TW202305973A - Glass substrate, and glass interposer - Google Patents

Abstract

To provide a glass substrate and a glass interposer using the glass substrate that enable a narrower glass interposer pitch to be realized while suppressing manufacturing costs. A glass substrate 12 has a plurality of through-holes 126. The glass substrate 12 comprises: a wiring filling recess 128 that is provided in a planned wiring formation position on a main surface; and a through wiring section 122 and an in-plane wiring section 124 that are made of a conductive material and arranged in the through-holes 126 and the wiring filling recess 128, respectively. The top surface of the in-plane wiring section 124 and the main surface of the glass substrate 12 are arranged on the same plane and each have a smooth surface.

Description

Glass substrate and glass interposer

The present invention relates to a glass substrate and a glass interposer using the glass substrate.

In the past, as the material of the interposer, silicon-based materials or resin-based materials have been widely used.

However, when considering the narrowing of the pitch of the connection pads (bumps) and the miniaturization of wiring, silicon-based materials have the disadvantage of increasing production costs, and resin-based materials are difficult to achieve. Miniaturization such disadvantages.

Therefore, in the prior art, there is a technique of using a glass material to form a glass interposer (for example, refer to Patent Document 1). According to this technology, a technical problem peculiar to glass such as metallization is solved, and a suitable glass interposer can be realized. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2019-044212

[Problems to be Solved by the Invention]

However, since the conventional glass interposer including the above-mentioned Patent Document 1 forms a multilayer wiring layer composed of a plurality of materials other than glass on a glass substrate, the pitch of the connection pads (bumps) may be narrowed and Miniaturization of wiring becomes difficult.

For example, there are disadvantages in that warpage occurs due to the difference in thermal expansion coefficient between the glass and the multilayer wiring layer, or that the multilayer wiring layer is deformed by external force during lamination.

Furthermore, when the multilayer wiring layer is made of resin, it is difficult to miniaturize as described above, and since the process for forming the multilayer wiring layer involves many steps, the production cost tends to increase.

The object of the present invention is to provide a glass substrate that "can realize narrow pitch of glass interposer while suppressing production cost" and a glass interposer using the glass substrate. [Means to solve the problem]

The glass substrate of the present invention has a plurality of fine through holes. The diameter of the fine through hole is in the range of about 5 μm to 500 μm, and is formed by, for example, laser-assisted etching.

This glass substrate is equipped with the recessed part for wiring filling, and a wiring part. The wiring filling recess is provided at a position where wiring is to be formed on the main surface of the glass substrate. Examples of the wiring-filling recess include fine grooves in which fine wiring is arranged, recesses extending so as to cover a desired region, and the like, but are not limited thereto.

The wiring part is made of a conductive material represented by a metal material such as copper or chromium, and is respectively arranged in the fine through-hole and the concave part for wiring filling.

Among the wiring portions, the upper surface of the wiring portion disposed in the wiring filling concave portion and the main surface of the glass substrate are disposed on the same plane and each has a smooth surface. In order to realize such a structure, it is preferable to polish the whole area|region of the main surface of a glass substrate by chemical mechanical polishing process etc., for example after filling a wiring part in the recessed part for wiring filling.

In the above configuration, the surface roughness Ra of the smooth surface of the upper surface of the wiring portion disposed in the wiring filling recess and the smooth surface of the main surface of the glass substrate should be 10 nm or less, preferably 1 nm or less.

The reason for this is that the higher the smoothness of the principal surfaces of the glass substrates, the easier it is to bond the glass substrates together to form the glass interposer. Furthermore, when the surface roughness Ra of the smooth surface is smoothed to 0.5 nm or less (more preferably 0.1 nm or less) by chemical mechanical polishing or the like, glass substrates can be easily bonded by bonding at room temperature.

By "improving the adhesion between a plurality of glass substrates, and stacking them to form an interposer with a multilayer wiring structure", it is possible to form at low cost without warpage caused by thermal expansion, and it is not easy to cause warping due to thermal expansion. Multilayer wiring structure deformed by external force.

