JP2006096575A - Method of manufacturing cover glass for semiconductor package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a cover glass for a semiconductor package by which the surface is easily polished and the increase of α-ray emission caused by the sticking of abrasive containing U or Th on the surface is prevented. <P>SOLUTION: A glass chip having ≤0.01 c/cm<SP>2</SP>×hr α-ray emission is manufactured by polishing the surface of large-sized glass, removing the peripheral part thereof and chipping the inside part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a cover glass for a semiconductor package, and more specifically, is attached to the front surface of a semiconductor package that houses a solid-state image sensor, and is suitable for protecting the solid-state image sensor and using it as a light-transmitting window. The present invention relates to a method for manufacturing a semiconductor glass cover glass.

  A cover glass having a flat light-transmitting surface is disposed on the front surface of the solid-state imaging device to protect the semiconductor device. This cover glass was sealed in a package formed of a ceramic material such as alumina, a metal material, or a resin material using adhesives made of various organic resins or low-melting glass, and stored inside the package. It protects the solid-state image sensor and functions as a transparent window for visible light and the like.

  Optical semiconductors that are widely used at present as solid-state imaging devices include a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS). CCDs are mainly mounted on video cameras in order to capture high-definition images, but in recent years, the use range of images has been rapidly expanded as the use of image data processing has accelerated. In particular, they are mounted on digital still cameras and mobile phones, and are increasingly used to convert high-definition images into electronic information data. CMOS, also called complementary metal oxide semiconductor, can be downsized compared to a CCD, consumes less than 1/5 power, and can utilize the manufacturing process of a microprocessor. However, it is advantageous in that it is inexpensive and can be manufactured at low cost, and it is increasingly installed in image input devices such as mobile phones and small personal computers.

  By the way, since a solid-state imaging device generates a soft error due to α rays emitted from the cover glass, the cover glass is required to have a small amount of radioactive isotopes that emit α rays. Among radioisotopes, the amount of alpha rays emitted from uranium (U) and thorium (Th) is particularly large, which is likely to be a problem.

U and Th in the glass are mainly mixed from the glass raw material and the manufacturing process. For this reason, attempts have been made to use high-purity raw materials with little U and Th as glass raw materials, or to mix U and Th in glass melting and processing steps, and not to adhere to the glass surface. (For example, Patent Documents 1 and 2)
JP-A-5-275074 Japanese Patent No. 3532178

By the way, since the surface (both light-transmitting surfaces) of the cover glass for a semiconductor package is required to be flat and transparent, the surface is subjected to polishing. In this polishing process, an abrasive (CeO ₂ ) is used, but CeO ₂ contains U and Th as impurities, and if this adheres to the cover glass, the amount of α-rays emitted from the cover glass is large. Become. Most of the CeO ₂ adhering to the cover glass is removed by washing, but since the end other than the surface (translucent surface) is a cut surface or a rough surface, the CeO ₂ adhering thereto is washed. However, it is very difficult to remove them completely.

In recent years, there is an increasing demand for flatness in cover glass for solid-state imaging devices, and for example, it is desired that the surface roughness (Ra) be 1.0 nm or less. Therefore, it is necessary to lengthen the polishing time of the cover glass, and the amount of CeO ₂ adhering to the end portion of the cover glass tends to increase.

Under such circumstances, in Patent Document 2, the uneven portion at the end of the cover glass is smoothed in advance by acid treatment, etching, or the like, thereby preventing CeO _{2 from} being fixed during polishing, or covering the cover glass. After polishing the glass, it has been proposed to remove the surface layer at the end by acid treatment, etching or the like.

  However, since the cover glass for solid-state image sensors currently commercially available or prototyped is a glass piece having a length of 1 to 30 mm, a width of 1 to 30 mm, and a thickness of about 0.3 to 1.5 mm, workability during polishing is poor. Moreover, in order to polish such a cover glass, a special polishing apparatus capable of fixing the cover glass is required, which raises a problem of an increase in production cost. In particular, when the cover glass becomes ultra-small and thin with a length of 10 mm or less, a width of 10 mm or less, and a thickness of 1.0 mm or less, the polishing efficiency is extremely lowered, which is a serious problem.

