JP2013038165A - Joining substrate with through wiring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining substrate with through wiring which prevents an electrode from being damaged due to thermal expansion of a resin disposed in a through hole.SOLUTION: A joining substrate with through wiring 10A includes: a first substrate 1 where an electrode layer 2 is formed on one surface 1a; and a second substrate 4 joined to the first substrate 1 through the electrode layer 2 and a joining resin layer 3 and has: a through hole 5 penetrating the first substrate 1 until the electrode layer 2 is exposed from the other surface 1b side of the first substrate 1; a through wiring layer 6 covering an inner side surface 5c of the through hole 5 and the electrode layer 2 in the through hole 5; and a filling resin part 7 covering the through wiring layer 6 and filling the through hole 5. The Young's modulus of a resin forming the filling resin part 7 is smaller than the Young's modulus of a resin forming the joining resin layer 3.

Description

  The present invention relates to a bonded substrate with through wiring. More specifically, the present invention relates to a bonded substrate with a through wiring having a second substrate bonded to a first substrate having a through wiring through a bonding resin layer.

  Conventionally, a semiconductor substrate having a connection electrode formed on one surface of a substrate, a through hole penetrating from the other surface of the substrate to the connection electrode, and a through electrode (through wiring) formed inside the through hole is bonded. A bonded substrate bonded to a glass plate via a material is known (Patent Document 1). The inside of the through hole is filled with resin in order to protect the through electrode layer formed on the inner wall surface of the through hole.

JP 2009-200288 A

  In the conventional bonding substrate (see FIG. 6) disclosed in Patent Document 1 or the like, a crack may occur in a connection portion formed by laminating the connection electrode 102 and the through electrode 106 at the bottom of the through hole 105 ( (See FIG. 7). Then, this crack gradually expands, and the electrical connection between the connection electrode 102 and the through electrode 106 may be broken. This is because, when a temperature change occurs in the bonding substrate, the insulating resin 107 filled in the through hole 105 expands and deforms the connection portion in which the connection electrode 102 and the through electrode 106 are laminated. Is presumed to be the cause.

  The present invention has been made in view of the above circumstances, and has a through wiring that prevents the connection portion formed by laminating the connection electrode and the through electrode from being damaged due to thermal expansion of the resin disposed in the through hole. It is an object to provide a bonded substrate.

According to a first aspect of the present invention, there is provided a bonded substrate with a through wiring, the first substrate having an electrode layer formed on one surface thereof, and the second substrate bonded to the first substrate via the electrode layer and the bonding resin layer. A junction substrate with a through wiring comprising a substrate,
A through-hole penetrating the first substrate until the electrode layer is exposed from the other surface side of the first substrate;
Inside the through hole, a through wiring layer covering the inner surface of the through hole and the electrode layer,
Covering the through wiring layer and having a filled resin portion filled in the through hole;
The Young's modulus of the resin constituting the filled resin portion is smaller than the Young's modulus of the resin constituting the bonding resin layer.

  According to the bonding substrate with through wiring of the present invention, even if the filling resin portion expands as the temperature of the bonding substrate with through wiring expands, the connection portion formed by laminating the electrode layer and the through wiring layer is sandwiched therebetween. The bonding resin layers facing each other support the connecting portion. For this reason, a deformation | transformation of a connection part is suppressed and damage to a connection part can be prevented. As a result, the reliability of electrical connection between the electrode layer and the through wiring layer can be improved.

According to a second aspect of the present invention, there is provided the bonding substrate with through wiring according to the first aspect, wherein the glass transition temperature of the resin constituting the filling resin portion is equal to or lower than the glass transition temperature of the resin constituting the bonding resin layer. It is characterized by that.
According to this configuration, even at a temperature higher than the glass transition temperature of the filling resin portion or the bonding resin layer, the relationship of “Young's modulus of the filling resin portion” <“Young's modulus of the bonding resin layer” can be reliably maintained. In general resins, Young's modulus decreases (softens) when the glass transition temperature is exceeded. Therefore, when the temperature of the bonding substrate with through wiring of the present invention rises, the filling resin portion softens before the bonding resin layer softens, so that the deformation and breakage of the connection portion due to the expansion of the filling resin portion is further increased. It can be surely prevented.

