TGV substrate structure

Abstract

The invention relates to the technical field of TGV substrates, in particular to a TGV substrate structure which comprises a TGV substrate, a plurality of glass through holes are formed in the TGV substrate, and filling copper for interconnection of multiple layers of TGV substrates is arranged in each glass through hole; the blind holes are arranged around each glass through hole and are used for buffering thermal expansion of the filling copper; and the filling film is arranged in the blind hole and is matched with the blind hole to buffer the thermal expansion of the filling copper. The blind hole is formed around the glass through hole, the filling film is arranged in the blind hole, and the hole structure and the filling film are utilized to buffer deformation of the TGV substrate under the condition that the filling copper is heated and expanded, so that the possibility that the TGV substrate cracks and even chippings are generated due to the fact that the heating expansion amount of the filling copper is larger than the expansion amount of the TGV substrate is reduced, the safety of the TGV substrate is guaranteed, and the production efficiency of the TGV substrate is improved. And therefore, the safety and the use stability of the TGV packaging chip can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of TGV substrates, and in particular to a TGV substrate structure. Background Art

[0002] The key to the development and integration of chiplet heterogeneous integration technology lies in the integration of multi-scale and multi-dimensional chip interconnection, thereby improving power efficiency and reducing latency, providing smaller and higher-performance chips for high-performance computing, artificial intelligence, and smart terminals.

[0003] The vertical interconnection of chips relies on technologies such as through silicon via (TSV) or through glass via (TGV), while the horizontal interconnection is achieved through redistribution layer (RDL) technology.

[0004] TGV through-hole filling material is typically copper (Cu), which has a significantly different thermal expansion coefficient from the glass substrate material: 17ppm / °C, compared to 3-5ppm / °C for TGV glass. After metal filling of the TGV glass through-hole, if the TGV substrate operates in a high-temperature environment, the Cu rapidly expands, squeezing the glass material on the through-hole sidewalls. This can easily crack the glass substrate, leading to the risk of failure in TGV advanced packaged chip products. Summary of the Invention

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A TGV substrate structure includes a TGV substrate, wherein a plurality of glass through holes are formed on the TGV substrate, and each glass through hole is provided with a filling copper for interconnecting multiple layers of TGV substrates;

[0007] and blind holes arranged around each through-glass hole for buffering the thermal expansion of the filled copper;

[0008] and a filling film which is arranged in the blind hole and cooperates with the blind hole to buffer the thermal expansion of the filled copper.

[0009] Furthermore, the blind vias include blind via 1 and blind via 2, disposed on both sides of the TGV substrate. The vertical positions of blind via 1 and blind via 2 are staggered. This staggered arrangement prevents accidental penetration of the upper and lower blind vias during drilling, which could reduce the physical volume of the TGV substrate around the through-glass via and thus affect the strength of the copper-filled support structure. When the number of blind vias 1 and 2 is appropriately reduced, the staggered arrangement of blind vias 1 and 2 can also be a planar staggered arrangement. For example, a blind via 1 has a center angle of 0°, an adjacent blind via 1 has a center angle of 45°, and an opposing blind via 2, located between the two blind vias, has a center angle of 22.5°. The center angles of the adjacent blind vias 2 are then 45° + 22.5° = 67.5°. This staggered arrangement also provides a similar buffering effect.

[0010] Furthermore, the blind hole depth is 40%-60% of the TGV substrate thickness. Considering the structural strength of the TGV substrate to maintain the copper filling position, the depth should not be set too deep, generally half the TGV substrate thickness. The specific depth can be adaptively adjusted according to specific circumstances.

[0011] Furthermore, the diameter of the blind hole is 10%-50% of the diameter of the through-glass hole. If the blind hole is set too large, it will occupy more surface space of the TGV substrate, while if it is set too small, the number of blind holes needs to be increased to compensate. In addition, the blind hole with a diameter that is too small is not easy to process.

