JP2673928B2 - Lid for sealing electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CCD (Charge Coupled).
The present invention relates to a lid member for encapsulating an electronic component used when a solid-state imaging device such as a device) is housed in a package and hermetically sealed.

[0002]

2. Description of the Related Art Conventionally, when an electronic component element such as a CCD or MOS solid-state image pickup element is housed and fixed in a ceramic package and hermetically sealed, an organic or inorganic adhesive is used. Install the lid substrate pre-coated with the agent so as to close the opening of the ceramic package, and as it is or while pressing with a clip etc.,
A method is adopted in which it is heated to melt the adhesive to bond the package and the lid substrate.

When the package and the lid substrate are bonded together, if the thickness of the adhesive is uniform, the pressure of the gas existing inside the ceramic package rises due to the heat applied when the adhesive is melted, and the lid body The airtightness between the substrate 1 and the ceramic package may be impaired. Specifically, when the gas in the ceramic package escapes to the outside, gas escape holes, that is, cavities, may be formed in the adhesive layer.

In order to eliminate the defects caused by using such an adhesive layer having a uniform thickness, as shown in FIG. 5, an adhesive layer provided with slits 3 as gas vents is provided. 2 was used. In this case, the lid substrate 1 is provided with an adhesive layer 2 made of an adhesive in an arbitrary pattern, and the adhesive layer 2 is provided with slits 3 at several positions.

FIG. 6 is a sectional view showing the adhesive layer 2 when the lid substrate 1 is cut along the line AA 'in FIG. 5, and shows the sectional shape of the slit 3. As described above, conventionally, no adhesive is applied to the bottom of the slit 3, and the adhesive is melted by heat so that the surrounding adhesive is staggered and the slit 3 is filled to perform hermetic sealing. Was there.

However, when the shape of the slit 3 is incomplete, that is, when the slit 3 does not have a sufficient gap to allow the pressurized gas inside to escape to the outside, the pressurized gas is slit. However, the airtightness between the lid substrate 1 and the ceramic package may be impaired because the adhesive layer 2 forms a nest and then escapes.

When filling the slit 3, the slit 3
When the adhesive layer 2 on the periphery is shouldered to bring the adhesive into contact with the slit bottom portion 4, since the wettability of the adhesive to the lid substrate 1 is low, the adhesive cannot close the slit 3 densely, In some cases, minute cavities were formed and the airtightness of the other adhesive layer 2 was inferior. As a result, the reliability of the entire device may be reduced.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an electronic component element encapsulation capable of completely hermetically sealing a ceramic package without forming a cavity or the like in the adhesive layer. The purpose is to provide a lid material for stopping.

[0009]

In the lid member for encapsulating electronic component elements of the present invention, the adhesive layer is formed in a thickness of 5 μm or more on the entire peripheral portion of the lid substrate, and the thickness of the lowest point is 0.1 μm or more,
Further, the above object was achieved by forming slits having a thickness of 3/4 or less of the thickness of the adhesive layer in at least one position or more of the adhesive layer.

FIG. 1 is a schematic view showing a cross section of a lid member for sealing electronic component elements according to the present invention. In FIG. 1, reference numeral 1 indicates a lid material substrate. Reference numeral 2 indicates an adhesive layer, and its thickness is indicated by Hp. The adhesive layer 2 is provided with a slit 3, and the thickness of the adhesive layer 2 (hereinafter, abbreviated as the lowest point) at the position where the slit 3 is formed most deeply is indicated by hs. ing.

As is apparent from FIG. 1, the thickness of the lowest point of the adhesive layer 2 constituting the present invention is not zero. That is, the pattern of the adhesive layer 2 is not discontinuous and is formed over the entire circumference of the lid material substrate 1.

In the adhesive layer 2 of the present invention, the above Hp is preferably 5 μm or more. If it is thinner than 5 μm, the lid substrate 1
This is because it is difficult to completely hermetically seal the ceramic package and the ceramic package.

Hs constituting the slit is 0.1 μm
It is necessary that it is not less than 3/4 of the thickness of the adhesive layer. If the thickness is less than 0.1 μm, a problem of wettability may occur due to repellency of the adhesive to the lid material substrate 1 and, as a result, the adhesive may not sufficiently fill the slits 3, particularly the lowest points of the slits 3. Therefore, it is not preferable. If it is thicker than 3/4 of the thickness of the adhesive layer 2, the gap between the slits 3 may not be sufficient for the internal gas to escape, which is not preferable.