According to a third aspect of the present invention, there is provided the bonding substrate with through wiring according to the first or second aspect, wherein a passivation layer is formed on the second substrate side of the electrode layer.
According to this configuration, the electrode layer can be protected by the passivation layer and the structural strength of the electrode layer can be increased. Therefore, deformation and breakage of the connecting portion can be prevented more reliably.

According to a fourth aspect of the present invention, there is provided the bonding substrate with a through wiring according to any one of the first to third aspects, wherein the electrode layer is thinned in a region connected to the through wiring layer. Features.
According to this configuration, since the through wiring layer is inserted in the thickness direction of the electrode layer, mechanical coupling between the electrode layer and the through wiring layer is strengthened. Therefore, it is possible to more reliably prevent the connection portion from being damaged.

  According to the bonded substrate with through wiring of the present invention, it is possible to prevent the electrode from being damaged by the thermal expansion of the resin disposed in the through hole. As a result, the reliability of electrical connection between the through wiring layer and the electrode layer can be improved.

It is a schematic diagram which shows the cross section of 1st embodiment of the joining board | substrate with a penetration wiring concerning this invention. It is a schematic diagram which shows the cross section of 1st embodiment of the joining board | substrate with a penetration wiring concerning this invention. It is a schematic diagram which shows the cross section of 2nd embodiment of the joining board | substrate with a penetration wiring concerning this invention. It is a graph which shows the relationship of the stress with respect to the Young's modulus ratio of joining resin and filling resin. It is typical sectional drawing which shows an example of the manufacturing method of the joining board | substrate with a penetration wiring concerning this invention. It is a schematic diagram which shows the cross section of the conventional joining board | substrate with a through wiring. It is typical sectional drawing which shows a mode that filling resin is thermally expanding in the conventional joining board | substrate with a through-wiring.

The present invention will be described below based on preferred embodiments with reference to the drawings.
[Junction substrate 10A with through wiring]
FIG. 1 is a cross-sectional view of a bonding substrate 10A with a through wiring that is a first embodiment of the bonding substrate with a through wiring according to the present invention.

A bonding substrate 10A with a through wiring includes a first substrate 1 having an electrode layer 2 formed on one surface 1a, and a second substrate 4 bonded to the first substrate 1 via the electrode layer 2 and the bonding resin layer 3. I have.
Furthermore, the bonding substrate 10A with the through wiring includes a through hole 5 that penetrates the first substrate 1 until the electrode layer 2 is exposed from the other surface 1b side of the first substrate 1, and the inside of the through hole 5 within the through hole 5. It has a through wiring layer 6 that covers the side surface 5 c and the electrode layer 2, and a filling resin portion 7 that covers the through wiring layer 6 and is filled in the through hole 5.
Further, in the bonded substrate board 10 </ b> A with the through wiring, the Young's modulus E <b> 1 of the resin constituting the filling resin portion 7 is smaller than the Young's modulus E <b> 2 of the resin constituting the bonding resin layer 3.

The material in particular of the 1st board | substrate 1 is not restrict | limited, The material used for a well-known wiring board can be applied, for example, silicon | silicone and glass are used.
The material in particular of the 2nd board | substrate 4 is not restrict | limited, The material used for a well-known wiring board can be applied, for example, silicon, glass, resin etc. are used.
The material of the first substrate 1 and the material of the second substrate 4 may be the same or different.
The thickness in particular of the 1st board | substrate 1 is not restrict | limited, According to the use of the joining board | substrate with a through-wire of this invention, it can set suitably. For example, the thickness may be 5 μm to 300 μm.

