0010] S4: Double-sided grinding, double-sided grinding of the chamfered slice to improve the parallelism of the aluminum nitride substrate and preliminarily control the surface roughness;
[0011] S5: Double-sided polishing, performing double-sided polishing on the double-sided ground wafer to control the dimensional accuracy of the aluminum nitride substrate and improve the flatness;
[0012] S6: Chemical mechanical polishing, chemical mechanical polishing is performed on the double-sided polished wafer.
[0013] In the present technical solution, the aluminum nitride substrate processed by this method has mechanical strength, bending strength higher than 300MPa, and compressive strength higher than 2400MPa. The aluminum nitride substrate has insulation, volume resistivity higher than 1014Ω·cm, dielectric strength higher than 20KV / mm, and insulation thermal conductivity should be higher than 170W / (m·K).
[0014] Furthermore, the particle size of the aluminum nitride powder in S1 is 0.01-50 microns.
[0015] Furthermore, in S1, mechanical force or hydraulic pressure is used for compression molding, and the strength of the mechanical force or hydraulic pressure is 1MPa-300MPa.
[0016] Furthermore, the aluminum nitride ceramics after sintering in S1 are in the form of regular cylinders or cubes.
[0017] Furthermore, the cutting method of the aluminum nitride ceramic in S2 is peripheral cutting, inner peripheral cutting or multi-wire cutting.
[0018] Furthermore, the thickness of the slice cut out in S2 is less than 1 mm.
[0019] Furthermore, in S3, the chamfer shape is semicircular, trapezoidal or elliptical.
[0020] Furthermore, the abrasive grains or powders used in the double-sided grinding in S4 are one or a mixture of aluminum oxide, boron nitride, silicon carbide, polycrystalline diamond, and single crystal diamond;
[0021] Furthermore, the abrasive grains or micro powder used for double-sided polishing in S5 are one or a mixture of aluminum oxide, silicon carbide, boron nitride, polycrystalline diamond, and single crystal diamond;
[0022] Furthermore, the abrasive grains or micro powders used in chemical mechanical polishing in S6 are silicon oxide, cerium oxide, or a mixture of several thereof;
[0023] Furthermore, the concentration of the abrasive particles or micro powder is 0-40wt%.
[0024] Furthermore, the particle size of the abrasive grains or micro powder is 0.05-10 microns.
[0025] In the present technical solution, the processed aluminum nitride substrate has excellent surface morphology, mechanical strength, insulation and thermal conductivity, a total thickness variation (TTV) of less than 20 microns, a warp (Warp) of less than 80 microns, a bow (Bow) of less than 40 microns, a surface roughness Sa of less than 10 nanometers, a size of 2-40 inch round or square piece, and a thickness of less than 1 mm.
[0026] The beneficial effects of the present invention are:
[0027] 1. It can improve the basic surface morphology and surface roughness of aluminum nitride, effectively meet the requirements of the intermediate layer in terms of high thermal conductivity, high insulation, mechanical strength and high precision, and help improve the performance and industrial development of semiconductor devices.
[0028] 2. The aluminum nitride substrate processed by this method has mechanical strength, bending strength higher than 300MPa, compressive strength higher than 2400MPa, insulation, volume resistivity higher than 1014Ω·cm, dielectric strength higher than 20KV / mm, and insulation thermal conductivity higher than 170W / (m·K).
[0029] 3. The processed aluminum nitride substrate has excellent surface morphology, mechanical strength, insulation and thermal conductivity, with a total thickness variation (TTV) of less than 20 microns, a warp (Warp) of less than 80 microns, a bow (Bow) of less than 40 microns, a surface roughness Sa of less than 10 nanometers, a size of 2-40 inch round or square pieces, and a thickness of less than 1 mm. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 is a schematic diagram of a process flow according to an embodiment of the present disclosure;
[0031] Figure 2 is a microscopic observation diagram of an ESM according to a first embodiment of the present disclosure;
[0032] Figure 3 is a microscopic observation diagram of an ESM according to a second embodiment of the present disclosure;
[0033] Figure 4 is a surface observation diagram of a sample 1 according to a first embodiment of the present disclosure using a white light interference microscope;
[0034] Figure 5 is a surface observation diagram of sample 2 using a white light interference microscope according to one embodiment 1 of the present disclosure;
[0035] Figure 6 is a surface TTV observation diagram of the optical profilometer of the sample 1 according to the embodiment 1 of the present disclosure;
[0036] Figure 7 It is a diagram of the surface warpage observation of the optical profiler of the sample 1 according to the embodiment 1 of the present disclosure. DETAILED DESCRIPTION
[0037] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.
[0038] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.
[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.
[0040] It should be noted that, in the description of the present application, the orientation or positional relationship indicated by terms such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise stated, these orientation words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application; the orientation words "inside and outside" refer to the inside and outside relative to the contour of each component itself.
[0041] It should be noted that, in the present application, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises one..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be noted that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.
