TGV substrate with high flatness and preparation method thereof

Abstract

The invention discloses a high-flatness TGV substrate and a preparation method thereof, and belongs to the technical field of TGV substrate manufacturing, and the preparation method comprises the following steps: firstly, depositing a passivation layer on each of the two surfaces of a glass substrate, coating one surface with a photosensitive dry film, and then performing laser irradiation and etching to form a TGV through hole; and then pasting a protective film or temporarily bonding a carrier plate on one surface which is not covered with the negative photosensitive dry film, filling conductive Cu slurry in the TGV through hole, curing and forming the Cu slurry, removing the photosensitive dry film, and polishing to obtain the TGV substrate. The passivation layers are deposited on the two faces of the glass substrate, pits are prevented from being formed in the polishing process, the etching face is covered with the negative photosensitive dry film, protection is provided for the etching process, the Cu columns in the through holes can be exposed to a certain height after the passivation layers are removed, polishing and grinding are further facilitated, the flatness of the substrate is further improved, and the yield of the substrate is improved. The surface roughness is reduced, the subsequent micromachining and packaging are facilitated, and the TGV substrate with higher flatness is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of TGV substrate manufacturing, and in particular to a TGV substrate with high flatness and a preparation method thereof. Background Art

[0002] With the rise of products in the fields of smart phones, the Internet of Things, automotive electronics, high-performance computing, 5G and artificial intelligence, advanced electronic packaging has gradually become an important means to achieve the miniaturization, lightness and multifunctionality of electronic products, and has also put forward higher requirements for advanced packaging. Through-silicon via (TSV) interposer technology has developed rapidly in recent years, but silicon material is a semiconductor material with a large loss tangent value. The conductor loss and dielectric loss of the substrate seriously affect the integrity of the signal. On the other hand, the processing and micro-assembly costs of silicon-based interposers are high, which seriously limits their application and development. Glass has become an attractive interposer material due to its adjustable thermal expansion coefficient (CTE), excellent surface flatness, high resistivity and low cost, providing another option for advanced manufacturing and packaging. Through-glass via (TGV) interposer technology is becoming a research hotspot for semiconductor companies and research institutes at home and abroad.

[0003] The commonly used TGV substrate is to use laser induction to denature the glass where it is irradiated by the laser, form a through hole after HF etching, and then use conductive copper paste to plug the hole, and finally complete it through the scraping and polishing process. However, due to the influence of impurity ions in the glass substrate, pits will appear after HF etching and polishing, and pits will also appear in the Cu at the plug hole, which will eventually affect the effect of subsequent metal wiring.

[0004] Based on the above content, a TGV substrate with high flatness and a preparation method thereof are proposed. Summary of the invention

[0005] The object of the present invention is to provide a TGV substrate with high flatness and a preparation method thereof, so as to solve the problems in the background technology.

[0006] To achieve the above object, the present invention provides a method for preparing a TGV substrate with high flatness, comprising the following steps:

[0007] S1, depositing a passivation layer on both sides of the glass substrate, and then covering one of the passivation layers with a negative photosensitive dry film;

[0008] S2, using laser to irradiate the side of the glass substrate covered with the negative photosensitive dry film, so that the photosensitive dry film at the corresponding position is ashed and the glass substrate is denatured;

[0009] S3, etching the glass substrate after laser irradiation induction to form a TGV through hole;

[0010] S4, attaching a protective film or a temporary bonding carrier to the side of the glass substrate that is not covered with the negative photosensitive dry film;

[0011] S5, filling the TGV through hole with conductive Cu paste to completely fill the entire TGV through hole;

[0012] S6. After the Cu paste is solidified and formed, the negative photosensitive dry film on the surface of the glass substrate is removed. At this time, the Cu column in the TGV through hole is highlighted, and the passivation layer on the entire surface is also exposed. Then, the glass substrate is polished, and the protective film or temporary bonding carrier on the other side is removed to obtain a TGV substrate with high flatness.

[0013] Preferably, in S1, the thickness of the passivation layer is 1 to 3 μm, and the passivation layer is SiO x 、SiN x , SiON or SiO x / SiN x In one of the stacking methods, the passivation layer is deposited by chemical vapor deposition or magnetron sputtering.