Further, after polishing the surface of the cover glass, when the edge thereof is removed by etching, CeO ₂ fixed to the cover glass is mixed into the etching solution, and it adheres to a part of the cover glass again, and emits α rays. There is also a risk of increasing the amount.

  The present invention has been made in view of the above circumstances, and can easily polish the surface, and the amount of α-ray emission from the cover glass caused by the adhesion of an abrasive containing U and Th to the surface. It aims at providing the manufacturing method of the cover glass for semiconductor packages which can prevent an increase.

The method for manufacturing a cover glass for a semiconductor package of the present invention, which has been made to solve the above technical problem, comprises polishing the surface of a large plate glass, then removing the peripheral portion thereof, and chopping the inner portion. In this way, a glass piece having an α-ray emission amount of 0.01 c / cm ² · hr or less is produced.

  According to the method for manufacturing a cover glass for a semiconductor package of the present invention, since the surface of the large plate glass (both light-transmitting surfaces) is polished, the cover glass (glass piece) is produced as before, and then the surface is polished. Compared with this, the handling property is excellent and a special polishing apparatus is not required, so that the polishing cost can be reduced.

  Moreover, normally, when the surface of a large plate glass is polished, the abrasive fixed to the peripheral edge portion cannot be removed by washing, but in the present invention, this portion is a cover glass because the peripheral portion is removed in a later step. It is never used as a (product). In other words, in the present invention, since the inner portion excluding the peripheral portion of the large plate glass is shredded to produce a product (cover glass), no abrasive remains on the surface or end of the cover glass, It is possible to completely prevent an increase in the amount of α-ray emission due to U and Th.

In the method for producing a cover glass for a semiconductor package according to the present invention, after polishing the surface of a large plate glass, the inner portion excluding the peripheral portion is shredded, and the amount of α-ray emission is 0.01 c / cm ² · hr or less The glass piece is made.

  In the present invention, the surface of the large plate glass is first polished. The larger the area of the large glass to be used, the more cover glass can be collected, which is preferable because productivity is improved. However, when the area becomes extremely large, precise polishing becomes difficult. Therefore, the size of the large plate glass is suitably 50 to 1000 mm (preferably 100 to 700 mm) and 50 to 1500 mm (preferably 100 to 700 mm). Further, the thickness of the large glass before polishing is suitably set to 0.5 to 2 mm in consideration of the strength and workability of the glass.

  In the present invention, the removal of the peripheral portion of the large glass and the shredding of the inner portion may be performed by a cutting method. As the cutting method, a method of cutting the peripheral edge portion of the large plate glass with a cutting machine or forming a scribe line with a diamond tip or a laser beam and then folding it is taken. What is necessary is just to cut | disconnect large plate glass in a grid shape. That is, the large glass sheet may be cut in the vertical direction at a predetermined interval (for example, 1 to 30 mm pitch), and further cut in the horizontal direction at a predetermined interval (for example, 1 to 30 mm pitch). Further, it is desirable to remove the peripheral edge portion of the large glass plate with the smallest possible width. That is, as the width of the peripheral edge portion decreases, the area of the inner portion that becomes the product increases. Therefore, the width of the peripheral edge is 1 to 15 mm, preferably 3 to 10 mm.

  Further, the removal of the peripheral edge of the large glass may be performed before the inner portion is shredded, or may be performed at the same time when the inner portion is shredded. That is, after removing (cutting) the peripheral edge of the large plate glass in advance, a portion other than the peripheral portion (inner portion) may be shredded to a predetermined size, or when shredding the large glass, Only the inner part may be used as a product and the peripheral part may be removed. In addition, it is desirable to reuse a peripheral part as a glass raw material (glass cullet) from a viewpoint of resource saving.