In particular, since glass substrates are easy to realize large-scale and ultra-thin, compared with the case of using other materials such as resin, ceramics, and silicon, it is easier to suppress the cost of producing narrow-pitch interposers. [Effect of Invention]

According to this invention, the pitch of the glass interposer can be narrowed while suppressing the production cost.

1(A) to 1(D) schematically show a glass interposer 10 as an embodiment of the present invention. The glass interposer 10 is supported by the probe card 2 so that its position can be adjusted freely. In this embodiment, an example in which the glass interposer 10 is used in the probe card 2 is described, but the glass interposer 10 can be used in other applications such as a semiconductor memory.

The probe card 2 is attached to a needle tester 4 which is configured to be connected to a tester or the like and to be able to move freely. The probe card 2 is configured to measure the electrical characteristics of a measurement object 6 (for example, a silicon wafer on which a semiconductor integrated circuit is formed) on a platform (not shown).

A probe supporting substrate 8 is connected to the main surface of the glass interposer 10 that faces the measurement object 6 . The probe supporting substrate 8 has a plurality of probes 9 . In addition, the probes 9 are shown only for convenience of illustration. The probe supporting substrate 8 is made of resin, ceramics, silicon, etc. having a plurality of through holes, but similarly to the glass interposer 10, a glass member may also be used.

The glass interposer 10 is configured such that the pitch of the probes 9 provided on the probe supporting substrate 8 is adapted to the pitch of spring electrodes 7 provided on the probe card 2 . Specifically, it is configured so that the connection pads 70 and 90 having different arrangement pitches shown in FIG. 1(B) are electrically connected.

As shown in FIG. 1(B), the glass interposer 10 is formed by laminating a plurality of glass substrates 12 . In this embodiment, the glass interposer 10 is formed by bonding three glass substrates 12 at room temperature, but the number of glass substrates 12 and the bonding method are not limited to these.

Since the glass substrates 12 constituting the glass interposer 10 have substantially the same configuration, a single glass substrate 12 will be described here for convenience.

As shown in FIG. 1(C) and FIG. 1(D), the glass substrate 12 is provided with: a through-wiring portion 122 disposed on the inner wall surface of a through-hole 126; and an in-plane wiring portion 124 as a circuit pattern, The opening of the through hole 126 is provided at a predetermined portion of the main surface of the glass substrate 12 . The in-plane wiring portion 124 is arranged so as to be filled in the wiring filling concave portion 128 .

In this embodiment, the penetrating wiring portion 122 and the in-plane wiring portion 124 are both composed of copper plating, but they are not limited to this as long as they are conductive layers. With the above-mentioned through wiring portion 122, in-plane wiring portion 124, connection pad 70, connection pad 90, and conductive paste (silver, chromium, silicon nitride, etc.) provided in or near the through hole 126 as required, Electrically connect the probe 9 and the spring electrode 7 .

In the glass substrate 12, the upper surface of the in-plane wiring portion 124 in the wiring filling recess 128 is arranged on the same plane as the main surface of the glass substrate 12, and the upper surface of the in-plane wiring portion 124 is aligned with the main surface of the glass substrate 12. Each surface is subjected to surface treatment so that the surface roughness 1Ra becomes 1 nm or less.

The reason for employing such a configuration is that it is easy to bond the glass substrates 12 to each other. If there are irregularities on the bonding surface of the glass substrate 12, it becomes difficult to form the glass interposer 10 by laminating the glass substrates 12. The method of smoothing facilitates bonding of the glass substrates 12 . For example, when the glass substrates 12 are bonded by bonding at room temperature, the surface roughness 1Ra is 1 nm or less, more preferably about 0.1 nm to 0.5 nm, and still more preferably 0.1 nm or less. Moreover, even when using an adhesive agent etc., it is preferable that the glass substrate 12 has the smoothness of about 10 nm or less of surface roughness.

Next, an example of the method of manufacturing the glass substrate 12 is demonstrated using FIG.2(A) - FIG.2(E). First, as shown in FIGS. 2(A) to 2(B), a wiring filling recess 128 is provided at a circuit pattern formation position on the main surface of the glass substrate 12 . The wiring filling recess 128 is formed, for example, by "selective etching using a photoresist, a chrome mask, or an etch-resistant film".