[0042] like Figure 1-7 As shown, reference Figure 1 The process flow chart shows that first, aluminum nitride powder is mixed with an additive to form granules, and is molded by mechanical or hydraulic pressure, and isostatically pressed and sintered to form aluminum nitride ceramics; the aluminum nitride ceramics are sliced by peripheral cutting, internal peripheral cutting, multi-wire cutting and other methods to obtain aluminum nitride cutting sheet substrates; in order to reduce the occurrence of scratches in the subsequent process, the aluminum nitride substrate is chamfered by a chamfering device, and the chamfer shapes include semicircular, trapezoidal, elliptical, etc.; double-sided grinding equipment is used to improve the parallelism of the aluminum nitride substrate, improve the flatness, and preliminarily control the surface roughness; double-sided polishing is used to control the dimensional accuracy of the aluminum nitride substrate and further improve the flatness; chemical mechanical polishing is performed to ensure that the size, surface morphology, surface roughness, etc. of the aluminum nitride substrate meet the requirements of advanced packaging substrates.
[0043] The abrasive grains or micro-powder used in the double-sided grinding are one or a mixture of aluminum oxide, boron nitride, silicon carbide, polycrystalline diamond, and single crystal diamond; the abrasive grains or micro-powder used in the double-sided polishing are one or a mixture of aluminum oxide, silicon carbide, boron nitride, polycrystalline diamond, and single crystal diamond; the abrasive grains or micro-powder used in the chemical mechanical polishing (CMP) are one or a mixture of silicon oxide and cerium oxide; the particle size of the abrasive grains or micro-powder is 0.05-10 microns, and the concentration of the abrasive grains or micro-powder is 0-40wt%.
[0044] The aluminum nitride substrate has excellent surface morphology, mechanical strength, insulation and thermal conductivity.
[0045] Preferably, the surface morphology of the aluminum nitride substrate is: the total thickness variation (TTV) is less than 20 microns, the warp (Warp) is less than 80 microns, the bow (Bow) is less than 40 microns, the surface roughness Sa is less than 10 nanometers, the size is a 2-40 inch round or square piece, and the thickness is less than 1 mm;
[0046] The mechanical strength of the aluminum nitride substrate: the bending strength should be higher than 300MPa, and the compressive strength should be higher than 2400MPa; the insulation of the aluminum nitride substrate: the volume resistivity should be higher than 1014Ω·cm, and the dielectric strength should be higher than 20KV / mm. The insulation thermal conductivity of the aluminum nitride substrate should be higher than 170W / (m·K).
[0047] Embodiment 1
[0048] Use aluminum nitride powder with a particle size of 5 microns such as Figure 2 As shown, it is mixed with 10wt% yttrium oxide auxiliary agent and granulated, and is compression molded at a pressure of 20MPa and sintered at an isostatic pressure of 150MPa. The sintering temperature is 1830°C and slowly cooled to room temperature to obtain aluminum nitride ceramics.
[0049] The aluminum nitride ceramics were sliced by multi-wire cutting to obtain a 6-inch circular substrate with a thickness of about 1 mm. The mechanical, electrical and thermal properties of the aluminum nitride substrate samples 1 and 2 are shown in the following table:
[0050] Bending strength Compressive strength Volume resistivity Dielectric strength Thermal conductivity Sample 1 304MPa 2500MPa 1014Ω·cm 20KV / mm 171 Sample 2 301MPa 2500MPa 1014Ω·cm 20KV / mm 173
[0051] The edge is chamfered using a chamfering device, and the chamfer is semicircular R = 0.5 mm.
[0052] The upper and lower surfaces of the aluminum nitride substrate were ground using a double-sided grinding device. The grinding liquid used was 20wt% diamond grinding liquid with a particle size of 10 microns. The grinding equipment speed was 50rpm / min, the grinding pressure was 120kpa, the removal amount was 100 microns, the surface parallelism and flatness were improved, and the surface roughness reached 500 nanometers.
[0053] The upper and lower surfaces of the aluminum nitride substrate were polished using a double-sided polishing device. The polishing liquid used was 20wt%, an aluminum oxide polishing liquid with a particle size of 3 microns. The polishing equipment speed was 30rpm / min, the grinding pressure was 100kpa, the removal amount was 20 microns, the surface flatness was improved, and the surface roughness reached 50 nanometers.
[0054] The single side of the aluminum nitride substrate was polished using chemical mechanical polishing equipment. The polishing liquid used was 20wt% silicon oxide polishing liquid with a particle size of 200 nanometers. The polishing equipment speed was 100rpm / min, the grinding pressure was 80kpa, the removal amount was 10 microns, the surface flatness was improved, and the surface roughness reached 4 nanometers.
[0055] Two groups of aluminum nitride substrate samples 1 and 2 were selected. After the above-mentioned grinding and polishing treatment, the surface morphology and surface roughness of the aluminum nitride substrates are shown in the following table:
[0056] Sa TTV Warp Bow Sample 1 4.12nm 2.38μm 36.2μm 16.1μm Sample 2 4.1nm 3.14μm 47.4μm 18.5μm
[0057] The surface roughness Sa of aluminum nitride substrate sample 1 and sample 2 after chemical mechanical polishing is as follows: Figure 4 and Figure 5 As shown, they are 4.12 nm and 4.1 nm respectively; Figure 6 The surface morphology of aluminum nitride substrate sample 1 was observed, and the TTV was 2.38 microns; Figure 7 The surface morphology of aluminum nitride substrate sample 1 was observed, and the Warp and Bow were 36.2 microns and 16.1 microns respectively.