In addition, since the cover glass for a semiconductor package of the present invention has an α-ray emission amount of 0.01 c / cm ² · hr or less, a soft error of the solid-state imaging device due to the α-ray can be suppressed. Since solid-state image sensors are becoming more susceptible to soft errors due to alpha rays as the number of pixels increases and the size is reduced, the alpha emission amount of the cover glass is 0.005 c / cm ² · hr. In the following, it is more preferable to set it to 0.003 c / cm ² · hr or less. In order to achieve such low α-rays, a high-purity raw material with little radioisotope (U, Th, etc.) is used in the production of the cover glass, or a melting tank for melting the raw material is used in a radioactive isotope. It is desirable to take measures such as forming from refractories with few elements and platinum. Further, in order to reduce the α-ray emission amount of the cover glass in this way, the U amount in the glass is 5 ppb or less, the Th amount is 10 ppb or less, the U amount is 2 ppb or less, and the Th amount is 8 ppb or less. Is desirable. The amount of α emitted from Th is said to be about 1/10 of the amount of α emitted from U, and the allowable amount of Th in the glass is larger than the allowable amount of U.

Moreover, in this invention, it is preferable to chamfer the edge part of the glass piece obtained by shredding large plate glass. The reason is that the cut surface after shredding the glass is very rough, and glass chips are generated from it, which easily contaminates the surface of the cover glass (translucent surface), and cracks and chips are likely to occur. It is. The chamfering of the cover glass is preferably performed by an etching method because a very smooth end surface (R surface) is obtained. As an etching treatment method, at least the end portion of the glass piece is subjected to a solution eroding with hydrofluoric acid or an equivalent glass such as HF-H ₂ O, HF-H ₂ SO ₄ (or HCl, HNO). ₃ , CH ₃ COOH) —H ₂ O system, NH ₄ F—H ₂ O system and the like.

  Further, according to the method of the present invention, even if the surface of the large plate glass is polished for a long time, the abrasive does not remain on the cover glass as a product. Therefore, for example, even if polishing is performed for a long time so that the surface roughness (Ra) of the light-transmitting surface of the cover glass is 1.0 nm or less, a problem of α-ray emission due to U and Th in the polishing agent occurs. There is nothing. In the cover glass, as the surface roughness (Ra) of the light-transmitting surface decreases, the incidence of malfunction of the element due to scattered light on the light-transmitting surface decreases, and the accuracy of image inspection for detecting foreign matter and the like improves. For this reason, the thickness is preferably 0.5 nm or less, more preferably 0.3 nm or less. The surface roughness (Ra) represents the quality of the surface smoothness and is measured by applying a test method based on the arithmetic mean roughness defined in JIS B0601-1994. Can do.

Further, as described above, the cover glass for a semiconductor package used for a CCD or CMOS is used as a light-transmitting window, so that it is required that bubbles, striae, crystals, platinum defects, etc. do not exist inside the glass. Further, this type of glass has excellent weather resistance so that the surface quality does not deteriorate over a long period of time, and the alkali elution amount is 1.0 mg or less (preferably 0.1 mg or less, more preferably 0.05 mg or less). Is required. That is, devices such as video cameras, digital still cameras, mobile phones, and PDAs (Personal Digital Assistants) may be used outdoors, so they have stable weather resistance and are used outdoors in harsh environments. However, the surface quality must not be deteriorated. Therefore, it is desired that the weather resistance be improved by reducing the alkali elution amount particularly in the cover glass used for this purpose. Further, this type of glass has an average coefficient of thermal expansion of 30 to 85 × 10 ⁻⁷ / ° C. in a temperature range of 30 to 380 ° C., and an alumina package (about approx. 70 × 10 ⁻⁷ / ° C.) and various resin packages, it is also required that a good sealing state can be maintained over a long period of time without distortion occurring. A preferable thermal expansion coefficient of the cover glass is 35 to 80 × 10 ⁻⁷ / ° C., and a more preferable thermal expansion coefficient is 50 to 75 × 10 ⁻⁷ / ° C.