Thereafter, as shown in FIG. 2(C), through-holes 126 are provided. The through hole 126 is formed by so-called laser-assisted etching or the like. In this embodiment, the through hole 126 is formed with a diameter of about 50 μm to 100 μm, but the diameter of the through hole 126 can be appropriately set to a range of about 5 μm to 500 μm by adjusting the beam diameter of the laser light.

Next, as shown in FIG. 2(D), the penetrating wiring portion 122 and the in-plane wiring portion 124 are formed. Here, after forming a copper seed layer of about 1 μm by electroless copper plating, a copper plating layer of 50 to 60 μm is formed by electrolytic plating. And, if necessary, conductive paste such as chromium is filled in the through holes 126 .

However, the method of forming the penetrating wiring portion 122 and the in-plane wiring portion 124 is not limited to this. For example, regarding the through wiring portion 122 and the in-plane wiring portion 124 , a method of forming an adhesive layer of Ti or TiW or the like and a copper seed layer by sputtering may also be employed. Moreover, when forming a copper seed layer, metal oxide film formation or primer by a sol-gel method (Sol-Gel method) can also be used.

Furthermore, as shown in FIG. 2(E), the entire main surface of the glass substrate 12 including the upper surface of the in-plane wiring portion 124 is subjected to surface treatment by CMP (Chemical Mechanical Polishing) treatment, that is, a chemical mechanical polishing treatment. .

In this embodiment, the effect of the relative movement between the main surface of the glass substrate 12 and the slurry is increased by the surface chemical action of the abrasive (abrasive grain) such as SeO and the action of the chemical composition contained in the slurry. To the mechanical grinding effect. As a result, it is possible to obtain a smooth polished surface having a surface roughness 1Ra of 0.1 nm or less for bonding at room temperature.

The glass substrate 12 subjected to the CMP treatment on the main surface is bonded at room temperature, and the required number is laminated to form the glass interposer 10 . As a method of bonding at room temperature, known bonding methods such as a surface activation method and an atomic diffusion bonding method are exemplified.

FIGS. 3(A) to 3(C) show an aspect in which the wiring filling recess 128 is formed on the main surface of the glass substrate 12 described using FIG. 2(B).

Here, first, as shown in FIG. 3(A), an etching-resistant photoresist 30 is applied to the main surface of the glass substrate 12, and the photoresist 30 at a desired position is removed by exposure and development. Thereby, the formation position of the wiring filling recessed part 128 is exposed.

Thereafter, as shown in FIG. 3(B), a desired position of the glass substrate 12 is dissolved by etching, thereby forming the wiring filling recess 128 . Then, as shown in FIG. 3(C) , after forming the wiring filling recess 128 , the photoresist 30 is removed. In addition, instead of processing with the photoresist 30, after affixing an etch-resistant film on the main surface of the glass substrate 12, laser processing may be used to remove the film at a desired position, thereby making the concave portion for wiring filling The formation positions of 128 are exposed or processed by chrome masking or other methods to perform the same treatment.

4(A) and 4(B) show an example of a method for forming the through-hole 126 in the glass substrate 12 . Here, a laser beam is irradiated to a position in the glass substrate 12 where the through hole 126 should be formed, thereby forming a modified portion that is easily etched at the position.

The type and irradiation conditions of the laser beam are not particularly limited as long as the planned position of the through hole 126 in the 12 can be modified to be easily etched. In this embodiment, a laser beam oscillated by a short-pulse laser (such as a picosecond laser or a femtosecond laser) is irradiated from the laser head, but for example, a _CO2 laser or a nanosecond laser can also be used. Shoot and so on.

In addition, in this embodiment, the output control is performed so that the average laser energy of the laser beam becomes approximately 30 μJ to 300 μJ, but the present invention is not limited thereto.