[0012] Furthermore, the filler film is an organic film with a low Young's modulus, including but not limited to polyimide, parylene, and soluble polytetrafluoroethylene. Polyimide, parylene, and soluble polytetrafluoroethylene all have good heat resistance, ranging from 200°C to 300°C, while the operating temperature of the TGV substrate is generally not within this temperature range.

[0013] Furthermore, the Young's modulus of the organic film material is less than 3 GPa. The lower the Young's modulus, the easier the material is to deform. Conversely, the higher the Young's modulus, the more difficult the material is to deform. The filling film needs to provide a buffering effect, so it is necessary to select a material that is easily deformable.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. The present invention provides a blind hole around the through-glass hole and disposes a filling film within the blind hole. The hole structure and the filling film cushion the deformation of the TGV substrate caused by the thermal expansion of the filling copper. This reduces the possibility of cracks or even chipping in the TGV substrate caused by the thermal expansion of the filling copper exceeding the TGV substrate, thereby ensuring the safety of the TGV substrate and, in turn, the safety and stable use of the TGV packaged chip.

[0016] 2. The staggered arrangement of blind via 1 and blind via 2 in the present invention, combined with the limitation of depth and diameter, provides a buffering effect while maintaining the structural strength of the TGV substrate around the copper filling.

[0017] 3. In the present invention, blind hole 1 and blind hole 2 are vertically staggered. When multiple through-glass holes are close to each other, blind hole 1 and blind hole 2 can both be used as blind holes for adjacent through-glass holes, thereby reducing the actual number of holes opened and the processing workload.

[0018] 4. In the present invention, the blind holes and the filling film are both located on the inner side of the TGV substrate and do not form protrusions on the surface of the TGV substrate. Therefore, when in use, the filling film does not affect the normal use of the TGV substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the arrangement of the through-glass hole in the present invention;

[0020] Figure 2 Schematic diagram of the arrangement of blind holes in the present invention;

[0021] Figure 3 It is a schematic diagram of the arrangement of copper filling in the present invention;

[0022] Figure 4 It is a schematic diagram of the setting of the filling membrane in the present invention.

[0023] Reference numerals: 1, TGV substrate; 2, through-glass via; 3, blind via 1; 4, blind via 2; 5, filled copper; 6, filled film. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] The present application provides a TGV substrate structure, which mainly solves the problem that the current TGV substrate has a large difference in thermal expansion coefficient between the copper material used to fill the TGV through hole and the TGV substrate material. The copper expansion at high temperature easily causes the TGV substrate to crack or even break. The following technical solutions are provided. Figures 1-4 Give detailed instructions:

[0026] A TGV substrate structure includes a TGV substrate 1 having a thickness of 0.3 mm to 2 mm. The TGV substrate 1 is provided with through-glass holes 2, which are also referred to as TGVs in the industry. The number and position of the through-glass holes 2 vary depending on the design of the TGV substrate 1. Blind holes are provided on the TGV substrate 1 at equal intervals outside each through-glass hole 2.

[0027] The blind vias include blind via 1 3 and blind via 2 4, which are located on the upper and lower surfaces of the TGV substrate 1. The blind via depth is 40%-60% of the thickness of the TGV substrate 1. In this embodiment, the blind via depth is 50% of the thickness of the TGV substrate 1. The blind via diameter is 10%-50% of the diameter of the through-glass via 2. In this embodiment, the blind via diameter is 30% of the diameter of the through-glass via 2. The vertical positions of blind via 1 3 and blind via 2 4 are staggered.

[0028] A copper filler 5 is installed in the through-glass via 2. When in use, the multi-layer TGV substrates 1 are electrically connected at the location of the copper filler 5, forming an interconnection between the multi-layer substrates. A filler film 6 is installed in both the blind via 1 3 and the blind via 2 4. The filler film 6 is made of an organic film material with a low Young's modulus, such as polyimide, parylene, and soluble polytetrafluoroethylene. The Young's modulus of the organic film material is less than 3GPa.