To satisfy such required properties, in _{mass%, SiO 2 58~75%, Al} 2 O 3 0.5~15%, B 2 O 3 5~25%, alkali metal oxides 1-20%, It is desirable to employ a cover glass containing a basic composition of alkaline earth metal oxides 0-20% and ZnO 0-10%.

  The reasons for limitation of each component constituting the above glass are shown below.

SiO ₂ is a main component serving as a skeleton constituting the glass, and is effective in improving the weather resistance of the glass. However, when the amount is too large, the high temperature viscosity of the glass is increased and the meltability is deteriorated. Therefore, the content of SiO ₂ is 58 to 75%, preferably 58 to 72%, more preferably 60 to 70%, and most preferably 60 to 68.5%.

Al ₂ O _{3 is} also a component that improves the weather resistance of the glass, but if it is too much, the high-temperature viscosity of the glass tends to increase and the meltability tends to deteriorate. Therefore, the content of Al ₂ O ₃ is 0.5 to 15%, preferably 1.1 to 12%, more preferably 3.5 to 12%, and most preferably 6 to 11%.

B ₂ O ₃ is a component that acts as a flux, lowers the viscosity of the glass, and improves the meltability. However, if the amount of B ₂ O ₃ increases too much, the weather resistance of the glass tends to decrease. Therefore, the content of B ₂ O ₃ is 5 to 25%, preferably 9 to 20%, more preferably 11 to 18%, and most preferably 12 to 18%.

Alkali metal oxides (Na ₂ O, K ₂ O, Li ₂ O) are components that lower the viscosity of the glass, improve the meltability, and effectively adjust the coefficient of thermal expansion. The weather resistance of the glass is significantly deteriorated. Therefore, the content of the alkali metal oxide is 1 to 20%, preferably 5 to 18%, more preferably 7 to 13%.

  Alkaline earth metal oxides (MgO, CaO, SrO, BaO) are components that improve the weather resistance of the glass, lower the viscosity of the glass, and improve the meltability. It tends to be transparent and the density tends to increase. Therefore, the content of the alkaline earth metal oxide is 0 to 20%, preferably 0.5 to 18%, more preferably 1 to 18%.

  In particular, CaO is a component for which a high-purity raw material can be obtained relatively easily and the melting property and weather resistance of glass are remarkably improved, and is preferably contained in an amount of 0.5 to 10%, more preferably 1 to 8%. Moreover, since BaO and SrO tend to increase the density, when considering the weight reduction of the glass, the total content is restricted to 13% or less, preferably 10% or less, more preferably 7% or less. Should. Moreover, since BaO and SrO are easy to contain a radioisotope in a raw material, it is preferable to regulate each to 3% or less, and further 1.4% or less.

ZnO is excellent in the effect of improving the weather resistance, improves the meltability of the glass, and is effective in suppressing the volatilization of B ₂ O ₃ and alkali metal oxides from the molten glass. In particular, when the content of Al ₂ O ₃ is 3% or less, the weather resistance tends to be remarkably lowered, so that ZnO is preferably contained in an amount of 2% or more, more preferably 4.5% or more. However, if ZnO is contained in a large amount, the glass tends to be devitrified and the density increases, so it should be suppressed to 10% or less, preferably 9% or less, more preferably 6% or less.

Furthermore, in the present invention, in addition to the above components, components such as P ₂ O ₅ , Y ₂ O ₃ , Nb ₂ O ₃ , La ₂ O _{3 and the} like are contained in an amount not exceeding 5%, Various fining agents can be contained up to 3%. As the fining agent, one or more of Sb ₂ O ₃ , Sb ₂ O ₅ , F ₂ , Cl ₂ , C, SO ₃ , SnO ₂ , or metal powders such as Al and Si can be used.