  The material of the electrode layer 2 formed on the one surface 1a of the first substrate 1 is not particularly limited as long as it is a conductive substance, and a metal used for a known wiring board can be used. For example, copper, tin, aluminum, gold, a copper-tin alloy, etc. are mentioned.

The thickness of the electrode layer 2 is not particularly limited, and may be usually 0.1 μm to 20 μm, preferably 0.5 μm to 15 μm, more preferably 1 μm to 10 μm, and still more preferably 1 μm to 5 μm.
When it is at least the lower limit of the above range, the structural strength of the electrode layer 2 can be increased. When it is below the upper limit of the above range, the electrical resistance in electrical connection between the electrode layer 2 and the through wiring layer 6 can be reduced.

  A through hole 5 is formed in the first substrate 1. The through hole 5 penetrates from the other surface 1b of the first substrate 1 to the electrode layer 2 disposed on the first surface 1a. That is, the electrode layer 2 is disposed so as to cover the bottom 5d of the through hole 5 and serve as a lid. One end of the through hole 5 is open to the other surface 1 b of the first substrate 1.

The hole diameter, opening diameter, shape, and path of the through hole 5 are not particularly limited, and may be set as desired according to the purpose of the through hole 5.
The hole diameter may be 50 μm to 100 μm, for example. The opening diameter may be, for example, 50 μm to 100 μm.
As shown in FIG. 1, the shape may be such that the two inner side surfaces 5 c facing each other in the cross section of the through-hole 5 are parallel or non-parallel. In the case of non-parallel, it is preferably a taper shape in which the hole diameter increases from the bottom 5d of the through hole 5 toward the opening. With such a tapered shape, it becomes easier for the thermally expanded filling resin portion 7 to escape to the opening side, and the electrode layer 2 and the through wiring layer 6 disposed on the bottom portion 5d of the through hole 5 are deformed or damaged. Can be further prevented.

The ratio (aspect ratio) of “depth” / “opening diameter” of the through-hole 5 is preferably 1/1 to 20/1, more preferably 1/1 to 10/1, and 1/1 to 5/1. Is more preferable.
When the diameter is equal to or greater than the lower limit of the above range, the diameter of the through-hole 5 does not become too large, and the volume occupied by the through-hole 5 in the first substrate 1 can be reduced, and the through-hole 5 in the first substrate 1 can be reduced. Is easier to arrange.
When the thermal expansion of the filling resin portion 7 due to the temperature rise of the first substrate 1 occurs when the temperature is below the upper limit of the above range, the expanded portion of the filling resin portion 7 is defined as the opening side of the through hole 5 (first substrate). 1 on the other surface 1b side). As a result, it becomes difficult to apply stress due to thermal expansion of the filling resin portion 7 to the bottom portion 5d of the through hole 5, and the deformation and breakage of the electrode layer 2 and the through wiring layer 6 can be more reliably prevented.

In FIG. 1, the through hole 5 extends in the thickness direction of the first substrate 1. In other words, the through-hole 5 extends perpendicularly to the one surface 1a and the other surface 1b of the first substrate 1.
The through hole in the bonding substrate with through wiring according to the present invention does not necessarily extend perpendicularly to one surface and the other surface of the first substrate, and extends obliquely with respect to the one surface and the other surface of the first substrate. May be.

  The through wiring layer 6 covers the electrode layer 2 disposed on the inner side surface 5 c (inner wall surface 5 c) of the through hole 5 and the bottom portion 5 d of the through hole 5. A through wiring layer 6 is laminated on the electrode layer 2 at the bottom 5 d of the through hole 5. Since the through wiring layer 6 is connected to the surface wiring 8 disposed on the other surface 1 b of the first substrate 1, the electrode layer 2 is electrically connected to the surface wiring 8 on the other surface 1 b through the through wiring layer 6. Has been. The thickness of the through wiring layer 6 may be 0.5 μm to 10 μm, for example.