For the laser beam, it is better to properly adjust its focusing area. Here, the focusing area of the laser beam is adjusted to cover the entire area in the thickness direction of the glass substrate 12, whereby the through hole 126 can be easily formed.

Following the above-mentioned laser processing, the through-hole 126 is formed in the glass substrate 12 by etching the above-mentioned modified portion.

For the etching process, for example, an etching apparatus 50 using a leaf-type spray etching method as shown in FIG. 5(A) and FIG. 5(B) is used. The glass substrate 12 is introduced into the etching apparatus 50, and is subjected to an etching process by applying an etching solution containing hydrofluoric acid, hydrochloric acid, or the like. Usually, an etching solution containing 1 to 10% by weight of hydrofluoric acid and 5 to 20% by weight of hydrochloric acid is used, and a surfactant or the like is used in combination as needed.

In the etching device 50, as shown in FIG. 5(A) and FIG. 5(B), while the glass substrate 12 is being transported by the transport rollers, the etchant is brought into contact with the main surface of the glass substrate 12 in the etching chamber 52, Thereby, the etching process with respect to the glass substrate 12 is performed.

Since the rear stage of the etching chamber 52 in the etching device 50 is provided with a cleaning chamber 53 for rinsing the etching solution attached to the glass substrate 12, the glass substrate 12 is removed from the etching solution. It is discharged from the etching device 50 .

In this way, by using laser processing to assist etching, the etching process time can be minimized to the limit.

As a result, the surface of the glass substrate 12 becomes less likely to be roughened and the shape of the through-hole 126 becomes less likely to be deformed when the through-hole 126 is formed. The diameter of the through hole 126 can be appropriately adjusted to a range of about 5 μm to 500 μm.

In principle, if the thickness of the glass substrate 12 is thin, the diameter of the through hole 126 can be easily reduced. The reason is that during the etching process, the diameter of the through hole 126 is slightly increased compared with the diameter of the laser beam.

As a countermeasure against microincreasing, the applicant's experiments have clarified the following: in the etching process, adding a fluorine complexing agent such as titanium oxide or an alkali such as potassium hydroxide or sodium hydroxide, thereby, the etching process The slight increase in the groove width of the through hole 126 is suppressed. Therefore, an appropriate amount of fluorine complexing agent or alkali is added to the etching solution as needed, thereby adjusting the diameter or shape of the through hole 126 .

Next, as shown in FIG. 6(A) and FIG. 6(B), formation processing of the penetrating wiring portion 122 and the in-plane wiring portion 124 and CMP processing on the glass substrate 12 are performed. As mentioned above, here, after forming the copper seed layer of about 1 micrometer by electroless copper plating, the copper plating layer of 50-60 micrometers is formed by electrolytic plating.

In addition, when the diameter of the through-hole 126 exceeds 100 μm, there is a tendency that “it is difficult to fill the through-hole 126 with a conductive material only by electrolytic plating”. It is preferable to fill the through hole 126 . Usually, a copper plating layer having a thickness approximately 1.1 to 1.5 times the thickness of the copper plating layer in the through hole 126 is formed on both main surfaces of the glass substrate 12 .

Furthermore, as shown in FIG. 2(E), the entire main surface of the glass substrate 12 including the upper surface of the in-plane wiring portion 124 is subjected to surface treatment by CMP (Chemical Mechanical Polishing) treatment, that is, a chemical mechanical polishing treatment. .

In this embodiment, the effect of the relative movement between the main surface of the glass substrate 12 and the slurry is increased by the surface chemical action of the abrasive (abrasive grain) such as SeO and the action of the chemical composition contained in the slurry. To the mechanical grinding effect. As a result, the surface roughness 1Ra can be adjusted to a range from 10 nm to less than 0.1 nm, and a smooth polished surface sufficient for bonding at room temperature can be obtained.

The glass substrate 12 subjected to the CMP treatment on the main surface is bonded at room temperature, and the required number is laminated to form the glass interposer 10 .

According to the above-mentioned embodiment, it is possible to appropriately form micropores or metallize the glass substrate, and also realize the glass interposer 10 corresponding to the narrowing of the pitch of the connection pads at low cost.