As ₂ O ₃ generates a clarified gas in a wide temperature range (about 1300 to 1700 ° C.), and has been widely used as a clarifier for this type of glass. Easy to include. Therefore, As ₂ O ₃ should be substantially not contained. PbO and CdO are environmentally hazardous substances and should be avoided. Furthermore, Sb ₂ O ₃ and Sb ₂ O ₅ are components with excellent clarification effects as well as As ₂ O ₃ , but they are also environmentally hazardous substances. Is desirable.

The actual amount of fining agent used is 0.05 to 2.0% of the total amount of Sb ₂ O ₃ and Sb ₂ O ₅ , and the total amount of F ₂ , Cl ₂ , SO ₃ , C, and SnO _2. from 0.1 to 3.0% (particularly _{Cl 2 0.005~1.0%, SnO 2 0.01~1.0} %) proportion of is preferred.

  There are roughly two methods for producing the large glass used in the present invention.

  The first method is to melt the glass raw material in a melting tank, homogenize it by defoaming and removing striae, and then cast the glass melt into a mold or cast the glass melt on a stretched plate. Are continuously drawn out and formed into a predetermined shape. Next, the obtained glass molded body is gradually cooled, cut into a constant thickness, and then subjected to polishing on the surface to form a large plate glass having a predetermined thickness.

  The second method is to melt glass raw material in a melting tank, homogenize it by defoaming and striae removal, and then mold the glass melt into a large glass plate with a predetermined shape by the downdraw method or float method. The method of polishing the surface. Since the surface of the large glass formed by the downdraw method or the float method is excellent in surface smoothness, there is an advantage that the polishing time can be shortened and the productivity can be improved.

  Further, in the present invention, the surface of the large glass is polished and then shredded into a predetermined size. For example, even an ultra-small thin cover glass having a length of 10 mm or less, a width of 10 mm or less, and a thickness of 1.0 mm or less can be easily obtained Can be produced. In particular, the thickness of the cover glass is not preferable because it easily affects the characteristics, and as the thickness increases, the transmittance decreases, and it becomes difficult to reduce the weight and thickness of the device. Also, if the thickness is too thin, the practical strength is insufficient, or the deflection of the large glass becomes large and handling becomes difficult, so that it is 0.05 to 1.0 mm, and further 0.1 to 0.5 mm. Is preferred.

  Next, an example of the manufacturing method of the cover glass for semiconductor packages of this invention is demonstrated.

  First, a glass raw material formulation is prepared so as to obtain a glass having a desired composition. As the glass raw material, a high-purity raw material with few impurities such as U and Th is used. More specifically, a high-purity raw material having U and Th contents of 5 ppb or less is used. Next, the glass raw material is charged into a melting tank and melted. As the melting tank, a container made of platinum (including a platinum rhodium container) or a refractory (for example, an alumina refractory or a quartz refractory) having a low U and Th content is preferable. Next, homogenization (defoaming and striae removal) of the molten glass is performed in a clarification tank. This clarification tank may also be made from platinum or refractory with a low U and Th content.

Thereafter, the homogenized molten glass is poured into a mold and cast to form a glass lump (glass ingot). Next, this glass ingot is cut into a predetermined thickness (slicing cutting) with a cutting machine to produce a plurality of large glass plates. The thickness of the large glass plate may be slightly larger than the thickness of the final product. Next, both sides of the large plate glass are polished to make a smooth surface. Since this polishing step is performed while supplying a slurry in which an abrasive (CeO ₂ ) is dispersed in water or the like, the abrasive will adhere to the surface of the large glass plate. Most of the abrasive can be removed by washing the large glass, but the peripheral edge of the large glass is an uneven surface, so that the abrasive tends to adhere after washing.