The adhesive used is Japanese Patent Application No. 3-81305.
As disclosed in the publication, it is preferable that the thermosetting resin and the curing agent are the main components, and the Vickers hardness at 25 ° C. is a semi-cured state of 0.2 to 10.0.

Preferred thermosetting resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, phenolvolac type epoxy resin, cresol novolac type epoxy resin, and glycidyl ether type epoxy resin. It can be illustrated. These resins may be used alone or in combination.

Preferred curing agents include amine compounds such as dicyandiamide and imidazole, aromatic acid anhydrides, aliphatic acid anhydrides, and phenols. These compounds may be used alone or in combination.

In addition to the above-mentioned curable resin and curing agent, a filler can be used. Examples of fillers include inorganic powders such as silica, quartz powder, alumina, calcium carbonate, and magnesium oxide, but any substance that has a filling function can be used. You can

The hardness of the adhesive is preferably 0.2-10.0 in Vickers hardness, more preferably 0.6-.
3.0. If the Vickers hardness is less than 0.2,
The viscosity of the adhesive when melted is very low. Then, when the gas existing in the space sealed by the package and the glass expands due to heat to become a pressurized gas and escapes to the outside,
It is easy to form a nest in the adhesive layer 2. Therefore, the lid substrate 1 and the ceramic package may not be hermetically sealed, which is not preferable. Further, when the Vickers hardness of the adhesive is 10.0 or more at 25 ° C., the viscosity does not become so low that it spreads at the interface with the ceramic package even when it is in a molten state by heat. Then slit 3
It is difficult to bury the adhesive with an adhesive, which is not preferable.

Further, as disclosed in Japanese Patent Application No. 3-131055, when attention is paid to the moisture resistance of the electronic component element, the thermosetting resin has a viscosity of 100 to 3 at 25 ° C.
0,000 centipoise, especially 1,000-50,
It is preferable to use a bisphenol A type epoxy resin or a bisphenol F type epoxy resin which is 000 centipoise. If it is lower than 100 centipoise, a thickening component, for example, a filler such as a pigment must be excessively added to the resin to adjust the viscosity. As a result, the adhesive strength of the resin, which is the adhesive, and the moisture resistance may deteriorate, which is not preferable. On the other hand, if it is higher than 300,000 centipoise, the viscosity of the resin in the molten state is too high and the workability at the time of applying to the lid material substrate 1 is deteriorated, which is not preferable.

Next, a method for forming the lid member for encapsulating an electronic component according to the present invention, which is already shown in FIG. 1, will be described.
First, preferably, a liquid adhesive is prepared by mixing the above-mentioned resin as a main component and substances necessary for obtaining desired characteristics. Then, the liquid adhesive obtained on the lid material substrate 1 is applied to a predetermined region by screen printing, dispense printing or the like. Then, the slit 3 having the above thickness is formed on the formed pattern by a method such as pressing to obtain the adhesive layer 2.

As a method for forming the adhesive layer 2, in addition to the above method, for example, the frame-shaped adhesive layer 2 having a desired thickness is arranged on the lid material substrate 1, and then the slit 3 is formed by a pressing means. A method of forming a slit, a method of forming a sheet-shaped adhesive layer 2 having a desired thickness on the lid material substrate 1, punching out the central portion of the adhesive layer 2, and forming a slit 3 by a pressing means. Slit 3 which is cut off
Is formed in several places, and then the adhesive layer 2 is heated to be staggered to form slits 3 having a desired hs. It is possible to exemplify that the slit 3 is formed by controlling the thickness of the adhesive layer 2 by distinguishing between a place to be applied a plurality of times and a place to be applied less times.
Any method may be used as long as it can obtain the adhesive layer 2 described above.

The lid substrate 1 is made of glass, quartz, translucent thermosetting resin, or translucent thermoplastic resin, and the electronic component element housed in the ceramic package is a solid-state image sensor. In some cases, the adhesive layer 2 that constitutes the present invention is particularly effective. The reason will be described below. For example, the lid material substrate 1 used when accommodating an electronic component element that does not require optical characteristics is often made of ceramic or metal and has a relatively large surface roughness.
Therefore, the effect of improving the adhesiveness, which is generally called the "anchor effect", is recognized. Therefore, when a substance having a relatively large surface roughness is a partner, it is easy to obtain sufficient adhesion. However, when the electronic component element to be housed is a solid-state image sensor, the lid material substrate 1 is required to have optical characteristics, and therefore the surface roughness (center line average roughness) of the lid material substrate 1 is also 0.1 μmRa. Since it is very low as below, the above "anchor effect" cannot be expected. Therefore, it is particularly preferable to use the lid member for sealing an electronic component element of the present invention.