[0014] Preferably, in S1, the negative photosensitive dry film is coated on the passivation layer by vacuum lamination or roller lamination, and the thickness of the negative photosensitive dry film is 15-25 μm.

[0015] Preferably, in S6, the negative photosensitive dry film is removed by immersing in an alkaline solution.

[0016] Preferably, in S6, the polishing method is CMP polishing and grinding.

[0017] A TGV substrate with high flatness is prepared by the above preparation method.

[0018] Preferably, the interior of the TGV substrate is a glass substrate, both sides of the peeling substrate are passivation layers, and a plurality of Cu columns are embedded in the glass substrate.

[0019] Therefore, the TGV substrate with high flatness and the preparation method thereof of the present invention have the following beneficial effects:

[0020] (1) In the present invention, the passivation layer is deposited on both sides of the glass first, thereby isolating impurities from the glass substrate. In the subsequent processing, the passivation layer can be used as a polishing stop layer for the Cu column in the TGV plug hole to protect the glass substrate from being corroded by the etching solution, effectively avoiding the surface pit problem caused by over-polishing, and also providing a uniform surface for subsequent processes. The passivation layer has high insulation properties and can be left on the glass substrate without any influence on the subsequent processes and conductive properties.

[0021] (2) In the present invention, a negative photosensitive dry film is coated on one side of the passivation layer, which serves as a protective film for the passivation layer. It can be ashed by laser irradiation and effectively protect the underlying passivation layer. During the irradiation process, the laser irradiation area can be precisely controlled to ensure that only the part that needs to be etched is processed, and the ashed photosensitive dry film can be used as an etching mask to simplify the subsequent etching process. Finally, when removing, the Cu column in the through hole can be exposed to a certain height, which is conducive to further polishing and flattening.

[0022] (3) In the present invention, a protective film or a temporary bonding carrier is provided on the side not covered with the dry film, which can prevent the back side from being damaged during the etching process, ensure the integrity of the entire substrate, and also provide additional mechanical support to facilitate subsequent processing steps.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a glass substrate after being processed in step 1 in an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of a glass substrate after being processed in step 2 in an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of a glass substrate after being processed in step 3 in an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of a glass substrate after being processed in step 4 in an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of a glass substrate after being processed in step 5 in an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of a glass substrate after being processed in step 6 in an embodiment of the present invention Figure 1 ;

[0030] Figure 7 A schematic diagram of a TGV substrate obtained in an embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of a TGV substrate obtained in a comparative example of the present invention;

[0032] Reference numerals:

[0033] 1. Glass substrate; 2. Passivation layer; 3. Photosensitive dry film; 4. TGV through hole; 5. Protective film or temporary bonding carrier; 6. Cu column. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0036] Example

[0037] In this embodiment, a TGV substrate with high flatness is prepared by the following method:

[0038] S1. Use PECVD or PVD equipment to preferentially deposit a 3 μm thick SiOx / SiNx stack (passivation layer 2) on both sides of the glass substrate 1, and then use vacuum bonding to cover the A side of the glass substrate 1 with a 20 μm thick negative photosensitive dry film 3, such as Figure 1 As shown;

[0039] S2. According to the preset coordinate points, a laser is used to irradiate the side of the glass substrate 1 covered with the negative photosensitive dry film 3. The part of the photosensitive dry film 3 irradiated by the high-energy laser is ashed. At the same time, the glass substrate 1 below is denatured due to the high-energy laser irradiation. Figure 1 As shown;

[0040] S3, etching the glass substrate 1 after laser irradiation to form a TGV through hole 4. Since the glass surface is protected by the passivation layer 2, the etching liquid can be prevented from corroding the glass, effectively preventing the problem of pits on the glass surface. Figure 3 As shown;

[0041] S4, affix a protective film or a temporary bonding carrier 5 to the side of the glass substrate 1 that is not covered with the negative photosensitive dry film 3, such as Figure 4 As shown;

[0042] S5, fill the TGV through hole 4 with conductive Cu paste, and solidify it to completely fill the entire TGV through hole 4, such as Figure 5 As shown;