  The filling resin portion 7 fills a space not occupied by the through wiring layer 6 inside the through hole 5 and covers the surface wiring 8 on the other surface 1 b of the first substrate 1.

  The bonding resin layer 3 bonds the one surface 1 a of the first substrate 1 and the one surface 4 a of the second substrate 4. Further, the bonding resin 3 is interposed between the second substrate 4 side of the electrode layer 2 and the one surface 4a of the second substrate 4, and bonds the two together.

  The thickness of the bonding resin layer 3 is not particularly limited, and is appropriately adjusted according to the purpose of the bonding substrate with through wiring. For example, as shown in FIG. 2, when an optical device 9 or a MEMS device is formed on one surface 1a of the first substrate 1, a gap S is required above the lens of the optical device 9 or the movable mechanism of the MEMS device. There is. In this case, it is necessary to ensure the gap S by relatively increasing the thickness of the bonding resin layer 3. Since the distance between the one surface 1a of the first substrate 1 and the one surface 4a of the second substrate 4 can be increased by increasing the thickness of the bonding resin layer 3, the gap S can be expanded.

When the bonding resin layer 3 that supports the through wiring layer 6 and the electrode layer 2 is relatively thin (for example, 1.0 μm to 10 μm), the first surface 4a of the second substrate 4 supports the bonding resin layer 3 to indirectly Thus, the through wiring layer 6 and the electrode layer 2 can be supported.
On the other hand, when the bonding resin layer 3 is relatively thick (for example, 30 μm to 100 μm), since the indirect support of the second substrate 4 cannot be obtained, only the bonding resin layer 3 and the through wiring layer 6 and The electrode layer 2 is supported. In this case, the relationship between the Young's modulus of the resin constituting the bonding resin layer 3 and the Young's modulus of the resin constituting the filling resin portion 7 is particularly important.

  The resin (filling resin) constituting the filling resin portion 7 and the resin (joining resin) constituting the bonding resin layer 3 are selected so that their Young's moduli have a predetermined relationship. The predetermined relationship is “Young's modulus E1 of the bonding resin layer 3”> “Young's modulus E2 of the resin of the filling resin portion 7”. The type of each resin is not particularly limited as long as it is a combination of resins satisfying this relationship.

  Examples of suitable combinations of the resin constituting the bonding resin layer 3 and the resin constituting the filling resin portion 7 include those shown in Table 1 below. When the resin combination illustrated here is used, when the filling resin portion 7 is thermally expanded, the bonding resin layer 3 supports the through wiring layer 6 and the electrode layer 2 to prevent deformation and breakage thereof. It will be even more certain.

In the present specification and claims, the Young's modulus of each resin is measured by the method and conditions of JIS K 7163 (1994), which defines the test method for the tensile properties of plate-like and film-like resins. .
The Young's modulus of each resin varies with temperature, but the predetermined relationship is maintained as long as the glass transition temperature of each resin is not exceeded. Therefore, it is preferable to use the bonded substrate with through wiring of the present invention in the above temperature range.

In this invention, it is preferable that the glass transition temperature of resin which comprises the filling resin part 7 is below the glass transition temperature of resin which comprises the joining resin layer 3. FIG.
If the resin combination satisfies the relationship of the glass transition temperature, “Young's modulus E2 of the filled resin portion 7” <“bonding resin layer 3” even at a temperature higher than the glass transition temperature of the filled resin portion 7 or the bonding resin layer 3. The Young's modulus E1 "can be reliably maintained. In general resins, Young's modulus decreases (softens) when the glass transition temperature is exceeded. Therefore, when the temperature of the bonding substrate with through-wiring of the present invention rises, the filling resin portion 7 softens before the bonding resin layer 3 softens, so the through-wiring layer 6 due to thermal expansion of the filling resin portion 7. In addition, deformation and breakage of the electrode layer 2 can be prevented more reliably.