By appropriately using the above-mentioned laser-assisted etching for contour processing, even if the glass substrate 12 has a special shape (such as a polygon with rounded corners, a circle, an ellipse, etc.), the contour can be appropriately processed. .

In the above-mentioned embodiment, an example in which the etching process is performed by the etching apparatus 50 of the spray etching method was shown, but it is not limited thereto. For example, as shown in FIG. 7(A) , it is also possible to adopt a configuration of "transporting the glass substrate 12 while being in contact with the overflowing etching solution in the overflow type etching chamber 54".

Furthermore, as shown in FIG. 7(B), immersion etching of "soaking a single or a plurality of glass substrates 12 accommodated in a carrier in an etching tank 56 accommodating an etching solution" may also be used.

Of course, as shown in this figure, the shape of the glass substrate 12 is not only a circle, but also a square. Moreover, by preparing a jig suitably, it can also correspond to the glass substrate 12 of all shapes.

When the size of the glass substrate 12 is small and there is a possibility that transportation or handling may be hindered, a mesh member having etching resistance may be used as a carrier member such as a supporting tray, a basket, or a jig.

Also, as shown in FIGS. 8(A) to 8(C), laser-assisted etching may be used to simultaneously form the through hole 126 and the wiring filling recess 128 .

In this case, as shown in FIG. 8(A), by "irradiating the laser beam while adjusting the focus of the laser", the area in the glass substrate 12 where the concave portion 128 for wiring filling should be formed is modified. quality.

And, as shown in FIG. 8(B), the position of the through hole 126 is modified by the laser beam. Then, as shown in FIG. 8(C), the modified portion is dissolved by etching, whereby the through hole 126 and the wiring filling recess 128 are simultaneously formed.

It should be thought that the description of the above-mentioned embodiment is an illustration and restrictive at no points. The scope of the present invention is not shown by the above-mentioned embodiments but by the claims. In addition, it is intended that all modifications within the meaning and range equivalent to the scope of claims are included in the scope of the present invention.

10: Glass interposer 12: Glass substrate 122: Through wiring part 124: In-plane wiring part 126: Through hole 128: Recess for wiring filling

[ Fig. 1 ] A diagram showing a schematic configuration of a glass interposer according to an embodiment of the present invention. [ Fig. 2 ] A diagram showing an example of a method of manufacturing a glass interposer. [ Fig. 3] Fig. 3 is a diagram showing an example of a method of forming a wiring filling recess. [ Fig. 4 ] A diagram showing an example of a method of forming a through-hole. [ Fig. 5 ] A diagram showing an example of an etching apparatus used in the production of a glass interposer. [FIG. 6] A diagram showing an example of a method of forming a through wiring portion and an in-plane wiring portion. [ Fig. 7] Fig. 7 is a diagram showing another example of an etching apparatus used in the production of a glass interposer. [ Fig. 8] Fig. 8 is a diagram showing another example of a method of forming a wiring filling recess and a through hole.

2: Probe card

4: Needle measuring machine

6: Measurement object

7: Spring electrode

8: Probe support substrate

9: Probe

10: Glass interposer

12: Glass substrate

70: connection pad

90: connection pad

122: Through wiring part

124: In-plane wiring part

126: Through hole

128: Recess for wiring filling

Claims (3)

A glass substrate having a plurality of fine through holes, the glass substrate is characterized by at least: The concave portion for filling wiring is provided at a predetermined wiring formation position on the main surface of the glass substrate; and The wiring portion is made of a conductive material respectively disposed in the fine through hole and the wiring filling recess, The upper surface of the wiring portion arranged in the above-mentioned wiring filling concave portion and the main surface of the glass substrate are arranged on the same plane and each has a smooth surface. The glass substrate of claim 1, wherein, The surface roughness Ra of the smooth surface of the upper surface of the wiring portion disposed in the wiring filling recess and the smooth surface of the main surface of the glass substrate is 1 nm or less, respectively. A glass interlayer formed by bonding a plurality of glass substrates according to claim 1 or 2.

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