  Then, a small glass piece is produced by chopping large plate glass into a predetermined dimension with a cutting machine. At this time, the peripheral end portion of the large glass plate is removed, and only the inner portion other than the peripheral portion is shredded to produce a large number of glass pieces. Next, after chamfering the peripheral edge of each glass piece by etching, it is washed and dried to produce a cover glass.

  Hereinafter, the present invention will be described based on examples.

  FIG. 1 is a perspective view showing a large glass 10 to be shredded in the present invention, and has a size of 200 mm in length, 300 mm in width, and 0.5 mm in thickness. This large glass 10 is comprised from the inner part 10a used as a product (cover glass), and the peripheral part 10b which is not used as a product.

  Next, a method for producing the large glass 10 of FIG. 1 and a method for producing a cover glass from the large glass 10 will be described.

First, by mass, SiO ₂ 68%, Al ₂ O ₃ 5%, B ₂ O ₃ 10%, Na ₂ O 12%, CaO 4%, ZnO 0.9%, Sb ₂ O ₃ 0.1% After the high-purity glass raw material prepared so as to be melted in a platinum container at 1550 ° C. for 6 hours, the glass homogenized in the platinum container is poured into a mold to make 800 × 300 × 200 mm Cast-molded. The glass ingot thus obtained was sliced and cut by using a wire saw or the like, and a plurality of large glass plates having dimensions of 200 mm in length, 300 mm in width, and 1.5 mm in thickness were produced. Next, by polishing both sides of these large glass plates using a rotary polishing processing machine, as shown in FIG. 1, they have dimensions of 200 mm in length, 300 mm in width, and 0.5 mm in thickness. A plurality of large glass plates 10 having a roughness (Ra) of 0.3 nm or less were produced.

  Next, as shown in FIG. 2, a temporary bonding adhesive 11 was filled in a gap between a plurality of large glass plates 10 and fixed to prepare a laminated body 12, which was then placed on a base 13. In addition, when laminating the large glass 10, a spacing material such as a bead may be interposed so that the interval is constant (for example, about 0.2 to 0.5 mm). Further, as the temporary fixing adhesive 11, an acid-resistant resin (for example, pine resin, coal tar pitch, or the like) that is not eroded by an etching solution used in a subsequent process is used.

  Next, as shown in FIG. 3, the peripheral edge portion 10 b of the large glass sheet 10 is removed using a multi-blade cutting machine 14 provided with a plurality of rotating cutting blades (width 2 mm) 14 b on a rotary drive shaft 14 a at a pitch of 10 mm. The inner portion 10a was cut into a grid pattern in the vertical and horizontal directions. In this shredding process, first, the width of both ends (peripheries) in the longitudinal direction (200 mm) of the large plate glass 10 was set to 4 mm, and the inner portion 10a was divided into 16 pieces. Next, it set so that the width | variety of the both ends (peripheral part) of the horizontal direction (300 mm) of the large plate glass 10 might be set to 6 mm, respectively, and the inner part 10a was divided | segmented into 24 sheets. In this way, 384 pieces of glass piece laminates having dimensions of 10 × 10 × 0.5 mm were produced.

  Next, after chamfering the laminated body of glass pieces, the ends of each glass piece are chamfered (surface treatment and thread chamfering) by immersing in an etching solution such as hydrofluoric acid, and then washed with water. The etching solution was removed by Thereafter, the laminate is immersed in a solvent (for example, acetone, chloroform, perchlorethylene, etc.), the temporary adhesive 11 is dissolved in the solvent to separate the glass pieces, and then the glass pieces are washed and dried to cover them. Glass was produced.

The cover glass thus obtained had dimensions of 10 mm in length, 10 mm in width, and 0.5 mm in thickness, and its peripheral end portion was a smooth curved surface (R surface), and no adhesion of abrasive was observed. Further, when the amounts of U and Th in the glass and the amount of α-ray emission were measured, the amount of U was 2 ppb or less, the amount of Th was 2 ppb or less, and the amount of α-ray emission was 0.002 c / cm ² · hr or less. The thermal expansion coefficient was 66 × 10 ⁻⁷ / ° C., and the alkali elution amount was 0.06 mg. Further, since the temperature corresponding to the viscosity of 10 ^2.5 dPa · s was 1350 ° C. or less, the meltability was excellent.