  Here, in the bonding substrate 10A with through wiring of FIG. 1, the filling resin portion 7 is filled in the through hole 5 having a hole diameter = 100 μm and a depth = 200 μm, the through wiring layer 6 = 5 μm, the electrode layer 2 = 1 μm, and the bonding The stress applied to the through wiring layer 6 and the electrode layer 2 due to the thermal expansion of the filled resin portion 7 when a temperature rise of 25 ° C. → 260 ° C. occurs under the condition of the resin layer 3 = 50 μm was calculated using a structural simulation. . The result is shown in FIG.

  In FIG. 3, the Young's modulus ratio represented by “Young's modulus E1 of bonding resin / Young's modulus E2 of filled resin” is plotted on the horizontal axis, and the stress when this Young's modulus ratio = 1 is used as a reference (value = 1). The stress when the Young's modulus ratio is changed is calculated, and the ratio to the reference is calculated and taken on the vertical axis.

  In FIG. 3, plot A is a case where the Young's modulus ratio = 1 (the Young's modulus of the bonding resin = 0.3 GPa / Young's modulus of the filling resin = 0.3 GPa). Plot B shows the case where the Young's modulus ratio = 5.7 (the Young's modulus of the bonding resin = 1.7 GPa / Young's modulus of the filled resin = 0.3 GPa). Plot C is a case where the Young's modulus ratio = 11.7 (the Young's modulus of the bonding resin = 3.5 GPa / Young's modulus of the filling resin = 0.3 GPa).

  From the results of FIG. 3, it can be said that the higher the Young's modulus ratio, the more the stress applied to the through wiring layer 6 and the electrode layer 2 tends to decrease. Therefore, in the bonded substrate with through wiring of the present invention, it is preferable that the Young's modulus ratio is high because deformation and breakage of the through wiring layer 6 and the electrode layer 2 can be prevented. As a suitable range of the Young's modulus ratio, 1 to 40 is preferable, 5 to 30 is more preferable, and 10 to 20 is still more preferable. When the Young's modulus ratio is smaller than 1, the effect of the present invention is hardly obtained. If the Young's modulus ratio is greater than 40, the electrode layer may be damaged by the thermal stress of the bonding resin.

[Junction substrate 10B with through wiring]
FIG. 4 is a cross-sectional view of a bonding substrate 10B with a through wiring which is a second embodiment of the bonding substrate with a through wiring according to the present invention.
In FIG. 4, the same components as those shown in FIGS.
This embodiment is different from the first embodiment described above in that a passivation layer 11 is formed on the second substrate 4 side of the electrode layer 2. The passivation layer 11 can protect the electrode layer 2 and increase the structural strength of the electrode layer 2, so that the through wiring layer 6 and the electrode layer 2 can be more reliably prevented from being deformed and damaged.

Examples of the material constituting the passivation layer 11 include SiN, SiO ₂ , polyimide, and PBO. Among these, a material having a large Young's modulus such as SiN or SiO ₂ is preferable because deformation of the electrode layer can be suppressed.

  In the present invention, the electrode layer 2 is preferably thinned in a region where the electrode layer 2 is connected to the through wiring layer 6.

<Manufacturing method of bonded substrate with through wiring>
A method for manufacturing a bonded substrate with a through wiring according to the present invention will be described with reference to FIG.
An insulating layer 12 made of SiO ₂ is formed on one surface 1a made of silicon on which a device (not shown) is formed by plasma CVD using TEOS or the like. Next, an electrode layer 2 made of copper is formed at a predetermined position of the insulating layer 12 by sputtering or photolithography. Thereafter, if necessary, a passivation layer may be formed by CVD or the like.
Subsequently, a bonding resin is applied to one surface 1a of the first substrate 1 by a screen printing method or the like, and further, one surface 4a of the second substrate 4 made of quartz glass is bonded to the coating surface, thereby obtaining a thickness of 10 to 10. A bonding resin layer 3 having a thickness of 50 μm is formed (FIG. 5A). Thereafter, the first substrate 1 is thinned by polishing the other surface 1b of the first substrate 1 as necessary.