[0043] S6. After the Cu slurry is solidified and formed, the negative photosensitive dry film 3 on the surface of the glass substrate 1 is removed by soaking in a KOH solution. At this time, the Cu column 6 in the TGV through hole 4 is highlighted, and the entire passivation layer 2 is also exposed. Then, the glass substrate 1 is subjected to CMP polishing and grinding to remove the protective film or temporary bonding carrier 5 on the other side. Since the hardness of the added passivation layer 2 is much greater than the hardness of Cu, the passivation layer 2 can act as a polishing stop layer during the polishing process, thereby avoiding the surface pit phenomenon caused by over-polishing, and obtaining a TGV substrate with high flatness, such as Figure 6 , 7 shown.

[0044] Comparative Example

[0045] The TGV substrate is manufactured using the traditional method as follows:

[0046] The glass substrate 1 is irradiated with laser at a preset point, and the glass substrate 1 induced by laser irradiation is etched to form a TGV through hole 4, and a conductive Cu paste is directly filled in the through hole, and solidified to completely fill the entire TGV through hole 4; the Cu paste is solidified to form a Cu column 6, and then the glass substrate 1 is polished by CMP to obtain a TGV substrate, such as Figure 8 shown.

[0047] The TGV substrates obtained in the embodiment and the comparative example were tested respectively. Both sides of the TGV substrate obtained in the embodiment were flat without pits, while one side of the TGV substrate obtained in the comparative example had a depression with a depth of 8 μm. It can be concluded that the TGV substrate prepared by the method of the present invention has no pits and a flat surface, which will not affect the subsequent metal wiring effect.

[0048] Therefore, the present invention provides a TGV substrate with high flatness and a preparation method thereof. By depositing a passivation layer on both sides of a glass substrate, pits are avoided from being formed during the polishing process. A negative photosensitive dry film is covered on the etched surface to provide protection for the etching process. After removal, the Cu column in the through hole can be exposed to a certain height, which is conducive to further polishing and flattening, further improving the flatness of the substrate, reducing the surface roughness, facilitating subsequent micro-machining and packaging, and forming a TGV substrate with high flatness.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a TGV substrate with high flatness, characterized in that: The following steps are involved: S1, depositing a passivation layer on both sides of the glass substrate, and then covering one of the passivation layers with a negative photosensitive dry film; S2, using laser to irradiate the side of the glass substrate covered with the negative photosensitive dry film, so that the photosensitive dry film at the corresponding position is ashed and the glass substrate is denatured; S3, etching the glass substrate after laser irradiation induction to form a TGV through hole; S4, attaching a protective film or a temporary bonding carrier to the side of the glass substrate that is not covered with the negative photosensitive dry film; S5, filling the TGV through hole with conductive Cu paste to completely fill the entire TGV through hole; S6. After the Cu paste is solidified and formed, the negative photosensitive dry film on the surface of the glass substrate is removed. At this time, the Cu column in the TGV through hole is highlighted, and the entire passivation layer is also exposed. Then the glass substrate is polished, and the protective film or temporary bonding carrier is removed to obtain a TGV substrate with high flatness.

2. The method for preparing a TGV substrate with high flatness according to claim 1, characterized in that: In S1, the thickness of the passivation layer is 1 to 3 μm, and the passivation layer is SiO x 、SiN x , SiON or SiO x / SiN x In one of the stacking methods, the passivation layer is deposited by chemical vapor deposition or magnetron sputtering.

3. The method for preparing a TGV substrate with high flatness according to claim 1, characterized in that: In the above S1, the negative photosensitive dry film is coated on the passivation layer by vacuum lamination or roller lamination, and the thickness of the negative photosensitive dry film is 15-25 μm.

4. The method for preparing a TGV substrate with high flatness according to claim 1, characterized in that: In S6, the negative photosensitive dry film is removed by immersing it in an alkaline solution.

5. The method for preparing a TGV substrate with high flatness according to claim 1, characterized in that: In S6, the polishing method is CMP polishing and grinding.

6. A TGV substrate with high flatness, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 5.

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