[0058] Embodiment 2
[0059] Aluminum nitride micropowder with a particle size of 15 microns is mixed with 5wt% yttrium oxide and 1wt% calcium oxide as auxiliary agents to form granules, which are compression molded at a pressure of 30MPa and sintered at an isostatic pressure of 180MPa. The sintering temperature is 1820°C and slowly cooled to room temperature to obtain aluminum nitride ceramics.
[0060] The aluminum nitride ceramics were sliced by multi-wire cutting to obtain a 4-inch square substrate with a thickness of about 1 mm. The mechanical, electrical and thermal properties of aluminum nitride substrate samples 3 and 4 are shown in the following table:
[0061]
[0062] The edge was chamfered using a chamfering device, and the chamfer was semicircular R = 0.5 mm. The upper and lower surfaces of the aluminum nitride substrate were ground using a double-sided grinding device, and the grinding liquid used was 20wt%, diamond grinding liquid with a particle size of 6 microns, the grinding equipment speed was 30rpm / min, the grinding pressure was 100kpa, the removal amount was 100 microns, the surface parallelism and flatness were improved, and the surface roughness reached 500 nanometers.
[0063] The upper and lower surfaces of the aluminum nitride substrate were polished using a double-sided polishing device. The polishing liquid used was 20wt%, an aluminum oxide polishing liquid with a particle size of 3 microns. The polishing equipment speed was 25rpm / min, the grinding pressure was 80kpa, the removal amount was 25 microns, the surface flatness was improved, and the surface roughness reached 50 nanometers.
[0064] The single side of the aluminum nitride substrate was polished using chemical mechanical polishing equipment. The polishing liquid used was 20wt% silicon oxide polishing liquid with a particle size of 100 nanometers. The polishing equipment speed was 120rpm / min, the grinding pressure was 80kpa, the removal amount was 10 microns, the surface flatness was improved, and the surface roughness reached 4 nanometers.
[0065] Two groups of aluminum nitride substrate samples 3 and 4 were selected. After the above-mentioned grinding and polishing treatment, the surface morphology and surface roughness of the aluminum nitride substrates are shown in the following table:
[0066] Sa TTV Warp Bow Sample 3 4.5nm 2.12μm 26.2μm 14.7μm Sample 4 4.9nm 2.58μm 27.4μm 16.3μm
[0067] After chemical mechanical polishing, the surface roughness Sa of the aluminum nitride substrate samples 3 and 4 are 4.5 nanometers and 4.9 nanometers, respectively, the TTV is 2.12 microns and 2.58 microns, the Warp is 26.2 microns and 27.4 microns, and the Bow is 14.7 microns and 16.3 microns.
[0068] The embodiments of the present application are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A method for processing a ceramic substrate that can be used for advanced packaging, characterized in that , including the following steps: S1: Sintering, mixing aluminum nitride powder and additives to form granules, and then sintering at high temperature to form aluminum nitride ceramics after compression molding; S2: cutting, cutting the aluminum nitride ceramic into thin slices; S3: chamfering, chamfering the cut slices; S4: Double-sided grinding, double-sided grinding of the chamfered slice to improve the parallelism of the aluminum nitride substrate and preliminarily control the surface roughness; S5: Double-sided polishing, double-sided polishing of the double-sided ground wafer to control the dimensional accuracy of the aluminum nitride substrate and improve flatness; S6: Chemical mechanical polishing, chemical mechanical polishing is performed on the double-sided polished wafer.
2. A method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The particle size of the aluminum nitride powder in S1 is 0.01-50 microns.
3. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: In S1, mechanical force or hydraulic pressure is used for compression molding, and the strength of the mechanical force or hydraulic pressure is 1MPa-300MPa.
4. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The cutting method of aluminum nitride ceramics in S2 is peripheral cutting, inner peripheral cutting or multi-wire cutting.
5. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The thickness of the slices cut out in S2 is less than 1 mm.
6. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: In S3, the chamfer shape is semicircular, trapezoidal or elliptical.
7. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The abrasive grains or micro powder used for double-sided grinding in S4 are one or a mixture of aluminum oxide, boron nitride, silicon carbide, polycrystalline diamond, and single crystal diamond.
8. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The abrasive grains or micro powders used for double-sided polishing in S5 are one or a mixture of aluminum oxide, silicon carbide, boron nitride, polycrystalline diamond, and single crystal diamond.
9. The method for processing a ceramic substrate for advanced packaging according to claim 1, characterized in that: The abrasive grains or micro powders used in chemical mechanical polishing in S6 are silicon oxide, cerium oxide or a mixture of several thereof.
10. The method for processing a ceramic substrate for advanced packaging according to claim 7, characterized in that: The concentration of abrasive particles or micro powder is 0-40wt%.