Next, a mask made of a photosensitive resin having a desired pattern is formed on the other surface 1b of the first substrate 1 (not shown), and the through hole 5 is formed by a dry etching method using an etching gas such as CF ₄ or SF _6. Form. Thereby, the electrode layer 2 formed on the one surface 1a of the first substrate 1 is exposed at the bottom 5d of the through hole 5 (FIG. 5B). At this time, the electrode layer 2 located at the bottom of the through hole 5 is preferably etched somewhat in the thickness direction. Thereby, the surface impurities of the electrode layer 2 are removed, so that the electrical connection reliability between the electrode layer 2 and the through wiring layer 6 can be improved. Further, since the through wiring layer is inserted in the thickness direction of the electrode layer, the mechanical coupling between the electrode layer and the through wiring layer is strengthened.
Next, an insulating layer 13 made of SiO ₂ is formed on the inner side surface 5c of the formed through hole 5 and the other surface 1b of the first substrate 1 by plasma CVD using TEOS (FIG. 5C).

  Subsequently, a barrier layer made of titanium, chromium, titanium-tungsten alloy or the like and a plating seed layer made of copper (not shown) are formed by sputtering or the like, and the through wiring layer made of copper is made by electrolytic plating or the like. 6 is formed. At this time, the surface wiring 8 may be formed on the other surface 1b of the first substrate 1 as necessary (FIG. 5D).

A filling resin portion 7 is formed by arranging a filling resin in a space in which the through hole 5 is vacant and a desired region of the other surface 1b of the first substrate 1 by a vacuum printing method or a vacuum laminating method (FIG. 5 (e)). )).
By the above manufacturing method, 10 A of bonded substrates with a through wiring concerning this invention are obtained.

DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 1a ... One surface of 1st substrate, 1b ... Other surface of 1st substrate, 2 ... Electrode layer, 3 ... Bonding resin layer, 4 ... Second substrate, 4a ... One surface of 2nd substrate, 5 ... Through hole, 5c ... inner surface (inner wall surface) of the through hole, 5d ... bottom of the through hole, 6 ... through wiring layer, 7 ... filled resin portion, 8 ... surface wiring, 9 ... device, 10A, 10B ... Bonding substrate with through wiring, 11 ... Passivation layer, 12 ... Insulating layer, 13 ... Insulating layer, 100 ... Conventional bonding substrate with through wiring, 101 ... Semiconductor substrate, 102 ... Electrode pad, 103 ... Adhesive, 104 ... Glass substrate , 105 through-hole, 106 wiring layer, 107 wiring protective resin

Claims (4)

A first substrate having an electrode layer formed on one surface, and a bonding substrate with a through-wiring comprising a second substrate bonded to the first substrate via the electrode layer and a bonding resin layer,
A through-hole penetrating the first substrate until the electrode layer is exposed from the other surface side of the first substrate;
Inside the through hole, a through wiring layer covering the inner surface of the through hole and the electrode layer,
Covering the through wiring layer and having a filled resin portion filled in the through hole;
A bonding substrate with through wiring, wherein a Young's modulus of a resin constituting the filling resin portion is smaller than a Young's modulus of a resin constituting the bonding resin layer. The bonding substrate with through wiring according to claim 1, wherein a glass transition temperature of a resin constituting the filling resin portion is equal to or lower than a glass transition temperature of a resin constituting the bonding resin layer. The passivation substrate with through wiring according to claim 1, wherein a passivation layer is formed on the second substrate side of the electrode layer. The junction substrate with through wiring according to claim 1, wherein the electrode layer is thinned in a region connected to the through wiring layer.

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