The lid material substrate 1 used preferably has a shape having chamfered portions X and Y, as shown in FIG. Specifically, the thickness T of the lid material substrate is 0.3 to 2.0 mm, and the height A and the width B of the chamfered portion X formed by the side surface of the lid material substrate 1 in contact with the adhesive layer 2 and the side surface thereof.
However, both are preferably in the range of 0.05 to 0.2 mm.

If the thickness of the lid material substrate 1 is less than 0.3 mm, the strength of the lid material becomes low, which causes a problem in practical use.
If it is thicker than 0.20 mm, the volume of the package becomes too thick and it becomes difficult to downsize the device, which is not preferable. In particular, when the electronic component element is a solid-state image pickup element, the lid material substrate 1 is required to have optical characteristics, which is not preferable.

The height A and width B of the chamfer are 0.05
If it is less than mm, chipping tends to occur, which is not preferable.
On the other hand, if it is larger than 0.20 mm, the space between the lid material substrate 1 and the adhesive layer 2 is likely to peel off, which is not preferable.

The above Vickers hardness means LIS
Using a light load micro hardness tester suitable for B 7734, JI
It means the hardness measured by the test method according to S Z 2251.

[0027]

In the lid member for encapsulating an electronic component according to the present invention, the adhesive layer is formed with a thickness of 5 μm or more on the entire periphery of the lid substrate.
Slits having a thickness of 0.1 μm or more at the lowest point and 3/4 or less of the thickness of the adhesive layer are formed in at least one place of the adhesive layer. Since a thin adhesive layer is also provided at the lowest point of the slit in this way, when the adhesive layer around the slit melts due to heat, causing shoulder shoulders and filling the slit in the recess, the melted adhesive does not Since it comes into contact with the melted adhesive located near the lowest point, wettability such as cissing to the lid material substrate does not become a problem.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The lid member for sealing electronic component elements of the present invention will be described in detail below with reference to the drawings. The same components as those of the conventional example are designated by the same reference numerals to simplify the description.

A mixture having the following composition was prepared as an adhesive. The composition is: epoxy resin (bisphenol A type, molecular weight: about 900) 100 parts by weight, 2-ethyl-4-methylimidazole 5 parts by weight, fine powder silica (manufactured by Degussa, trade name: AEROSIL 380) 15 parts by weight Part ・ Methyl ethyl ketone

The above-mentioned 2-ethyl-4-methylimidazole is added as a curing agent, and finely divided silica is added as a filler. Since methyl ethyl ketone is added as a diluting solvent, the addition amount is appropriately adjusted. The mixture having the above composition was sufficiently kneaded and used as an adhesive.

Then, a glass plate (made by Corning, trade name: # 7059, size: 12) that has been cleaned after precision polishing
An adhesive layer 2 having a width of 1.6 (mm) and a height of Hp (μm) using the obtained adhesive at a predetermined position of the lid material substrate 1 having a size of × 12 × 0.7t (mm)). Is provided by the screen portion. After that, slits 3 having a thickness hs (μm) were formed at predetermined positions on the adhesive layer 2. Then, preheating was performed to remove the solvent and the adhesive was semi-cured to obtain lid materials used in Examples and Comparative Examples. Note that H
Various lid materials were obtained by changing the values of p and hs.
The values of Hp and hs at this time are collectively shown in Table 1.

Next, the package was sealed using the above-mentioned lid material. As shown in FIGS. 3 and 4, the adhesive layer 2 provided on the lid material substrate 1 is placed at a predetermined position so as to come into contact with the alumina ceramic package 6 containing the electronic component elements. It was placed and heated at 150 ° C. for 4 hours while applying a load of 1 kg, and the alumina ceramic package 6 was hermetically sealed using the lid member.

Then, a gross leak test and a visual inspection using a stereoscopic microscope were carried out, and it was confirmed whether or not there was a sealing defect by confirming the presence or absence of cavities. Regarding the adhesive layer 2 which was confirmed to have no nest in these inspections, a reliability test by a pressure cracker test was further performed.

What is this pressure cracker test?
Under the environment of 121 ° C., 10% RH, and 2 atm, the package 6 having the adhesive layer 2 that has passed the above test is formed into two.
This is a test in which it is left for 4 hours and 36 hours, then returned to room temperature, the one in which the presence of dew condensation is confirmed is a poor reliability, and the one in which no dew condensation is confirmed is a good reliability.