[0029] The production method of the TGV substrate comprises the following steps:

[0030] S1: Provide a TGV glass substrate, set a preset position of a through-glass hole 2, and use laser induction or laser induction + acid-base etching to make blind holes on both sides of the TGV substrate 1 outside the through-glass hole 2 according to the preset position of the through-glass hole 2, with the positions of the blind holes on both sides staggered;

[0031] S2: Filling the blind hole with an organic film material having a low Young's modulus to fill the blind hole completely, wherein the Young's modulus of the organic film material is less than 3 GPa;

[0032] S3: using laser induction or laser induction + acid-base etching to open the through-glass hole 2 at the preset position of the through-glass hole 2;

[0033] S4: filling the through-glass hole 2 with Cu metal. First, a metal seed layer is deposited on the inner wall of the through-glass hole 2 by magnetron sputtering, and then Cu metal is deposited by electroplating until the through-glass hole 2 is completely filled.

[0034] In S1 and S3, laser induced processing can be performed by UV laser drilling, picosecond / femtosecond laser drilling, and CO2 laser drilling.

[0035] By providing blind vias around the through-glass via 2 on the TGV substrate 1, when used in a high-temperature environment, when the filled copper 5 expands due to heat, and the expansion amplitude is greater than the expansion amplitude of the TGV substrate 1, the first blind via 3 and the second blind via 4 can act as a buffer for the deformation of the surrounding TGV substrate 1 after the expansion of the filled copper 5, reducing the extrusion strength on the surrounding TGV substrate 1, thereby reducing the possibility of cracks or even breakage of the TGV substrate 1;

[0036] At the same time, the blind hole is filled with a filling film 6, and the filling film 6 is made of an organic film material with a low Young's modulus. The lower the Young's modulus, the easier the material is to deform. When the filled copper 5 expands and squeezes the TGV substrate 1 outward, the blind hole uses its own pore structure to buffer the pressure, while the filling film 6 can also absorb and buffer the squeezing force. The two are used in conjunction with each other to enhance the buffering effect of the expansion of the filled copper 5. In addition, the filling film 6 is located in the blind hole 1 3 and the blind hole 2 4 to fill the blind hole. When the blind hole buffers the expansion of the filled copper 5 and causes itself to deform, the filling film 6 can reduce the probability of cracks in the blind hole itself caused by deformation, thereby providing a better crack prevention effect for the entire TGV substrate 1.

[0037] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A TGV substrate structure, comprising a TGV substrate (1), characterized in that: The TGV substrate (1) is provided with a plurality of through-glass holes (2), each of which is provided with a filling copper (5) for interconnecting multiple layers of the TGV substrate (1); and blind holes arranged around each through-glass hole (2) for buffering the thermal expansion of the filled copper (5); and a filling film (6) arranged in the blind hole and cooperating with the blind hole to buffer the thermal expansion of the filled copper (5).

2. The TGV substrate structure according to claim 1, characterized in that: The blind holes include a blind hole 1 (3) and a blind hole 2 (4) arranged on both sides of the TGV substrate (1), and the vertical positions of the blind hole 1 (3) and the blind hole 2 (4) are staggered with each other.

3. The TGV substrate structure according to claim 2, characterized in that: The depth of the blind hole is 40%-60% of the thickness of the TGV substrate (1).

4. The TGV substrate structure according to claim 3, characterized in that: The diameter of the blind hole is 10%-50% of the diameter of the glass through hole (2).

5. The TGV substrate structure according to claim 1, characterized in that: The filling film (6) is an organic film with low Young's modulus, including but not limited to polyimide, parylene and soluble polytetrafluoroethylene.

6. The TGV substrate structure according to claim 5, characterized in that: The Young's modulus of the organic film material is less than 3 GPa.

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