In addition, said surface roughness (Ra) was measured using the stylus type surface roughness measuring machine Taly step (made by Taylor-Hobson). The contents of U and Th were measured by ICP-MASS, and the amount of α-ray emission was measured using an ultra-low level α-ray measuring apparatus (LACS-4000M manufactured by Sumitomo Chemical Co., Ltd.). The coefficient of thermal expansion was determined by measuring an average coefficient of thermal expansion in a temperature range of 30 to 380 ° C. using a dilatometer. The alkali elution amount was measured based on JIS R3502. The 10 ^2.5 Pa · s temperature is obtained by measuring a temperature corresponding to a high temperature viscosity of 10 ^2.5 poise, and the lower this value, the better the meltability.

According to the production method of the present invention, large glass is polished, so that the productivity is excellent, and adhesion of abrasives (CeO ₂ ) containing U and Th can be completely prevented. A cover glass for a semiconductor package can be manufactured at low cost.

It is a perspective view which shows the large plate glass used by this invention. In the manufacturing method of this invention, it is a perspective view which shows the state which mounted the laminated body of the large plate glass on the base. In the manufacturing method of this invention, it is a perspective view which shows the process of shredding the laminated body of large plate glass.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Large plate glass 10a Inner part 10b Peripheral part 11 Temporary fixing adhesive 12 Large plate glass laminated body 13 Base 14 Multiblade cutting machine

Claims (13)

After polishing the surface of the large plate glass, the peripheral edge portion is removed, and the inner portion is shredded to produce a glass piece having an α-ray emission amount of 0.01 c / cm ² · hr or less. A method for producing a semiconductor package cover glass.   The method for producing a cover glass for a semiconductor package according to claim 1, wherein the peripheral edge of the large glass plate is removed before the shredding process.   2. The method for producing a cover glass for a semiconductor package according to claim 1, wherein a peripheral portion of the large plate glass is removed at the time of shredding.   The method for producing a cover glass for a semiconductor package according to any one of claims 1 to 3, wherein the glass piece has a surface roughness (Ra) of 1.0 nm or less.   The method for producing a cover glass for a semiconductor package according to any one of claims 1 to 4, wherein the glass piece has a length of 10 mm or less, a width of 10 mm or less, and a thickness of 1.0 mm or less.   The method for producing a cover glass for a semiconductor package according to any one of claims 1 to 5, wherein the U content in the glass is 5 ppb or less and the Th amount is 10 ppb or less.   The cover glass for a semiconductor package according to any one of claims 1 to 6, wherein the cover glass is shredded using a cutting machine.   8. The method of manufacturing a cover glass for a semiconductor package according to claim 7, wherein a plurality of large glass sheets are laminated and then chopped using a cutting machine.   The method for producing a cover glass for a semiconductor package according to any one of claims 1 to 6, wherein the scribe line is formed and then chopped by folding. By _{mass%, SiO 2 58~75%, Al} 2 O 3 0.5~15%, B 2 O 3 5~25%, alkali metal oxides 1-20% alkaline earth metal oxide 0-20% ZnO 0-10% of basic composition is contained, The manufacturing method of the cover glass for semiconductor packages in any one of Claims 1-9 characterized by the above-mentioned.   The method for producing a cover glass for a semiconductor package according to any one of claims 1 to 10, wherein the edge of the glass piece is chamfered.   12. The method of manufacturing a cover glass for a semiconductor package according to claim 11, wherein the chamfering is performed by an etching process.   It is used for the package which accommodates a solid-state image sensor, The manufacturing method of the cover glass for semiconductor packages in any one of Claims 1-12 characterized by the above-mentioned.