Table 1 shows the test results and the values of Hp and hs. These tests consist of 20 pieces per lot,
And 14 packages 6 were used.

[0036]

As is clear from Table 1 above, the lid material substrate 1
An adhesive layer 2 having a thickness of 20 μm or more is formed on the entire peripheral portion of the above, and slits 3 having hs of 1 μm and 50 μm are formed in the adhesive layer 2 for sealing an electronic component element of the present embodiment Since the thin adhesive layer is formed at the lowest point of the slit 3 in the lid material, when the adhesive layer 2 around the slit 3 is melted by heat to cause shoulder shoulder and close the slit, the melted adhesive The agent can be cured by contact with the molten adhesive located at the lowest point of the slit 3. That is, the slits 3 were densely filled with the adhesive without causing the problem of wettability such as cissing. Therefore, there were no sealing defects. Furthermore, the result of the pressure cracker test for 24 hours was also good, and there was no problem in reliability.

On the other hand, in the sealed state formed in Comparative Example 1, defective sealing occurred. In Comparative Example 1, the thickness of the adhesive layer 2 at the lowest point of the slit 3 is thicker than the adhesive layer 2 constituting the present invention. Therefore, since the size of the slit 3 is too small for the gas to escape from the space formed by the package 6 and the lid material substrate 1, it is considered that a nest or the like is formed in the adhesive layer 2 and a sealing failure occurs. Be done.

The sealed state according to Comparative Example 2 is the slit 3
Since the thin film of the adhesive layer 2 is not formed at the lowest point and the surface of the lid material substrate 2 is exposed, the melted adhesive comes into contact with the above-mentioned surface which does not have satisfactory wettability. , The slit 3 cannot be filled with the adhesive sufficiently densely. Therefore, it is considered that the reliability is lower than that of the lid material of the present invention.

[0040]

According to the lid member for encapsulating an electronic component according to the present invention, an adhesive layer having a thickness of 5 μm or more is formed on the entire peripheral portion of the lid substrate, and at least one or more of the adhesive layers are formed. To
A slit having a thickness of 0.1 μm or more at the lowest point and 3/4 or less of the thickness of the adhesive layer is formed. Thus, a thin adhesive layer is also formed at the lowest point of the slit. For this reason, when the adhesive layer around the slit is melted by heat and shoulder dips are filled to fill the slit of the recess, the melted adhesive comes into contact with the adhesive located at the lowest point of the slit. The slits can be filled with an adhesive without the problem of wettability such as cissing. Therefore, by using the lid member for sealing electronic component elements of the present invention, the lid material substrate and the package can be hermetically sealed with high reliability and stable sealing yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a lid member for sealing an electronic component element of the present invention.

FIG. 2 is a schematic view for explaining a preferable shape of a lid material substrate that constitutes the present invention.

FIG. 3 is a cross-sectional view showing a ceramic package hermetically sealed using a glass substrate in an example.

FIG. 4 is a perspective view showing a ceramic package and a glass substrate shown in FIG.

FIG. 5 is a schematic view showing a state in which a conventional lid member for sealing electronic component elements is viewed from above a lid material substrate.

FIG. 6 is a cross-sectional view showing a conventional lid member for sealing electronic component elements.

[Explanation of symbols]

 1 Cover Material Substrate 2 Adhesive Layer 3 Slit 4 Slit Bottom 5 Electronic Component Element 6 Package A Height of Chamfer X B Width of Chamfer X T Thickness of Cover Material X Chamfer Y Chamfer

Continuation of front page (56) Reference JP-A-5-47948 (JP, A) JP-A-61-256656 (JP, A) JP-A-5-326730 (JP, A)

Claims (3)

(57) [Claims] 1. An adhesive layer having a thickness of 5 μm or more is formed on the entire peripheral portion of the lid material substrate, the thickness of the lowest point is 0.1 μm or more, and 3/4 of the thickness of the adhesive layer. less slit is formed above at least one position of the adhesive layer is, the electronic component element encapsulation cover member characterized that you the adhesive layer is made of a thermosetting resin. 2. The Vickers hardness of the thermosetting resin is
It is in the range of 0.2 to 10.0.
The lid member for sealing an electronic component element according to 1. 3. The electronic component according to claim 1, wherein the cover material substrate is made of glass, quartz, or transparent thermosetting or thermoplastic resin, and the electronic component element is a solid-state image sensor. Lid for element sealing.